Skip to content

Installing a cluster with RHEL KVM on IBM Z and IBM LinuxONE in a disconnected environment

In OpenShift Container Platform version 4.19, you can install a cluster on IBM Z® or IBM® LinuxONE infrastructure that you provision in a disconnected environment.

Note

While this document refers to only IBM Z®, all information in it also applies to IBM® LinuxONE.

Prerequisites

About installations in restricted networks

In OpenShift Container Platform 4.19, you can perform an installation that does not require an active connection to the internet to obtain software components. Restricted network installations can be completed using installer-provisioned infrastructure or user-provisioned infrastructure, depending on the cloud platform to which you are installing the cluster.

If you choose to perform a restricted network installation on a cloud platform, you still require access to its cloud APIs. Some cloud functions, like Amazon Web Service’s Route 53 DNS and IAM services, require internet access. Depending on your network, you might require less internet access for an installation on bare metal hardware, Nutanix, or on VMware vSphere.

To complete a restricted network installation, you must create a registry that mirrors the contents of the OpenShift image registry and contains the installation media. You can create this registry on a mirror host, which can access both the internet and your closed network, or by using other methods that meet your restrictions.

Important

Because of the complexity of the configuration for user-provisioned installations, consider completing a standard user-provisioned infrastructure installation before you attempt a restricted network installation using user-provisioned infrastructure. Completing this test installation might make it easier to isolate and troubleshoot any issues that might arise during your installation in a restricted network.

Additional limits

Clusters in restricted networks have the following additional limitations and restrictions:

  • The ClusterVersion status includes an Unable to retrieve available updates error.

  • By default, you cannot use the contents of the Developer Catalog because you cannot access the required image stream tags.

Preparing the user-provisioned infrastructure

To ensure a successful deployment and meet cluster requirements in OpenShift Container Platform, prepare your user-provisioned infrastructure before starting the installation. Configuring your compute, network, and storage components in advance provides the stable foundation necessary for the installation program to function correctly.

This section provides details about the high-level steps required to set up your cluster infrastructure in preparation for an OpenShift Container Platform installation. This includes configuring IP networking and network connectivity for your cluster nodes, enabling the required ports through your firewall, and setting up the required DNS and load balancing infrastructure.

After preparation, your cluster infrastructure must meet the requirements outlined in the Requirements for a cluster with user-provisioned infrastructure section.

Prerequisites
Procedure

  1. If you are using DHCP to provide the IP networking configuration to your cluster nodes, configure your DHCP service.

    1. Add persistent IP addresses for the nodes to your DHCP server configuration. In your configuration, match the MAC address of the relevant network interface to the intended IP address for each node.

    2. When you use DHCP to configure IP addressing for the cluster machines, the machines also obtain the DNS server information through DHCP. Define the persistent DNS server address that is used by the cluster nodes through your DHCP server configuration.

      Note

      If you are not using a DHCP service, you must provide the IP networking configuration and the address of the DNS server to the nodes at RHCOS install time. These can be passed as boot arguments if you are installing from an ISO image. See the Installing RHCOS and starting the OpenShift Container Platform bootstrap process section for more information about static IP provisioning and advanced networking options.

    3. Define the hostnames of your cluster nodes in your DHCP server configuration. See the Setting the cluster node hostnames through DHCP section for details about hostname considerations.

      Note

      If you are not using a DHCP service, the cluster nodes obtain their hostname through a reverse DNS lookup.

  2. Choose to perform either a fast track installation of Red Hat Enterprise Linux CoreOS (RHCOS) or a full installation of Red Hat Enterprise Linux CoreOS (RHCOS). For the full installation, you must set up an HTTP or HTTPS server to provide Ignition files and install images to the cluster nodes. For the fast track installation an HTTP or HTTPS server is not required, however, a DHCP server is required. See sections “Fast-track installation: Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines" and “Full installation: Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines".

  3. Ensure that your network infrastructure provides the required network connectivity between the cluster components. See the Networking requirements for user-provisioned infrastructure section for details about the requirements.

  4. Configure your firewall to enable the ports required for the OpenShift Container Platform cluster components to communicate. See Networking requirements for user-provisioned infrastructure section for details about the ports that are required.

    Important

    By default, port 1936 is accessible for an OpenShift Container Platform cluster, because each control plane node needs access to this port.

    Avoid using the Ingress load balancer to expose this port, because doing so might result in the exposure of sensitive information, such as statistics and metrics, related to Ingress Controllers.

  5. Setup the required DNS infrastructure for your cluster.

    1. Configure DNS name resolution for the Kubernetes API, the application wildcard, the bootstrap machine, the control plane machines, and the compute machines.

    2. Configure reverse DNS resolution for the Kubernetes API, the bootstrap machine, the control plane machines, and the compute machines.

      See the User-provisioned DNS requirements section for more information about the OpenShift Container Platform DNS requirements.

  6. Validate your DNS configuration.

    1. From your installation node, run DNS lookups against the record names of the Kubernetes API, the wildcard routes, and the cluster nodes. Validate that the IP addresses in the responses correspond to the correct components.

    2. From your installation node, run reverse DNS lookups against the IP addresses of the load balancer and the cluster nodes. Validate that the record names in the responses correspond to the correct components.

      See the Validating DNS resolution for user-provisioned infrastructure section for detailed DNS validation steps.

  7. Provision the required API and application ingress load balancing infrastructure. See the Load balancing requirements for user-provisioned infrastructure section for more information about the requirements.

    Note

    Some load balancing solutions require the DNS name resolution for the cluster nodes to be in place before the load balancing is initialized.

Example load balancer configuration for user-provisioned clusters

Reference the example API and application Ingress load balancer configuration so that you can understand how to meet the load balancing requirements for user-provisioned clusters.

The sample is an /etc/haproxy/haproxy.cfg configuration for an HAProxy load balancer. The example is not meant to provide advice for choosing one load balancing solution over another.

Tip

If you are using HAProxy as a load balancer, you can check that the haproxy process is listening on ports 6443, 22623, 443, and 80 by running netstat -nltupe on the HAProxy node.

In the example, the same load balancer is used for the Kubernetes API and application ingress traffic. In production scenarios, you can deploy the API and application ingress load balancers separately so that you can scale the load balancer infrastructure for each in isolation.

Note

If you are using HAProxy as a load balancer and SELinux is set to enforcing, you must ensure that the HAProxy service can bind to the configured TCP port by running setsebool -P haproxy_connect_any=1.

Sample API and application Ingress load balancer configuration
global
  log         127.0.0.1 local2
  pidfile     /var/run/haproxy.pid
  maxconn     4000
  daemon
defaults
  mode                    http
  log                     global
  option                  dontlognull
  option http-server-close
  option                  redispatch
  retries                 3
  timeout http-request    10s
  timeout queue           1m
  timeout connect         10s
  timeout client          1m
  timeout server          1m
  timeout http-keep-alive 10s
  timeout check           10s
  maxconn                 3000
listen api-server-6443
  bind *:6443
  mode tcp
  option  httpchk GET /readyz HTTP/1.0
  option  log-health-checks
  balance roundrobin
  server bootstrap bootstrap.ocp4.example.com:6443 verify none check check-ssl inter 10s fall 2 rise 3 backup
  server master0 master0.ocp4.example.com:6443 weight 1 verify none check check-ssl inter 10s fall 2 rise 3
  server master1 master1.ocp4.example.com:6443 weight 1 verify none check check-ssl inter 10s fall 2 rise 3
  server master2 master2.ocp4.example.com:6443 weight 1 verify none check check-ssl inter 10s fall 2 rise 3
listen machine-config-server-22623
  bind *:22623
  mode tcp
  server bootstrap bootstrap.ocp4.example.com:22623 check inter 1s backup
  server master0 master0.ocp4.example.com:22623 check inter 1s
  server master1 master1.ocp4.example.com:22623 check inter 1s
  server master2 master2.ocp4.example.com:22623 check inter 1s
listen ingress-router-443
  bind *:443
  mode tcp
  balance source
  server compute0 compute0.ocp4.example.com:443 check inter 1s
  server compute1 compute1.ocp4.example.com:443 check inter 1s
listen ingress-router-80
  bind *:80
  mode tcp
  balance source
  server compute0 compute0.ocp4.example.com:80 check inter 1s
  server compute1 compute1.ocp4.example.com:80 check inter 1s

where:

listen api-server-6443

Port 6443 handles the Kubernetes API traffic and points to the control plane machines.

server bootstrap bootstrap.ocp4.example.com

The bootstrap entries must be in place before the OpenShift Container Platform cluster installation and they must be removed after the bootstrap process is complete.

listen machine-config-server

Port 22623 handles the machine config server traffic and points to the control plane machines.

listen ingress-router-443

Port 443 handles the HTTPS traffic and points to the machines that run the Ingress Controller pods. The Ingress Controller pods run on the compute machines by default.

listen ingress-router-80

Port 80 handles the HTTP traffic and points to the machines that run the Ingress Controller pods. The Ingress Controller pods run on the compute machines by default.

