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Developing PTP events consumer applications with the REST API v2

When developing consumer applications that make use of Precision Time Protocol (PTP) events on a bare-metal cluster node, you deploy your consumer application in a separate application pod. The consumer application subscribes to PTP events by using the PTP events REST API v2.

Note

The following information provides general guidance for developing consumer applications that use PTP events. A complete events consumer application example is outside the scope of this information.

Additional resources

About the PTP fast event notifications framework

Use the Precision Time Protocol (PTP) fast event REST API v2 to subscribe cluster applications to PTP events that the bare-metal cluster node generates.

Note

The fast events notifications framework uses a REST API for communication. The PTP events REST API v2 is based on the O-RAN O-Cloud Notification API Specification for Event Consumers 4.0 that is available from O-RAN ALLIANCE Specifications.

Retrieving PTP events with the PTP events REST API v2

Applications subscribe to PTP events by using an O-RAN v4 compatible REST API in the producer-side cloud event proxy sidecar. The cloud-event-proxy sidecar container can access the same resources as the primary application container without using any of the resources of the primary application and with no significant latency.

Figure 1. Overview of consuming PTP fast events from the PTP event producer REST API v2
Overview of consuming PTP fast events from the PTP event producer REST API
20 Event is generated on the cluster host

The linuxptp-daemon process in the PTP Operator-managed pod runs as a Kubernetes DaemonSet and manages the various linuxptp processes (ptp4l, phc2sys, and optionally for grandmaster clocks, ts2phc). The linuxptp-daemon passes the event to the UNIX domain socket.

20 Event is passed to the cloud-event-proxy sidecar

The PTP plugin reads the event from the UNIX domain socket and passes it to the cloud-event-proxy sidecar in the PTP Operator-managed pod. cloud-event-proxy delivers the event from the Kubernetes infrastructure to Cloud-Native Network Functions (CNFs) with low latency.

20 Event is published

The cloud-event-proxy sidecar in the PTP Operator-managed pod processes the event and publishes the event by using the PTP events REST API v2.

20 Consumer application requests a subscription and receives the subscribed event

The consumer application sends an API request to the producer cloud-event-proxy sidecar to create a PTP events subscription. Once subscribed, the consumer application listens to the address specified in the resource qualifier and receives and processes the PTP events.

Configuring the PTP fast event notifications publisher

To start using PTP fast event notifications for a network interface in your cluster, you must enable the fast event publisher in the PTP Operator PtpOperatorConfig custom resource (CR) and configure ptpClockThreshold values in a PtpConfig CR that you create.

Prerequisites

  • You have installed the OpenShift Container Platform CLI (oc).

  • You have logged in as a user with cluster-admin privileges.

  • You have installed the PTP Operator.

Procedure

  1. Modify the default PTP Operator config to enable PTP fast events.

    1. Save the following YAML in the ptp-operatorconfig.yaml file:

      apiVersion: ptp.openshift.io/v1
kind: PtpOperatorConfig
metadata:
  name: default
  namespace: openshift-ptp
spec:
  daemonNodeSelector:
    node-role.kubernetes.io/worker: ""
  ptpEventConfig:
    enableEventPublisher: true
      1. Enable PTP fast event notifications by setting enableEventPublisher to true.

    2. Update the PtpOperatorConfig CR:

      $ oc apply -f ptp-operatorconfig.yaml

  2. Create a PtpConfig custom resource (CR) for the PTP enabled interface, and set the required values for ptpClockThreshold and ptp4lOpts. The following YAML illustrates the required values that you must set in the PtpConfig CR:

    spec:
  profile:
  - name: "profile1"
    interface: "enp5s0f0"
    ptp4lOpts: "-2 -s --summary_interval -4" 
    phc2sysOpts: "-a -r -m -n 24 -N 8 -R 16" 
    ptp4lConf: "" 
    ptpClockThreshold: 
      holdOverTimeout: 5
      maxOffsetThreshold: 100
      minOffsetThreshold: -100
    1. Append --summary_interval -4 to use PTP fast events.
    2. Required phc2sysOpts values. -m prints messages to stdout. The linuxptp-daemon DaemonSet parses the logs and generates Prometheus metrics.
    3. Specify a string that contains the configuration to replace the default /etc/ptp4l.conf file. To use the default configuration, leave the field empty.
    4. Optional. If the ptpClockThreshold stanza is not present, default values are used for the ptpClockThreshold fields. The stanza shows default ptpClockThreshold values. The ptpClockThreshold values configure how long after the PTP master clock is disconnected before PTP events are triggered. holdOverTimeout is the time value in seconds before the PTP clock event state changes to FREERUN when the PTP master clock is disconnected. The maxOffsetThreshold and minOffsetThreshold settings configure offset values in nanoseconds that compare against the values for CLOCK_REALTIME (phc2sys) or master offset (ptp4l). When the ptp4l or phc2sys offset value is outside this range, the PTP clock state is set to FREERUN. When the offset value is within this range, the PTP clock state is set to LOCKED.
Additional resources

PTP events REST API v2 consumer application reference

PTP event consumer applications require the following features:

  1. A web service running with a POST handler to receive the cloud native PTP events JSON payload

  2. A createSubscription function to subscribe to the PTP events producer

  3. A getCurrentState function to poll the current state of the PTP events producer

The following example Go snippets illustrate these requirements:

Example PTP events consumer server function in Go
func server() {
  http.HandleFunc("/event", getEvent)
  http.ListenAndServe(":9043", nil)
}

func getEvent(w http.ResponseWriter, req *http.Request) {
  defer req.Body.Close()
  bodyBytes, err := io.ReadAll(req.Body)
  if err != nil {
    log.Errorf("error reading event %v", err)
  }
  e := string(bodyBytes)
  if e != "" {
    processEvent(bodyBytes)
    log.Infof("received event %s", string(bodyBytes))
  }
  w.WriteHeader(http.StatusNoContent)
}
Example PTP events createSubscription function in Go
import (
"github.com/redhat-cne/sdk-go/pkg/pubsub"
"github.com/redhat-cne/sdk-go/pkg/types"
v1pubsub "github.com/redhat-cne/sdk-go/v1/pubsub"
)

// Subscribe to PTP events using v2 REST API
s1,_:=createsubscription("/cluster/node/<node_name>/sync/sync-status/sync-state")
s2,_:=createsubscription("/cluster/node/<node_name>/sync/ptp-status/lock-state")
s3,_:=createsubscription("/cluster/node/<node_name>/sync/gnss-status/gnss-sync-status")
s4,_:=createsubscription("/cluster/node/<node_name>/sync/sync-status/os-clock-sync-state")
s5,_:=createsubscription("/cluster/node/<node_name>/sync/ptp-status/clock-class")

// Create PTP event subscriptions POST
func createSubscription(resourceAddress string) (sub pubsub.PubSub, err error) {
  var status int
  apiPath := "/api/ocloudNotifications/v2/"
  localAPIAddr := "consumer-events-subscription-service.cloud-events.svc.cluster.local:9043" // vDU service API address
  apiAddr := "ptp-event-publisher-service-<node_name>.openshift-ptp.svc.cluster.local:9043" 
  apiVersion := "2.0"

  subURL := &types.URI{URL: url.URL{Scheme: "http",
    Host: apiAddr
    Path: fmt.Sprintf("%s%s", apiPath, "subscriptions")}}
  endpointURL := &types.URI{URL: url.URL{Scheme: "http",
    Host: localAPIAddr,
    Path: "event"}}

  sub = v1pubsub.NewPubSub(endpointURL, resourceAddress, apiVersion)
  var subB []byte