Note

If you are deploying a three-node cluster with zero compute nodes, the Ingress Controller pods run on the control plane nodes. In three-node cluster deployments, you must configure your application Ingress load balancer to route HTTP and HTTPS traffic to the control plane nodes.

Manually creating the installation configuration file

To customise your OpenShift Container Platform deployment and meet specific network requirements, manually create the installation configuration file. This ensures that the installation program uses your tailored settings rather than default values during the setup process.

Prerequisites

  • You have an SSH public key on your local machine for use with the installation program. You can use the key for SSH authentication onto your cluster nodes for debugging and disaster recovery.

  • You have obtained the OpenShift Container Platform installation program and the pull secret for your cluster.

Procedure

  1. Create an installation directory to store your required installation assets in:

    $ mkdir <installation_directory>

    Important

    You must create a directory. Some installation assets, such as bootstrap X.509 certificates have short expiration intervals, so you must not reuse an installation directory. If you want to reuse individual files from another cluster installation, you can copy them into your directory. However, the file names for the installation assets might change between releases. Use caution when copying installation files from an earlier OpenShift Container Platform version.

  2. Customize the provided sample install-config.yaml file template and save the file in the <installation_directory>.

    Note

    You must name this configuration file install-config.yaml.

  3. Back up the install-config.yaml file so that you can use it to install many clusters.

    Important

    Back up the install-config.yaml file now, because the installation process consumes the file in the next step.

Additional resources

Sample install-config.yaml file for IBM Z

You can customize the install-config.yaml file to specify more details about your OpenShift Container Platform cluster platform or modify the values of the required parameters.

apiVersion: v1
baseDomain: example.com
compute:
- hyperthreading: Enabled
  name: worker
  replicas: 0
  architecture: s390x
controlPlane:
  hyperthreading: Enabled
  name: master
  replicas: 3
  architecture: s390x
metadata:
  name: test
networking:
  clusterNetwork:
  - cidr: 10.128.0.0/14
    hostPrefix: 23
  networkType: OVNKubernetes
  serviceNetwork:
  - 172.30.0.0/16
platform:
  none: {}
fips: false
pullSecret: '{"auths":{"<local_registry>": {"auth": "<credentials>","email": "you@example.com"}}}'
sshKey: 'ssh-ed25519 AAAA...'
additionalTrustBundle: |
  -----BEGIN CERTIFICATE-----
  ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
  -----END CERTIFICATE-----
imageContentSources:
- mirrors:
  - <local_repository>/ocp4/openshift4
  source: quay.io/openshift-release-dev/ocp-release
- mirrors:
  - <local_repository>/ocp4/openshift4
  source: quay.io/openshift-release-dev/ocp-v4.0-art-dev

where:

baseDomain

Specifies the base domain of the cluster. All DNS records must be sub-domains of this base and include the cluster name.

compute

Specifies the compute node configurations, which is a sequence of mappings. To meet the requirements of the different data structures, the first line of the compute section must begin with a hyphen, -.

controlPlane

Specifies the controlPlane node configurations, which is a single mapping. To meet the requirements of the different data structures, the first line of the controlPlane section must not. Only one control plane pool is used.

hyperthreading

Specifies whether to enable or disable simultaneous multithreading (SMT), or hyperthreading. By default, SMT is enabled to increase the performance of the cores in your machines. You can disable it by setting the parameter value to Disabled. If you disable SMT, you must disable it in all cluster machines; this includes both control plane and compute machines.

Note

Simultaneous multithreading (SMT) is enabled by default. If SMT is not available on your OpenShift Container Platform nodes, the hyperthreading parameter has no effect.

Important

If you disable hyperthreading, whether on your OpenShift Container Platform nodes or in the install-config.yaml file, ensure that your capacity planning accounts for the dramatically decreased machine performance.

compute.replicas

Specifies the number of compute machines that the cluster creates and manages for you on installer-provisioned installations. You must set this value to 0 when you install OpenShift Container Platform on user-provisioned infrastructure. Additionally for user-provisioned installations, you must manually deploy the compute machines before you finish installing the cluster.

Note

If you are installing a three-node cluster, do not deploy any compute machines when you install the Red Hat Enterprise Linux CoreOS (RHCOS) machines.

controlPlane.replicas

Specifies the number of control plane machines that you add to the cluster. Because the cluster uses these values as the number of etcd endpoints in the cluster, the value must match the number of control plane machines that you deploy.

metadata.name

Specifies the cluster name that you specified in your DNS records.

clusterNetwork.cidr

Specifies a block of IP addresses from which pod IP addresses are allocated. This block must not overlap with existing physical networks. These IP addresses are used for the pod network. If you need to access the pods from an external network, you must configure load balancers and routers to manage the traffic.

Note

Class E CIDR range is reserved for a future use. To use the Class E CIDR range, you must ensure your networking environment accepts the IP addresses within the Class E CIDR range.

cidr.hostPrefix

Specifies the subnet prefix length to assign to each individual node. For example, if hostPrefix is set to 23, then each node is assigned a /23 subnet out of the given cidr, which allows for 510 (2^(32 - 23) - 2) pod IP addresses. If you are required to provide access to nodes from an external network, configure load balancers and routers to manage the traffic.

networkType

Specifies the cluster network plugin to install. The default value OVNKubernetes is the only supported value.

serviceNetwork

Specifies the IP address pool to use for service IP addresses. You can enter only one IP address pool. This block must not overlap with existing physical networks. If you need to access the services from an external network, configure load balancers and routers to manage the traffic.

platform

Specifies the platform. You must set the platform to none. You cannot provide additional platform configuration variables for IBM Z® infrastructure.

Important

Clusters that are installed with the platform type none are unable to use some features, such as managing compute machines with the Machine API. This limitation applies even if the compute machines that are attached to the cluster are installed on a platform that would normally support the feature. This parameter cannot be changed after installation.

fips

Specifies either enabling or disabling FIPS mode. By default, FIPS mode is not enabled. If FIPS mode is enabled, the Red Hat Enterprise Linux CoreOS (RHCOS) machines that OpenShift Container Platform runs on bypass the default Kubernetes cryptography suite and use the cryptography modules that are provided with RHCOS instead.

Important

To enable FIPS mode for your cluster, you must run the installation program from a Red Hat Enterprise Linux (RHEL) computer configured to operate in FIPS mode. For more information about configuring FIPS mode on RHEL, see Switching RHEL to FIPS mode.

When running Red Hat Enterprise Linux (RHEL) or Red Hat Enterprise Linux CoreOS (RHCOS) booted in FIPS mode, OpenShift Container Platform core components use the RHEL cryptographic libraries that have been submitted to NIST for FIPS 140-2/140-3 Validation on only the x86_64, ppc64le, and s390x architectures.

pullSecret

Specifies the registry domain name for <local_registry>, and optionally the port, that your mirror registry uses to serve content. For example, registry.example.com or registry.example.com:5000. For <credentials>, specify the base64-encoded user name and password for your mirror registry.

sshKey

Specifies the SSH public key for the core user in Red Hat Enterprise Linux CoreOS (RHCOS).

Note

For production OpenShift Container Platform clusters on which you want to perform installation debugging or disaster recovery, specify an SSH key that your ssh-agent process uses.

additionalTrustBundle

Specifies the additionalTrustBundle parameter and value. The value must be the contents of the certificate file that you used for your mirror registry. The certificate file can be an existing, trusted certificate authority or the self-signed certificate that you generated for the mirror registry.

imageContentSources

Specifies the imageContentSources section according to the output of the command that you used to mirror the repository.

Important

  • When using the oc adm release mirror command, use the output from the imageContentSources section.

  • When using oc mirror command, use the repositoryDigestMirrors section of the ImageContentSourcePolicy file that results from running the command.

  • ImageContentSourcePolicy is deprecated. For more information see Configuring image registry repository mirroring.

Configuring the cluster-wide proxy during installation

To enable internet access in environments that deny direct connections, configure a cluster-wide proxy in the install-config.yaml file. This configuration ensures that the new OpenShift Container Platform cluster routes traffic through the specified HTTP or HTTPS proxy.

Prerequisites

  • You have an existing install-config.yaml file.

  • You have reviewed the sites that your cluster requires access to and determined whether any of them need to bypass the proxy. By default, all cluster egress traffic is proxied, including calls to hosting cloud provider APIs. You added sites to the Proxy object’s spec.noProxy field to bypass the proxy if necessary.

    Note

    The Proxy object status.noProxy field is populated with the values of the networking.machineNetwork[].cidr, networking.clusterNetwork[].cidr, and networking.serviceNetwork[] fields from your installation configuration.

    For installations on Amazon Web Services (AWS), Google Cloud, Microsoft Azure, and Red Hat OpenStack Platform (RHOSP), the Proxy object status.noProxy field is also populated with the instance metadata endpoint (169.254.169.254).

Procedure

  1. Edit your install-config.yaml file and add the proxy settings. For example:

    apiVersion: v1
baseDomain: my.domain.com
proxy:
  httpProxy: http://<username>:<pswd>@<ip>:<port>
  httpsProxy: https://<username>:<pswd>@<ip>:<port>
  noProxy: example.com
additionalTrustBundle: |
    -----BEGIN CERTIFICATE-----
    <MY_TRUSTED_CA_CERT>
    -----END CERTIFICATE-----
additionalTrustBundlePolicy: <policy_to_add_additionalTrustBundle>
# ...

    where:

    proxy.httpProxy

    Specifies a proxy URL to use for creating HTTP connections outside the cluster. The URL scheme must be http.

    proxy.httpsProxy

    Specifies a proxy URL to use for creating HTTPS connections outside the cluster.

    proxy.noProxy

    Specifies a comma-separated list of destination domain names, IP addresses, or other network CIDRs to exclude from proxying. Preface a domain with . to match subdomains only. For example, .y.com matches x.y.com, but not y.com. Use * to bypass the proxy for all destinations.

    additionalTrustBundle

    If provided, the installation program generates a config map that is named user-ca-bundle in the openshift-config namespace to hold the additional CA certificates. If you provide additionalTrustBundle and at least one proxy setting, the Proxy object is configured to reference the user-ca-bundle config map in the trustedCA field. The Cluster Network Operator then creates a trusted-ca-bundle config map that merges the contents specified for the trustedCA parameter with the RHCOS trust bundle. The additionalTrustBundle field is required unless the proxy’s identity certificate is signed by an authority from the RHCOS trust bundle.

    additionalTrustBundlePolicy

    Specifies the policy that determines the configuration of the Proxy object to reference the user-ca-bundle config map in the trustedCA field. The allowed values are Proxyonly and Always. Use Proxyonly to reference the user-ca-bundle config map only when http/https proxy is configured. Use Always to always reference the user-ca-bundle config map. The default value is Proxyonly. Optional parameter.

    Note

    The installation program does not support the proxy readinessEndpoints field.

    Note

    If the installer times out, restart and then complete the deployment by using the wait-for command of the installer. For example:

    +

    $ ./openshift-install wait-for install-complete --log-level debug

  2. Save the file and reference it when installing OpenShift Container Platform.

    The installation program creates a cluster-wide proxy that is named cluster that uses the proxy settings in the provided install-config.yaml file. If no proxy settings are provided, a cluster Proxy object is still created, but it will have a nil spec.

    Note

    Only the Proxy object named cluster is supported, and no additional proxies can be created.

Configuring a three-node cluster

To create smaller, resource-efficient clusters for testing and production, deploy a bare-metal cluster with zero compute machines in a minimal three-node cluster. This optional configuration uses only three control plane machines, optimizing infrastructure resources for testing, development, and production purposes.

In three-node OpenShift Container Platform environments, the three control plane machines are schedulable, which means that your application workloads are scheduled to run on them.

Prerequisites

  • You have an existing install-config.yaml file.

Procedure

  • Ensure that the number of compute replicas is set to 0 in your install-config.yaml file, as shown in the following compute stanza:

    compute:
- name: worker
  platform: {}
  replicas: 0
# ...

    Note

    You must set the value of the replicas parameter for the compute machines to 0 when you install OpenShift Container Platform on user-provisioned infrastructure, regardless of the number of compute machines you are deploying. In installer-provisioned installations, the parameter controls the number of compute machines that the cluster creates and manages for you. This does not apply to user-provisioned installations, where the compute machines are deployed manually.

    Note

    The preferred resource for control plane nodes is six vCPUs and 21 GB. For three control plane nodes this is the memory + vCPU equivalent of a minimum five-node cluster. You should back the three nodes, each installed on a 120 GB disk, with three IFLs that are SMT2 enabled. The minimum tested setup is three vCPUs and 10 GB on a 120 GB disk for each control plane node.

For three-node cluster installations, follow these next steps:

  • If you are deploying a three-node cluster with zero compute nodes, the Ingress Controller pods run on the control plane nodes. In three-node cluster deployments, you must configure your application ingress load balancer to route HTTP and HTTPS traffic to the control plane nodes. See the Load balancing requirements for user-provisioned infrastructure section for more information.

  • When you create the Kubernetes manifest files in the following procedure, ensure that the mastersSchedulable parameter in the <installation_directory>/manifests/cluster-scheduler-02-config.yml file is set to true. This enables your application workloads to run on the control plane nodes.

  • Do not deploy any compute nodes when you create the Red Hat Enterprise Linux CoreOS (RHCOS) machines.

Cluster Network Operator configuration

To manage cluster networking, configure the Cluster Network Operator (CNO) Network custom resource (CR) named cluster so the cluster uses the correct IP ranges and network plugin settings for reliable pod and service connectivity. Some settings and fields are inherited at the time of install or by the default.Network.type plugin, OVN-Kubernetes.

The CNO configuration inherits the following fields during cluster installation from the Network API in the Network.config.openshift.io API group:

clusterNetwork

IP address pools from which pod IP addresses are allocated.

serviceNetwork

IP address pool for services.

defaultNetwork.type

Cluster network plugin. OVNKubernetes is the only supported plugin during installation.

You can specify the cluster network plugin configuration for your cluster by setting the fields for the defaultNetwork object in the CNO object named cluster.

Cluster Network Operator configuration object

The fields for the Cluster Network Operator (CNO) are described in the following table:

Table 1. Cluster Network Operator configuration object
Field Type Description

metadata.name

string

The name of the CNO object. This name is always cluster.

spec.clusterNetwork

array

A list specifying the blocks of IP addresses from which pod IP addresses are allocated and the subnet prefix length assigned to each individual node in the cluster. For example:

spec:
  clusterNetwork:
  - cidr: 10.128.0.0/19
    hostPrefix: 23
  - cidr: 10.128.32.0/19
    hostPrefix: 23

spec.serviceNetwork

array

A block of IP addresses for services. The OVN-Kubernetes network plugin supports only a single IP address block for the service network. For example:

spec:
  serviceNetwork:
  - 172.30.0.0/14

You can customize this field only in the install-config.yaml file before you create the manifests. The value is read-only in the manifest file.

spec.defaultNetwork

object

Configures the network plugin for the cluster network.

spec.additionalRoutingCapabilities.providers

array

This setting enables a dynamic routing provider. The FRR routing capability provider is required for the route advertisement feature. The only supported value is FRR.

  • FRR: The FRR routing provider

spec:
  additionalRoutingCapabilities:
    providers:
    - FRR

Important

For a cluster that needs to deploy objects across multiple networks, ensure that you specify the same value for the clusterNetwork.hostPrefix parameter for each network type that is defined in the install-config.yaml file. Setting a different value for each clusterNetwork.hostPrefix parameter can impact the OVN-Kubernetes network plugin, where the plugin cannot effectively route object traffic among different nodes.

defaultNetwork object configuration

The values for the defaultNetwork object are defined in the following table:

Table 2. defaultNetwork object
Field Type Description

type

string

OVNKubernetes. The Red Hat OpenShift Networking network plugin is selected during installation. This value cannot be changed after cluster installation.

Note

OpenShift Container Platform uses the OVN-Kubernetes network plugin by default.

ovnKubernetesConfig

object

This object is only valid for the OVN-Kubernetes network plugin.

Configuration for the OVN-Kubernetes network plugin

The following table describes the configuration fields for the OVN-Kubernetes network plugin:

Table 3. ovnKubernetesConfig object
Field Type Description

mtu

integer

The maximum transmission unit (MTU) for the Geneve (Generic Network Virtualization Encapsulation) overlay network. This is detected automatically based on the MTU of the primary network interface. You do not normally need to override the detected MTU.

If the auto-detected value is not what you expect it to be, confirm that the MTU on the primary network interface on your nodes is correct. You cannot use this option to change the MTU value of the primary network interface on the nodes.

If your cluster requires different MTU values for different nodes, you must set this value to 100 less than the lowest MTU value in your cluster. For example, if some nodes in your cluster have an MTU of 9001, and some have an MTU of 1500, you must set this value to 1400.

genevePort

integer

The port to use for all Geneve packets. The default value is 6081. This value cannot be changed after cluster installation.

ipsecConfig

object

Specify a configuration object for customizing the IPsec configuration.

ipv4

object

Specifies a configuration object for IPv4 settings.

ipv6

object

Specifies a configuration object for IPv6 settings.

policyAuditConfig

object

Specify a configuration object for customizing network policy audit logging. If unset, the defaults audit log settings are used.

routeAdvertisements

string

Specifies whether to advertise cluster network routes. The default value is Disabled.

  • Enabled: Import routes to the cluster network and advertise cluster network routes as configured in RouteAdvertisements objects.

  • Disabled: Do not import routes to the cluster network or advertise cluster network routes.

gatewayConfig

object

Optional: Specify a configuration object for customizing how egress traffic is sent to the node gateway. Valid values are Shared and Local. The default value is Shared. In the default setting, the Open vSwitch (OVS) outputs traffic directly to the node IP interface. In the Local setting, it traverses the host network; consequently, it gets applied to the routing table of the host.