  if subB, err = json.Marshal(&sub); err == nil {
    rc := restclient.New()
    if status, subB = rc.PostWithReturn(subURL, subB); status != http.StatusCreated {
      err = fmt.Errorf("error in subscription creation api at %s, returned status %d", subURL, status)
    } else {
      err = json.Unmarshal(subB, &sub)
    }
  } else {
    err = fmt.Errorf("failed to marshal subscription for %s", resourceAddress)
  }
  return
}
  1. Replace <node_name> with the FQDN of the node that is generating the PTP events. For example, compute-1.example.com.
Example PTP events consumer getCurrentState function in Go
//Get PTP event state for the resource
func getCurrentState(resource string) {
  //Create publisher
  url := &types.URI{URL: url.URL{Scheme: "http",
    Host: "ptp-event-publisher-service-<node_name>.openshift-ptp.svc.cluster.local:9043", 
    Path: fmt.SPrintf("/api/ocloudNotifications/v2/%s/CurrentState",resource}}
  rc := restclient.New()
  status, event := rc.Get(url)
  if status != http.StatusOK {
    log.Errorf("CurrentState:error %d from url %s, %s", status, url.String(), event)
  } else {
    log.Debugf("Got CurrentState: %s ", event)
  }
}
  1. Replace <node_name> with the FQDN of the node that is generating the PTP events. For example, compute-1.example.com.

Reference event consumer deployment and service CRs using PTP events REST API v2

Use the following example PTP event consumer custom resources (CRs) as a reference when deploying your PTP events consumer application for use with the PTP events REST API v2.

Reference cloud event consumer namespace
apiVersion: v1
kind: Namespace
metadata:
  name: cloud-events
  labels:
    security.openshift.io/scc.podSecurityLabelSync: "false"
    pod-security.kubernetes.io/audit: "privileged"
    pod-security.kubernetes.io/enforce: "privileged"
    pod-security.kubernetes.io/warn: "privileged"
    name: cloud-events
    openshift.io/cluster-monitoring: "true"
  annotations:
    workload.openshift.io/allowed: management
Reference cloud event consumer deployment
apiVersion: apps/v1
kind: Deployment
metadata:
  name: cloud-consumer-deployment
  namespace: cloud-events
  labels:
    app: consumer
spec:
  replicas: 1
  selector:
    matchLabels:
      app: consumer
  template:
    metadata:
      annotations:
        target.workload.openshift.io/management: '{"effect": "PreferredDuringScheduling"}'
      labels:
        app: consumer
    spec:
      nodeSelector:
        node-role.kubernetes.io/worker: ""
      serviceAccountName: consumer-sa
      containers:
        - name: cloud-event-consumer
          image: cloud-event-consumer
          imagePullPolicy: Always
          args:
            - "--local-api-addr=consumer-events-subscription-service.cloud-events.svc.cluster.local:9043"
            - "--api-path=/api/ocloudNotifications/v2/"
            - "--http-event-publishers=ptp-event-publisher-service-NODE_NAME.openshift-ptp.svc.cluster.local:9043"
          env:
            - name: NODE_NAME
              valueFrom:
                fieldRef:
                  fieldPath: spec.nodeName
            - name: CONSUMER_TYPE
              value: "PTP"
            - name: ENABLE_STATUS_CHECK
              value: "true"
      volumes:
        - name: pubsubstore
          emptyDir: {}
Reference cloud event consumer service account
apiVersion: v1
kind: ServiceAccount
metadata:
  name: consumer-sa
  namespace: cloud-events
Reference cloud event consumer service
apiVersion: v1
kind: Service
metadata:
  annotations:
    prometheus.io/scrape: "true"
  name: consumer-events-subscription-service
  namespace: cloud-events
  labels:
    app: consumer-service
spec:
  ports:
    - name: sub-port
      port: 9043
  selector:
    app: consumer
  sessionAffinity: None
  type: ClusterIP

Subscribing to PTP events with the REST API v2

Deploy your cloud-event-consumer application container and subscribe the cloud-event-consumer application to PTP events posted by the cloud-event-proxy container in the pod managed by the PTP Operator.

Subscribe consumer applications to PTP events by sending a POST request to http://ptp-event-publisher-service-NODE_NAME.openshift-ptp.svc.cluster.local:9043/api/ocloudNotifications/v2/subscriptions passing the appropriate subscription request payload.