Note

While migrating egress traffic, you can expect some disruption to workloads and service traffic until the Cluster Network Operator (CNO) successfully rolls out the changes.
Table 4. ovnKubernetesConfig.ipv4 object
Field Type Description

internalTransitSwitchSubnet

string

If your existing network infrastructure overlaps with the 100.88.0.0/16 IPv4 subnet, you can specify a different IP address range for internal use by OVN-Kubernetes. The subnet for the distributed transit switch that enables east-west traffic. This subnet cannot overlap with any other subnets used by OVN-Kubernetes or on the host itself. It must be large enough to accommodate one IP address per node in your cluster.

The default value is 100.88.0.0/16.

internalJoinSubnet

string

If your existing network infrastructure overlaps with the 100.64.0.0/16 IPv4 subnet, you can specify a different IP address range for internal use by OVN-Kubernetes. You must ensure that the IP address range does not overlap with any other subnet used by your OpenShift Container Platform installation. The IP address range must be larger than the maximum number of nodes that can be added to the cluster. For example, if the clusterNetwork.cidr value is 10.128.0.0/14 and the clusterNetwork.hostPrefix value is /23, then the maximum number of nodes is 2^(23-14)=512.

The default value is 100.64.0.0/16.
Table 5. ovnKubernetesConfig.ipv6 object
Field Type Description

internalTransitSwitchSubnet

string

If your existing network infrastructure overlaps with the fd97::/64 IPv6 subnet, you can specify a different IP address range for internal use by OVN-Kubernetes. The subnet for the distributed transit switch that enables east-west traffic. This subnet cannot overlap with any other subnets used by OVN-Kubernetes or on the host itself. It must be large enough to accommodate one IP address per node in your cluster.

The default value is fd97::/64.

internalJoinSubnet

string

If your existing network infrastructure overlaps with the fd98::/64 IPv6 subnet, you can specify a different IP address range for internal use by OVN-Kubernetes. You must ensure that the IP address range does not overlap with any other subnet used by your OpenShift Container Platform installation. The IP address range must be larger than the maximum number of nodes that can be added to the cluster.

The default value is fd98::/64.
Table 6. policyAuditConfig object
Field Type Description

rateLimit

integer

The maximum number of messages to generate every second per node. The default value is 20 messages per second.

maxFileSize

integer

The maximum size for the audit log in bytes. The default value is 50000000 or 50 MB.

maxLogFiles

integer

The maximum number of log files that are retained.

destination

string

One of the following additional audit log targets:

libc

The libc syslog() function of the journald process on the host.

udp:<host>:<port>

A syslog server. Replace <host>:<port> with the host and port of the syslog server.

unix:<file>

A Unix Domain Socket file specified by <file>.

null

Do not send the audit logs to any additional target.

syslogFacility

string

The syslog facility, such as kern, as defined by RFC5424. The default value is local0.
Table 7. gatewayConfig object
Field Type Description

routingViaHost

boolean

Set this field to true to send egress traffic from pods to the host networking stack. For highly-specialized installations and applications that rely on manually configured routes in the kernel routing table, you might want to route egress traffic to the host networking stack. By default, egress traffic is processed in OVN to exit the cluster and is not affected by specialized routes in the kernel routing table. The default value is false.

This field has an interaction with the Open vSwitch hardware offloading feature. If you set this field to true, you do not receive the performance benefits of the offloading because egress traffic is processed by the host networking stack.

ipForwarding

object

You can control IP forwarding for all traffic on OVN-Kubernetes managed interfaces by using the ipForwarding specification in the Network resource. Specify Restricted to only allow IP forwarding for Kubernetes related traffic. Specify Global to allow forwarding of all IP traffic. For new installations, the default is Restricted. For updates to OpenShift Container Platform 4.14 or later, the default is Global.

Note

The default value of Restricted sets the IP forwarding to drop.

ipv4

object

Optional: Specify an object to configure the internal OVN-Kubernetes masquerade address for host to service traffic for IPv4 addresses.

ipv6

object

Optional: Specify an object to configure the internal OVN-Kubernetes masquerade address for host to service traffic for IPv6 addresses.
Table 8. gatewayConfig.ipv4 object
Field Type Description

internalMasqueradeSubnet

string

The masquerade IPv4 addresses that are used internally to enable host to service traffic. The host is configured with these IP addresses as well as the shared gateway bridge interface. The default value is 169.254.169.0/29.

Important

For OpenShift Container Platform 4.17 and later versions, clusters use 169.254.0.0/17 as the default masquerade subnet. For upgraded clusters, there is no change to the default masquerade subnet.
Table 9. gatewayConfig.ipv6 object
Field Type Description

internalMasqueradeSubnet

string

The masquerade IPv6 addresses that are used internally to enable host to service traffic. The host is configured with these IP addresses as well as the shared gateway bridge interface. The default value is fd69::/125.

Important

For OpenShift Container Platform 4.17 and later versions, clusters use fd69::/112 as the default masquerade subnet. For upgraded clusters, there is no change to the default masquerade subnet.
Table 10. ipsecConfig object
Field Type Description

mode

string

Specifies the behavior of the IPsec implementation. Must be one of the following values:

  • Disabled: IPsec is not enabled on cluster nodes.

  • External: IPsec is enabled for network traffic with external hosts.

  • Full: IPsec is enabled for pod traffic and network traffic with external hosts.
Example OVN-Kubernetes configuration with IPSec enabled
defaultNetwork:
  type: OVNKubernetes
  ovnKubernetesConfig:
    mtu: 1400
    genevePort: 6081
    ipsecConfig:
      mode: Full

Creating the Kubernetes manifest and Ignition config files

To customize cluster definitions and manually start machines, generate the Kubernetes manifest and Ignition config files. These assets provide the necessary instructions to configure the cluster infrastructure according to your specific deployment requirements.

The installation configuration file transforms into the Kubernetes manifests. The manifests wrap into the Ignition configuration files, which are later used to configure the cluster machines.

Important

  • The Ignition config files that the OpenShift Container Platform installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending node-bootstrapper certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information.

  • It is recommended that you use Ignition config files within 12 hours after they are generated because the 24-hour certificate rotates from 16 to 22 hours after the cluster is installed. By using the Ignition config files within 12 hours, you can avoid installation failure if the certificate update runs during installation.

Note

The installation program that generates the manifest and Ignition files is architecture specific and can be obtained from the client image mirror. The Linux version of the installation program runs on s390x only. This installer program is also available as a macOS version.

Prerequisites

  • You obtained the OpenShift Container Platform installation program. For a restricted network installation, these files are on your mirror host.

  • You created the install-config.yaml installation configuration file.

Procedure

  1. Change to the directory that contains the OpenShift Container Platform installation program and generate the Kubernetes manifests for the cluster:

    $ ./openshift-install create manifests --dir <installation_directory>

    where

    <installation_directory>

    Specifies the installation directory that contains the install-config.yaml file you created.

    Warning

    If you are installing a three-node cluster, skip the following step to allow the control plane nodes to be schedulable.

    +

    Important

    When you configure control plane nodes from the default unschedulable to schedulable, additional subscriptions are required. This is because control plane nodes then become compute nodes.

  2. Check that the mastersSchedulable parameter in the <installation_directory>/manifests/cluster-scheduler-02-config.yml Kubernetes manifest file is set to false. This setting prevents pods from being scheduled on the control plane machines:

    1. Open the <installation_directory>/manifests/cluster-scheduler-02-config.yml file.

    2. Locate the mastersSchedulable parameter and ensure that it is set to false.

    3. Save and exit the file.

  3. To create the Ignition configuration files, run the following command from the directory that contains the installation program:

    $ ./openshift-install create ignition-configs --dir <installation_directory>

    where:

    <installation_directory>

    Specifies the same installation directory.

    Ignition config files are created for the bootstrap, control plane, and compute nodes in the installation directory. The kubeadmin-password and kubeconfig files are created in the ./<installation_directory>/auth directory:

    .
├── auth
│   ├── kubeadmin-password
│   └── kubeconfig
├── bootstrap.ign
├── master.ign
├── metadata.json
└── worker.ign

Installing RHCOS and starting the OpenShift Container Platform bootstrap process

To install OpenShift Container Platform on IBM Z® infrastructure that you provision, you must install Red Hat Enterprise Linux CoreOS (RHCOS) as Red Hat Enterprise Linux (RHEL) guest virtual machines. When you install RHCOS, you must provide the Ignition config file that was generated by the OpenShift Container Platform installation program for the type of machine you are installing. If you have configured suitable networking, DNS, and load balancing infrastructure, the OpenShift Container Platform bootstrap process begins automatically after the RHCOS machines have rebooted.

You can perform a fast-track installation of RHCOS that uses a prepackaged QEMU copy-on-write (QCOW2) disk image. Alternatively, you can perform a full installation on a new QCOW2 disk image.

To add further security to your system, you can optionally install RHCOS using IBM® Secure Execution before proceeding to the fast-track installation.

Configuring encryption for nodes in an IBM Z or IBM LinuxONE environment

You can choose between three methods to optionally secure your OpenShift Container Platform control plane and compute nodes on IBM Z® or IBM® LinuxONE:

  • IBM® Secure Execution

  • Linux Unified Key Setup (LUKS) encryption via IBM® Crypto Express (CEX)

  • Network Bound Disk Encryption (NBDE)

Installing RHCOS using IBM Secure Execution

Before you install RHCOS using IBM® Secure Execution, you must prepare the underlying infrastructure.