Note

9043 is the default port for the cloud-event-proxy container deployed in the PTP event producer pod. You can configure a different port for your application as required.

Additional resources

Verifying that the PTP events REST API v2 consumer application is receiving events

Verify that the cloud-event-consumer container in the application pod is receiving Precision Time Protocol (PTP) events.

Prerequisites

  • You have installed the OpenShift CLI (oc).

  • You have logged in as a user with cluster-admin privileges.

  • You have installed and configured the PTP Operator.

  • You have deployed a cloud events application pod and PTP events consumer application.

Procedure

  1. Check the logs for the deployed events consumer application. For example, run the following command:

    $ oc -n cloud-events logs -f deployment/cloud-consumer-deployment
    Example output
    time = "2024-09-02T13:49:01Z"
level = info msg = "transport host path is set to  ptp-event-publisher-service-compute-1.openshift-ptp.svc.cluster.local:9043"
time = "2024-09-02T13:49:01Z"
level = info msg = "apiVersion=2.0, updated apiAddr=ptp-event-publisher-service-compute-1.openshift-ptp.svc.cluster.local:9043, apiPath=/api/ocloudNotifications/v2/"
time = "2024-09-02T13:49:01Z"
level = info msg = "Starting local API listening to :9043"
time = "2024-09-02T13:49:06Z"
level = info msg = "transport host path is set to  ptp-event-publisher-service-compute-1.openshift-ptp.svc.cluster.local:9043"
time = "2024-09-02T13:49:06Z"
level = info msg = "checking for rest service health"
time = "2024-09-02T13:49:06Z"
level = info msg = "health check http://ptp-event-publisher-service-compute-1.openshift-ptp.svc.cluster.local:9043/api/ocloudNotifications/v2/health"
time = "2024-09-02T13:49:07Z"
level = info msg = "rest service returned healthy status"
time = "2024-09-02T13:49:07Z"
level = info msg = "healthy publisher; subscribing to events"
time = "2024-09-02T13:49:07Z"
level = info msg = "received event {\"specversion\":\"1.0\",\"id\":\"ab423275-f65d-4760-97af-5b0b846605e4\",\"source\":\"/sync/ptp-status/clock-class\",\"type\":\"event.sync.ptp-status.ptp-clock-class-change\",\"time\":\"2024-09-02T13:49:07.226494483Z\",\"data\":{\"version\":\"1.0\",\"values\":[{\"ResourceAddress\":\"/cluster/node/compute-1.example.com/ptp-not-set\",\"data_type\":\"metric\",\"value_type\":\"decimal64.3\",\"value\":\"0\"}]}}"

  2. Optional. Test the REST API by using oc and port-forwarding port 9043 from the linuxptp-daemon deployment. For example, run the following command:

    $ oc port-forward -n openshift-ptp ds/linuxptp-daemon 9043:9043
    Example output
    Forwarding from 127.0.0.1:9043 -> 9043
Forwarding from [::1]:9043 -> 9043
Handling connection for 9043

    Open a new shell prompt and test the REST API v2 endpoints:

    $ curl -X GET http://localhost:9043/api/ocloudNotifications/v2/health
    Example output
    OK

Monitoring PTP fast event metrics

You can monitor PTP fast events metrics from cluster nodes where the linuxptp-daemon is running. You can also monitor PTP fast event metrics in the OpenShift Container Platform web console by using the preconfigured and self-updating Prometheus monitoring stack.

Prerequisites

  • Install the OpenShift Container Platform CLI oc.

  • Log in as a user with cluster-admin privileges.

  • Install and configure the PTP Operator on a node with PTP-capable hardware.