Prerequisites

  • IBM® z15 or later, or IBM® LinuxONE III or later.

  • Red Hat Enterprise Linux (RHEL) 8 or later.

  • You have a bootstrap Ignition file. The file is not protected, enabling others to view and edit it.

  • You have verified that the boot image has not been altered after installation.

  • You must run all your nodes as IBM® Secure Execution guests.

Procedure

  1. Prepare your RHEL KVM host to support IBM® Secure Execution.

    • By default, KVM hosts do not support guests in IBM® Secure Execution mode. To support guests in IBM® Secure Execution mode, KVM hosts must boot in LPAR mode with the kernel parameter specification prot_virt=1. To enable prot_virt=1 on RHEL 8, follow these steps:

      1. Navigate to /boot/loader/entries/ to modify your bootloader configuration file *.conf.

      2. Add the kernel command line parameter prot_virt=1.

      3. Run the zipl command and reboot your system.

        KVM hosts that successfully start with support for IBM® Secure Execution for Linux issue the following kernel message:

        prot_virt: Reserving <amount>MB as ultravisor base storage.

      4. To verify that the KVM host now supports IBM® Secure Execution, run the following command:

        # cat /sys/firmware/uv/prot_virt_host
        Example output
        1

        The value of this attribute is 1 for Linux instances that detect their environment as consistent with that of a secure host. For other instances, the value is 0.

  2. Add your host keys to the KVM guest via Ignition.

    During the first boot, RHCOS looks for your host keys to re-encrypt itself with them. RHCOS searches for files starting with ibm-z-hostkey- in the /etc/se-hostkeys directory. All host keys, for each machine the cluster is running on, must be loaded into the directory by the administrator. After first boot, you cannot run the VM on any other machines.

    Note

    You need to prepare your Ignition file on a safe system. For example, another IBM® Secure Execution guest.

    For example:

    {
  "ignition": { "version": "3.0.0" },
  "storage": {
    "files": [
      {
        "path": "/etc/se-hostkeys/ibm-z-hostkey-<your-hostkey>.crt",
        "contents": {
          "source": "data:;base64,<base64 encoded hostkey document>"
        },
        "mode": 420
      },
      {
        "path": "/etc/se-hostkeys/ibm-z-hostkey-<your-hostkey>.crt",
        "contents": {
          "source": "data:;base64,<base64 encoded hostkey document>"
        },
        "mode": 420
      }
    ]
  }
}
```

    Note

    You can add as many host keys as required if you want your node to be able to run on multiple IBM Z® machines.

  3. To generate the Base64 encoded string, run the following command:

    base64 <your-hostkey>.crt

    Compared to guests not running IBM® Secure Execution, the first boot of the machine is longer because the entire image is encrypted with a randomly generated LUKS passphrase before the Ignition phase.

  4. Add Ignition protection

    To protect the secrets that are stored in the Ignition config file from being read or even modified, you must encrypt the Ignition config file.

    Note

    To achieve the desired security, Ignition logging and local login are disabled by default when running IBM® Secure Execution.

    1. Fetch the public GPG key for the secex-qemu.qcow2 image and encrypt the Ignition config with the key by running the following command:

      gpg --recipient-file /path/to/ignition.gpg.pub --yes --output /path/to/config.ign.gpg --verbose --armor --encrypt /path/to/config.ign

  5. Follow the fast-track installation of RHCOS to install nodes by using the IBM® Secure Execution QCOW image.

    Note

    Before you start the VM, replace serial=ignition with serial=ignition_crypted, and add the launchSecurity parameter.

Verification

When you have completed the fast-track installation of RHCOS and Ignition runs at the first boot, verify if decryption is successful.

  • If the decryption is successful, you can expect an output similar to the following example:

    Example output
    [    2.801433] systemd[1]: Starting coreos-ignition-setup-user.service - CoreOS Ignition User Config Setup...

[    2.803959] coreos-secex-ignition-decrypt[731]: gpg: key <key_name>: public key "Secure Execution (secex) 38.20230323.dev.0" imported
[    2.808874] coreos-secex-ignition-decrypt[740]: gpg: encrypted with rsa4096 key, ID <key_name>, created <yyyy-mm-dd>
[  OK  ] Finished coreos-secex-igni…S Secex Ignition Config Decryptor.

  • If the decryption fails, you can expect an output similar to the following example:

    Example output
    Starting coreos-ignition-s…reOS Ignition User Config Setup...
[    2.863675] coreos-secex-ignition-decrypt[729]: gpg: key <key_name>: public key "Secure Execution (secex) 38.20230323.dev.0" imported
[    2.869178] coreos-secex-ignition-decrypt[738]: gpg: encrypted with RSA key, ID <key_name>
[    2.870347] coreos-secex-ignition-decrypt[738]: gpg: public key decryption failed: No secret key
[    2.870371] coreos-secex-ignition-decrypt[738]: gpg: decryption failed: No secret key
Additional resources

LUKS encryption via CEX in an IBM Z or IBM LinuxONE environment

Enabling hardware-based Linux Unified Key Setup (LUKS) encryption via IBM® Crypto Express (CEX) in an IBM Z® or IBM® LinuxONE environment requires additional steps, which are described in detail in this section.

Prerequisites

  • You have installed the butane utility.

  • You have reviewed the instructions for how to create machine configs with Butane.

Procedure

  1. Create Butane configuration files for the control plane and compute nodes:

    • Create a file named main-storage.bu by using the following Butane configuration for a control plane node with disk encryption, for example:

      variant: openshift
version: 4.19.0
metadata:
  name: main-storage
  labels:
    machineconfiguration.openshift.io/role: master
boot_device:
  layout: s390x-virt
  luks:
    cex:
      enabled: true
openshift:
  fips: true 
  kernel_arguments:
    - rd.luks.key=/etc/luks/cex.key
      1. Specifies whether to enable or disable FIPS mode. By default, FIPS mode is not enabled. If FIPS mode is enabled, the Red Hat Enterprise Linux CoreOS (RHCOS) machines that OpenShift Container Platform runs on bypass the default Kubernetes cryptography suite and use the cryptography modules that are provided with RHCOS instead.
      2. Specifies the location of the key that is required to decrypt the device. You can not change this value.

  2. Create a parameter file that includes ignition.platform.id=metal and ignition.firstboot.

    Example kernel parameter file for the control plane machine
    cio_ignore=all,!condev rd.neednet=1 \
console=ttysclp0 \
ignition.firstboot ignition.platform.id=metal \
coreos.inst.ignition_url=http://<http_server>/master.ign \
coreos.live.rootfs_url=http://<http_server>/rhcos-<version>-live-rootfs.<architecture>.img \
ip=<ip_address>::<gateway>:<netmask>:<hostname>::none nameserver=<dns> \
rd.znet=qeth,0.0.bdd0,0.0.bdd1,0.0.bdd2,layer2=1 \
rd.zfcp=0.0.5677,0x600606680g7f0056,0x034F000000000000
    1. Specifies the location of the Ignition configuration file. Use master.ign or worker.ign. You can only use the HTTP and HTTPS protocols.
    2. Specifies the location of the rootfs artifact for the kernel and initramfs that you want to boot. You can only use the HTTP and HTTPS protocols.

      Note

      Write all options in the parameter file as a single line and make sure you have no newline characters.

Configuring NBDE with static IP in an IBM Z or IBM LinuxONE environment

Enabling NBDE disk encryption in an IBM Z® or IBM® LinuxONE environment requires additional steps, which are described in detail in this section.

Prerequisites

  • You have set up the External Tang Server. See Network-bound disk encryption for instructions.

  • You have installed the butane utility.

  • You have reviewed the instructions for how to create machine configs with Butane.

Procedure

  1. Create Butane configuration files for the control plane and compute nodes.

    The following example of a Butane configuration for a control plane node creates a file named master-storage.bu for disk encryption:

    variant: openshift
version: 4.19.0
metadata:
  name: master-storage
  labels:
    machineconfiguration.openshift.io/role: master
storage:
  luks:
    - clevis:
        tang:
          - thumbprint: QcPr_NHFJammnRCA3fFMVdNBwjs
            url: http://clevis.example.com:7500
      device: /dev/disk/by-partlabel/root
      label: luks-root
      name: root
      wipe_volume: true
  filesystems:
    - device: /dev/mapper/root
      format: xfs
      label: root
      wipe_filesystem: true
openshift:
  fips: true
    1. Whether to enable or disable FIPS mode. By default, FIPS mode is not enabled. If FIPS mode is enabled, the Red Hat Enterprise Linux CoreOS (RHCOS) machines that OpenShift Container Platform runs on bypass the default Kubernetes cryptography suite and use the cryptography modules that are provided with RHCOS instead.

  2. Create a customized initramfs file to boot the machine, by running the following command:

    $ coreos-installer pxe customize \
    /root/rhcos-bootfiles/rhcos-<release>-live-initramfs.s390x.img \
    --dest-device /dev/disk/by-id/scsi-<serial_number> --dest-karg-append \
    ip=<ip_address>::<gateway_ip>:<subnet_mask>::<network_device>:none \
    --dest-karg-append nameserver=<nameserver_ip> \
    --dest-karg-append rd.neednet=1 -o \
    /root/rhcos-bootfiles/<node_name>-initramfs.s390x.img

    Note

    Before first boot, you must customize the initramfs for each node in the cluster, and add PXE kernel parameters.

  3. Create a parameter file that includes ignition.platform.id=metal and ignition.firstboot.

    Example kernel parameter file for the control plane machine
    cio_ignore=all,!condev rd.neednet=1 \
console=ttysclp0 \
ignition.firstboot ignition.platform.id=metal \
coreos.inst.ignition_url=http://<http_server>/master.ign \
coreos.live.rootfs_url=http://<http_server>/rhcos-<version>-live-rootfs.<architecture>.img \
ip=<ip>::<gateway>:<netmask>:<hostname>::none nameserver=<dns> \
rd.znet=qeth,0.0.bdd0,0.0.bdd1,0.0.bdd2,layer2=1 \
rd.zfcp=0.0.5677,0x600606680g7f0056,0x034F000000000000 \
zfcp.allow_lun_scan=0
    1. Specify the location of the Ignition config file. Use master.ign or worker.ign. Only HTTP and HTTPS protocols are supported.
    2. Specify the location of the rootfs artifact for the kernel and initramfs you are booting. Only HTTP and HTTPS protocols are supported.

    Note

    Write all options in the parameter file as a single line and make sure you have no newline characters.

Additional resources

Fast-track installation by using a prepackaged QCOW2 disk image

Complete the following steps to create the machines in a fast-track installation of Red Hat Enterprise Linux CoreOS (RHCOS), importing a prepackaged Red Hat Enterprise Linux CoreOS (RHCOS) QEMU copy-on-write (QCOW2) disk image.

Prerequisites

  • At least one LPAR running on RHEL 8.6 or later with KVM, referred to as RHEL KVM host in this procedure.

  • The KVM/QEMU hypervisor is installed on the RHEL KVM host.

  • A domain name server (DNS) that can perform hostname and reverse lookup for the nodes.

  • A DHCP server that provides IP addresses.

Procedure

  1. Obtain the RHEL QEMU copy-on-write (QCOW2) disk image file from the Product Downloads page on the Red Hat Customer Portal or from the RHCOS image mirror page.

    Important

    The RHCOS images might not change with every release of OpenShift Container Platform. You must download images with the highest version that is less than or equal to the OpenShift Container Platform version that you install. Only use the appropriate RHCOS QCOW2 image described in the following procedure.

  2. Download the QCOW2 disk image and Ignition files to a common directory on the RHEL KVM host.

    For example: /var/lib/libvirt/images

    Note

    The Ignition files are generated by the OpenShift Container Platform installer.

  3. Create a new disk image with the QCOW2 disk image backing file for each KVM guest node.

    $ qemu-img create -f qcow2 -F qcow2 -b /var/lib/libvirt/images/{source_rhcos_qemu} /var/lib/libvirt/images/{vmname}.qcow2 {size}

  4. Create the new KVM guest nodes using the Ignition file and the new disk image.

    $ virt-install --noautoconsole \
   --connect qemu:///system \
   --name <vm_name> \
   --memory <memory_mb> \
   --vcpus <vcpus> \
   --disk <disk> \
   --launchSecurity type="s390-pv" \ 
   --import \
   --network network=<virt_network_parm>,mac=<mac_address> \
   --disk path=<ign_file>,format=raw,readonly=on,serial=ignition,startup_policy=optional
    1. If IBM® Secure Execution is enabled, add the launchSecurity type="s390-pv" parameter.
    2. If IBM® Secure Execution is enabled, replace serial=ignition with serial=ignition_crypted.

Full installation on a new QCOW2 disk image

Complete the following steps to create the machines in a full installation on a new QEMU copy-on-write (QCOW2) disk image.

Prerequisites

  • At least one LPAR running on RHEL 8.6 or later with KVM, referred to as RHEL KVM host in this procedure.

  • The KVM/QEMU hypervisor is installed on the RHEL KVM host.

  • A domain name server (DNS) that can perform hostname and reverse lookup for the nodes.

  • An HTTP or HTTPS server is set up.

Procedure

  1. Obtain the RHEL kernel, initramfs, and rootfs files from the Product Downloads page on the Red Hat Customer Portal or from the RHCOS image mirror page.

    Important

    The RHCOS images might not change with every release of OpenShift Container Platform. You must download images with the highest version that is less than or equal to the OpenShift Container Platform version that you install. Only use the appropriate RHCOS QCOW2 image described in the following procedure.

    The file names contain the OpenShift Container Platform version number. They resemble the following examples:

    • kernel: rhcos-<version>-live-kernel-<architecture>

    • initramfs: rhcos-<version>-live-initramfs.<architecture>.img

    • rootfs: rhcos-<version>-live-rootfs.<architecture>.img

  2. Move the downloaded RHEL live kernel, initramfs, and rootfs as well as the Ignition files to an HTTP or HTTPS server before you launch virt-install.

    Note

    The Ignition files are generated by the OpenShift Container Platform installer.

  3. Create the new KVM guest nodes using the RHEL kernel, initramfs, and Ignition files, the new disk image, and adjusted parm line arguments.

    $ virt-install \
   --connect qemu:///system \
   --name <vm_name> \
   --memory <memory_mb> \
   --vcpus <vcpus> \
   --location <media_location>,kernel=<rhcos_kernel>,initrd=<rhcos_initrd> \ / 
   --disk <vm_name>.qcow2,size=<image_size>,cache=none,io=native \
   --network network=<virt_network_parm> \
   --boot hd \
   --extra-args "rd.neednet=1" \
   --extra-args "coreos.inst.install_dev=/dev/<block_device>" \
   --extra-args "coreos.inst.ignition_url=http://<http_server>/bootstrap.ign" \
   --extra-args "coreos.live.rootfs_url=http://<http_server>/rhcos-<version>-live-rootfs.<architecture>.img" \
   --extra-args "ip=<ip>::<gateway>:<netmask>:<hostname>::none nameserver=<dns>" \
   --noautoconsole \
   --wait
    1. For the --location parameter, specify the location of the kernel/initrd on the HTTP or HTTPS server.
    2. Specify the location of the Ignition config file. Use bootstrap.ign, master.ign, or worker.ign. Only HTTP and HTTPS protocols are supported.
    3. Specify the location of the rootfs artifact for the kernel and initramfs you are booting. Only HTTP and HTTPS protocols are supported.

Networking options for ISO installations

You can configure advanced options so that you can modify the Red Hat Enterprise Linux CoreOS (RHCOS) manual installation process. The subsequent sections show examples of networking options for an ISO installation.

If you install RHCOS from an ISO image, you can add kernel arguments manually when you boot the image to configure networking for a node. If no networking arguments are specified, DHCP is activated in the initramfs when RHCOS detects that networking is required to fetch the Ignition config file.

Important

When adding networking arguments manually, you must also add the rd.neednet=1 kernel argument to bring the network up in the initramfs.

The following information provides examples for configuring networking on your RHCOS nodes for ISO installations. The examples describe how to use the ip= and nameserver= kernel arguments.

Note

Ordering is important when adding the kernel arguments: ip= and nameserver=.

The networking options are passed to the dracut tool during system boot. For more information about the networking options supported by dracut, see the dracut.cmdline manual page.

Additional resources

Configuring DHCP or static IP addresses

You can configure an IP address by using either DHCP or an individual static IP address. If you set a static IP, you must then identify the DNS server IP address on each node.

The configuration examples in the procedure, update the IP addresses for the following components:

  • The node’s IP address to 10.10.10.2

  • The gateway address to 10.10.10.254

  • The netmask to 255.255.255.0

  • The hostname to core0.example.com

  • The DNS server address to 4.4.4.41

  • The auto-configuration value to none. No auto-configuration is required when IP networking is configured statically.

Procedure

  1. Enter a command like the following command to configure a static IP address:

    ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none
nameserver=4.4.4.41

  2. Enter a command like the following command to configure a DHCP IP address:

    ip=enp1s0:dhcp

    Note

    When you use DHCP to configure IP addressing for the RHCOS machines, the machines also obtain the DNS server information through DHCP. For DHCP-based deployments, you can define the DNS server address that is used by the RHCOS nodes through your DHCP server configuration.

  3. If two or more network interfaces and only one interface exists, disable DHCP on a single interface. In the example, the enp1s0 interface has a static networking configuration and DHCP is disabled for enp2s0, which is not used:

    ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none
ip=::::core0.example.com:enp2s0:none

  4. If you need to combine DHCP and static IP configurations on systems with multiple network interfaces, run the following example command:

    ip=enp1s0:dhcp
ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp2s0:none

Configuring an IP address without a static hostname

You can configure an IP address without assigning a static hostname. If a static hostname is not set by the user, the static hostname gets picked up and automatically set by a reverse DNS lookup.

The configuration examples in the procedure, update the IP addresses for the following components:

  • The node’s IP address to 10.10.10.2

  • The gateway address to 10.10.10.254

  • The netmask to 255.255.255.0

  • The DNS server address to 4.4.4.41

  • The auto-configuration value to none. No auto-configuration is required when IP networking is configured statically.

Procedure

  • To configure an IP address without a static hostname, enter a command like the following command:

    ip=10.10.10.2::10.10.10.254:255.255.255.0::enp1s0:none
nameserver=4.4.4.41

Specifying multiple network interfaces and DNS servers

You can specify multiple network interfaces by setting multiple ip= entries. You can provide multiple DNS servers by adding a nameserver= entry for each server,

Procedure

  • To specify multiple network interfaces for your interfaces, you can enter a command like the following command:

    ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none
ip=10.10.10.3::10.10.10.254:255.255.255.0:core0.example.com:enp2s0:none

  • To provide multiple DNS servers by adding a nameserver= entry for each server, enter a command like the following command:

    nameserver=1.1.1.1
nameserver=8.8.8.8

Configuring default gateway and route

As an optional task, you can configure routes to additional networks by setting an rd.route= value.

Note

When you configure one or multiple networks, one default gateway is required. If the additional network gateway is different from the primary network gateway, the default gateway must be the primary network gateway.

Procedure

  • To configure the default gateway, enter the following command:

    ip=::10.10.10.254::::

  • To configure the route for an additional network, enter the following command:

    rd.route=20.20.20.0/24:20.20.20.254:enp2s0

Configuring VLANs on individual interfaces

As an optional task, you can configure VLANs on individual interfaces by using the vlan= parameter.

Procedure

  • To configure a VLAN on a network interface and use a static IP address, run the following command:

    ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp2s0.100:none
vlan=enp2s0.100:enp2s0

  • To configure a VLAN on a network interface and to use DHCP, run the following command:

    ip=enp2s0.100:dhcp
vlan=enp2s0.100:enp2s0

Waiting for the bootstrap process to complete

To install OpenShift Container Platform, use Ignition configuration files to initialize the bootstrap process after the cluster nodes boot into RHCOS. You must wait for this process to complete to ensure the cluster is fully installed.

Prerequisites

  • You have created the Ignition config files for your cluster.

  • You have configured suitable network, DNS, and load balancing infrastructure.

  • You have obtained the installation program and generated the Ignition config files for your cluster.

  • You installed RHCOS on your cluster machines and provided the Ignition config files that the OpenShift Container Platform installation program generated.

Procedure

  1. Monitor the bootstrap process:

    $ ./openshift-install --dir <installation_directory> wait-for bootstrap-complete \
    --log-level=info

    where:

    <installation_directory>

    Specifies the path to the directory that stores the installation files.

    --log-level=info

    Specifies warn, debug, or error instead of info to view different installation details.

    Example output
    INFO Waiting up to 30m0s for the Kubernetes API at https://api.test.example.com:6443...
INFO API v1.34.2 up
INFO Waiting up to 30m0s for bootstrapping to complete...
INFO It is now safe to remove the bootstrap resources

    The command succeeds when the Kubernetes API server signals that it has been bootstrapped on the control plane machines.

  2. After the bootstrap process is complete, remove the bootstrap machine from the load balancer.

    Important

    You must remove the bootstrap machine from the load balancer at this point. You can also remove or reformat the bootstrap machine itself.

Logging in to the cluster by using the CLI

To log in to your cluster as the default system user, export the kubeconfig file. This configuration enables the CLI to authenticate and connect to the specific API server created during OpenShift Container Platform installation.

The kubeconfig file is specific to a cluster and is created during OpenShift Container Platform installation.

Prerequisites

  • You deployed an OpenShift Container Platform cluster.

  • You installed the OpenShift CLI (oc).

Procedure

  1. Export the kubeadmin credentials by running the following command:

    $ export KUBECONFIG=<installation_directory>/auth/kubeconfig

    where:

    <installation_directory>

    Specifies the path to the directory that stores the installation files.

  2. Verify you can run oc commands successfully using the exported configuration by running the following command:

    $ oc whoami
    Example output
    system:admin

Approving the certificate signing requests for your machines

To add machines to a cluster, verify the status of the certificate signing requests (CSRs) generated for each machine. If manual approval is required, approve the client requests first, followed by the server requests.

Prerequisites

  • You added machines to your cluster.

Procedure

  1. Confirm that the cluster recognizes the machines:

    $ oc get nodes
    Example output
    NAME      STATUS    ROLES   AGE  VERSION
master-0  Ready     master  63m  v1.34.2
master-1  Ready     master  63m  v1.34.2
master-2  Ready     master  64m  v1.34.2

    The output lists all of the machines that you created.

    Note

    The preceding output might not include the compute nodes, also known as worker nodes, until some CSRs are approved.

  2. Review the pending CSRs and ensure that you see the client requests with the Pending or Approved status for each machine that you added to the cluster:

    $ oc get csr
    Example output
    NAME        AGE     REQUESTOR                                                                   CONDITION
csr-8b2br   15m     system:serviceaccount:openshift-machine-config-operator:node-bootstrapper   Pending
csr-8vnps   15m     system:serviceaccount:openshift-machine-config-operator:node-bootstrapper   Pending
...

    In this example, two machines are joining the cluster. You might see more approved CSRs in the list.

  3. If the CSRs were not approved, after all of the pending CSRs for the machines you added are in Pending status, approve the CSRs for your cluster machines:

    Note

    Because the CSRs rotate automatically, approve your CSRs within an hour of adding the machines to the cluster. If you do not approve them within an hour, the certificates will rotate, and more than two certificates will be present for each node. You must approve all of these certificates. After the client CSR is approved, the Kubelet creates a secondary CSR for the serving certificate, which requires manual approval. Then, subsequent serving certificate renewal requests are automatically approved by the machine-approver if the Kubelet requests a new certificate with identical parameters.

    Note

    For clusters running on platforms that are not machine API enabled, such as bare metal and other user-provisioned infrastructure, you must implement a method of automatically approving the kubelet serving certificate requests (CSRs). If a request is not approved, then the oc exec, oc rsh, and oc logs commands cannot succeed, because a serving certificate is required when the API server connects to the kubelet. Any operation that contacts the Kubelet endpoint requires this certificate approval to be in place. The method must watch for new CSRs, confirm that the CSR was submitted by the node-bootstrapper service account in the system:node or system:admin groups, and confirm the identity of the node.

    • To approve them individually, run the following command for each valid CSR:

      $ oc adm certificate approve <csr_name>

      where:

      <csr_name>

      Specifies the name of a CSR from the list of current CSRs.

    • To approve all pending CSRs, run the following command:

      $ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs --no-run-if-empty oc adm certificate approve

      Note

      Some Operators might not become available until some CSRs are approved.

  4. Now that your client requests are approved, you must review the server requests for each machine that you added to the cluster:

    $ oc get csr
    Example output
    NAME        AGE     REQUESTOR                                                                   CONDITION
csr-bfd72   5m26s   system:node:ip-10-0-50-126.us-east-2.compute.internal                       Pending
csr-c57lv   5m26s   system:node:ip-10-0-95-157.us-east-2.compute.internal                       Pending
...

  5. If the remaining CSRs are not approved, and are in the Pending status, approve the CSRs for your cluster machines:

    • To approve them individually, run the following command for each valid CSR:

      $ oc adm certificate approve <csr_name>

      where:

      <csr_name>

      Specifies the name of a CSR from the list of current CSRs.

    • To approve all pending CSRs, run the following command:

      $ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs oc adm certificate approve

  6. After all client and server CSRs have been approved, the machines have the Ready status. Verify this by running the following command:

    $ oc get nodes
    Example output
    NAME      STATUS    ROLES   AGE  VERSION
master-0  Ready     master  73m  v1.34.2
master-1  Ready     master  73m  v1.34.2
master-2  Ready     master  74m  v1.34.2
worker-0  Ready     worker  11m  v1.34.2
worker-1  Ready     worker  11m  v1.34.2

    Note

    It can take a few minutes after approval of the server CSRs for the machines to transition to the Ready status.

Initial Operator configuration

To ensure all Operators become available, configure the required Operators immediately after the control plane initialises. This configuration is essential for stabilizing the cluster environment following the installation.

Prerequisites

  • Your control plane has initialized.

Procedure

  1. Watch the cluster components come online:

    $ watch -n5 oc get clusteroperators
    Example output
    NAME                                       VERSION   AVAILABLE   PROGRESSING   DEGRADED   SINCE
authentication                             4.19.0    True        False         False      19m
baremetal                                  4.19.0    True        False         False      37m
cloud-credential                           4.19.0    True        False         False      40m
cluster-autoscaler                         4.19.0    True        False         False      37m
config-operator                            4.19.0    True        False         False      38m
console                                    4.19.0    True        False         False      26m
csi-snapshot-controller                    4.19.0    True        False         False      37m
dns                                        4.19.0    True        False         False      37m
etcd                                       4.19.0    True        False         False      36m
image-registry                             4.19.0    True        False         False      31m
ingress                                    4.19.0    True        False         False      30m
insights                                   4.19.0    True        False         False      31m
kube-apiserver                             4.19.0    True        False         False      26m
kube-controller-manager                    4.19.0    True        False         False      36m
kube-scheduler                             4.19.0    True        False         False      36m
kube-storage-version-migrator              4.19.0    True        False         False      37m
machine-api                                4.19.0    True        False         False      29m
machine-approver                           4.19.0    True        False         False      37m
machine-config                             4.19.0    True        False         False      36m
marketplace                                4.19.0    True        False         False      37m
monitoring                                 4.19.0    True        False         False      29m
network                                    4.19.0    True        False         False      38m
node-tuning                                4.19.0    True        False         False      37m
openshift-apiserver                        4.19.0    True        False         False      32m
openshift-controller-manager               4.19.0    True        False         False      30m
openshift-samples                          4.19.0    True        False         False      32m
operator-lifecycle-manager                 4.19.0    True        False         False      37m
operator-lifecycle-manager-catalog         4.19.0    True        False         False      37m
operator-lifecycle-manager-packageserver   4.19.0    True        False         False      32m
service-ca                                 4.19.0    True        False         False      38m
storage                                    4.19.0    True        False         False      37m

  2. Configure the Operators that are not available.

Disabling the default software catalog sources

Operator catalogs that source content provided by Red Hat and community projects are configured for the software catalog by default during an OpenShift Container Platform installation. In a restricted network environment, you must disable the default catalogs as a cluster administrator.

Procedure

  • Disable the sources for the default catalogs by adding disableAllDefaultSources: true to the OperatorHub object:

    $ oc patch OperatorHub cluster --type json \
    -p '[{"op": "add", "path": "/spec/disableAllDefaultSources", "value": true}]'

Tip

Alternatively, you can use the web console to manage catalog sources. From the Administration → Cluster Settings → Configuration → OperatorHub page, click the Sources tab, where you can create, update, delete, disable, and enable individual sources.

Image registry storage configuration

The Image Registry Operator is not initially available for platforms that do not provide default storage. After installation, you must configure your registry to use storage so that the Registry Operator is made available.

Configure a persistent volume, which is required for production clusters. Where applicable, you can configure an empty directory as the storage location for non-production clusters.

You can also allow the image registry to use block storage types by using the Recreate rollout strategy during upgrades.

Configuring registry storage for IBM Z

To ensure the registry is fully operational, configure the registry to use storage immediately after the cluster installation. This configuration is a mandatory step to enable the registry to store data.

Prerequisites

  • You have access to the cluster as a user with the cluster-admin role.

  • You have a cluster on IBM Z®.

  • You have provisioned persistent storage for your cluster, such as Red Hat OpenShift Data Foundation.

    Important

    OpenShift Container Platform supports ReadWriteOnce access for image registry storage when you have only one replica. ReadWriteOnce access also requires that the registry uses the Recreate rollout strategy. To deploy an image registry that supports high availability with two or more replicas, ReadWriteMany access is required.

  • You must have a system with at least 100Gi capacity.

Procedure

  1. To configure your registry to use storage, change the spec.storage.pvc in the configs.imageregistry/cluster resource.

    Note

    When you use shared storage, review your security settings to prevent outside access.

  2. Verify that you do not have a registry pod:

    $ oc get pod -n openshift-image-registry -l docker-registry=default
    Example output
    No resources found in openshift-image-registry namespace

    Note

    If you do have a registry pod in your output, you do not need to continue with this procedure.

  3. Check the registry configuration:

    $ oc edit configs.imageregistry.operator.openshift.io
    Example output
    storage:
  pvc:
    claim:

    Leave the claim field blank to allow the automatic creation of an image-registry-storage PVC.

  4. Check the clusteroperator status:

    $ oc get clusteroperator image-registry
    Example output
    NAME             VERSION              AVAILABLE   PROGRESSING   DEGRADED   SINCE   MESSAGE
image-registry   4.19                 True        False         False      6h50m

  5. Ensure that your registry is set to managed to enable building and pushing of images.

    • Run:

      $ oc edit configs.imageregistry/cluster

      Then, change the line

      managementState: Removed

      to

      managementState: Managed

Configuring storage for the image registry in non-production clusters

You must configure storage for the Image Registry Operator. For non-production clusters, you can set the image registry to an empty directory. If you do so, all images are lost if you restart the registry.

Procedure

  • To set the image registry storage to an empty directory:

    $ oc patch configs.imageregistry.operator.openshift.io cluster --type merge --patch '{"spec":{"storage":{"emptyDir":{}}}}'

    Warning

    Configure this option only for non-production clusters.

    If you run this command before the Image Registry Operator initializes its components, the oc patch command fails with the following error:

    Error from server (NotFound): configs.imageregistry.operator.openshift.io "cluster" not found

    Wait a few minutes and run the command again.

Completing installation on user-provisioned infrastructure

To finalize the installation on user-provisioned infrastructure, complete the cluster deployment after configuring the Operators. This ensures the cluster is fully operational on the infrastructure that you provide.

Prerequisites

  • Your control plane has initialized.

  • You have completed the initial Operator configuration.

Procedure

  1. Confirm that all the cluster components are online with the following command:

    $ watch -n5 oc get clusteroperators
    Example output
    NAME                                       VERSION   AVAILABLE   PROGRESSING   DEGRADED   SINCE
authentication                             4.19.0    True        False         False      19m
baremetal                                  4.19.0    True        False         False      37m
cloud-credential                           4.19.0    True        False         False      40m
cluster-autoscaler                         4.19.0    True        False         False      37m
config-operator                            4.19.0    True        False         False      38m
console                                    4.19.0    True        False         False      26m
csi-snapshot-controller                    4.19.0    True        False         False      37m
dns                                        4.19.0    True        False         False      37m
etcd                                       4.19.0    True        False         False      36m
image-registry                             4.19.0    True        False         False      31m
ingress                                    4.19.0    True        False         False      30m
insights                                   4.19.0    True        False         False      31m
kube-apiserver                             4.19.0    True        False         False      26m
kube-controller-manager                    4.19.0    True        False         False      36m
kube-scheduler                             4.19.0    True        False         False      36m
kube-storage-version-migrator              4.19.0    True        False         False      37m
machine-api                                4.19.0    True        False         False      29m
machine-approver                           4.19.0    True        False         False      37m
machine-config                             4.19.0    True        False         False      36m
marketplace                                4.19.0    True        False         False      37m
monitoring                                 4.19.0    True        False         False      29m
network                                    4.19.0    True        False         False      38m
node-tuning                                4.19.0    True        False         False      37m
openshift-apiserver                        4.19.0    True        False         False      32m
openshift-controller-manager               4.19.0    True        False         False      30m
openshift-samples                          4.19.0    True        False         False      32m
operator-lifecycle-manager                 4.19.0    True        False         False      37m
operator-lifecycle-manager-catalog         4.19.0    True        False         False      37m
operator-lifecycle-manager-packageserver   4.19.0    True        False         False      32m
service-ca                                 4.19.0    True        False         False      38m
storage                                    4.19.0    True        False         False      37m

    Alternatively, the following command notifies you when all of the clusters are available. The command also retrieves and displays credentials:

    $ ./openshift-install --dir <installation_directory> wait-for install-complete

    where:

    <installation_directory>

    Specifies the path to the directory that you stored the installation files in.

    Example output
    INFO Waiting up to 30m0s for the cluster to initialize...

    The command succeeds when the Cluster Version Operator finishes deploying the OpenShift Container Platform cluster from Kubernetes API server.

    Important

    • The Ignition config files that the installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending node-bootstrapper certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information.

    • It is recommended that you use Ignition config files within 12 hours after they are generated because the 24-hour certificate rotates from 16 to 22 hours after the cluster is installed. By using the Ignition config files within 12 hours, you can avoid installation failure if the certificate update runs during installation.

  2. Confirm that the Kubernetes API server is communicating with the pods.

    1. To view a list of all pods, use the following command:

      $ oc get pods --all-namespaces
      Example output
      NAMESPACE                         NAME                                            READY   STATUS      RESTARTS   AGE
openshift-apiserver-operator      openshift-apiserver-operator-85cb746d55-zqhs8   1/1     Running     1          9m
openshift-apiserver               apiserver-67b9g                                 1/1     Running     0          3m
openshift-apiserver               apiserver-ljcmx                                 1/1     Running     0          1m
openshift-apiserver               apiserver-z25h4                                 1/1     Running     0          2m
openshift-authentication-operator authentication-operator-69d5d8bf84-vh2n8        1/1     Running     0          5m

    2. View the logs for a pod that is listed in the output of the previous command by using the following command:

      $ oc logs <pod_name> -n <namespace>

      where:

      <namespace>

      Specifies the pod name and namespace, as shown in the output of an earlier command.

      If the pod logs display, the Kubernetes API server can communicate with the cluster machines.

  3. For an installation with Fibre Channel Protocol (FCP), additional steps are required to enable multipathing. Do not enable multipathing during installation.

    See "Enabling multipathing with kernel arguments on RHCOS" in the Postinstallation machine configuration tasks documentation for more information.

  4. Register your cluster on the Cluster registration page.

Additional resources

Next steps