Procedure

  1. Start a debug pod for the node by running the following command:

    $ oc debug node/<node_name>

  2. Check for PTP metrics exposed by the linuxptp-daemon container. For example, run the following command:

    sh-4.4# curl http://localhost:9091/metrics
    Example output
    # HELP cne_api_events_published Metric to get number of events published by the rest api
# TYPE cne_api_events_published gauge
cne_api_events_published{address="/cluster/node/compute-1.example.com/sync/gnss-status/gnss-sync-status",status="success"} 1
cne_api_events_published{address="/cluster/node/compute-1.example.com/sync/ptp-status/lock-state",status="success"} 94
cne_api_events_published{address="/cluster/node/compute-1.example.com/sync/ptp-status/class-change",status="success"} 18
cne_api_events_published{address="/cluster/node/compute-1.example.com/sync/sync-status/os-clock-sync-state",status="success"} 27

  3. Optional. You can also find PTP events in the logs for the cloud-event-proxy container. For example, run the following command:

    $ oc logs -f linuxptp-daemon-cvgr6 -n openshift-ptp -c cloud-event-proxy

  4. To view the PTP event in the OpenShift Container Platform web console, copy the name of the PTP metric you want to query, for example, openshift_ptp_offset_ns.

  5. In the OpenShift Container Platform web console, click Observe → Metrics.

  6. Paste the PTP metric name into the Expression field, and click Run queries.

Additional resources

PTP fast event metrics reference

The following table describes the PTP fast events metrics that are available from cluster nodes where the linuxptp-daemon service is running.

Table 1. PTP fast event metrics
Metric Description Example

openshift_ptp_clock_class

Returns the PTP clock class for the interface. Possible values for PTP clock class are 6 (LOCKED), 7 (PRC UNLOCKED IN-SPEC), 52 (PRC UNLOCKED OUT-OF-SPEC), 187 (PRC UNLOCKED OUT-OF-SPEC), 135 (T-BC HOLDOVER IN-SPEC), 165 (T-BC HOLDOVER OUT-OF-SPEC), 248 (DEFAULT), or 255 (SLAVE ONLY CLOCK).

{node="compute-1.example.com",process="ptp4l"} 6

openshift_ptp_clock_state

Returns the current PTP clock state for the interface. Possible values for PTP clock state are FREERUN, LOCKED, or HOLDOVER.

{iface="CLOCK_REALTIME", node="compute-1.example.com", process="phc2sys"} 1

openshift_ptp_delay_ns

Returns the delay in nanoseconds between the primary clock sending the timing packet and the secondary clock receiving the timing packet.

{from="master", iface="ens2fx", node="compute-1.example.com", process="ts2phc"} 0

openshift_ptp_ha_profile_status

Returns the current status of the highly available system clock when there are multiple time sources on different NICs. Possible values are 0 (INACTIVE) and 1 (ACTIVE).

{node="node1",process="phc2sys",profile="profile1"} 1 {node="node1",process="phc2sys",profile="profile2"} 0

openshift_ptp_frequency_adjustment_ns

Returns the frequency adjustment in nanoseconds between 2 PTP clocks. For example, between the upstream clock and the NIC, between the system clock and the NIC, or between the PTP hardware clock (phc) and the NIC.

{from="phc", iface="CLOCK_REALTIME", node="compute-1.example.com", process="phc2sys"} -6768

openshift_ptp_interface_role

Returns the configured PTP clock role for the interface. Possible values are 0 (PASSIVE), 1 (SLAVE), 2 (MASTER), 3 (FAULTY), 4 (UNKNOWN), or 5 (LISTENING).

{iface="ens2f0", node="compute-1.example.com", process="ptp4l"} 2

openshift_ptp_max_offset_ns

Returns the maximum offset in nanoseconds between 2 clocks or interfaces. For example, between the upstream GNSS clock and the NIC (ts2phc), or between the PTP hardware clock (phc) and the system clock (phc2sys).

{from="master", iface="ens2fx", node="compute-1.example.com", process="ts2phc"} 1.038099569e+09

openshift_ptp_offset_ns

Returns the offset in nanoseconds between the DPLL clock or the GNSS clock source and the NIC hardware clock.

{from="phc", iface="CLOCK_REALTIME", node="compute-1.example.com", process="phc2sys"} -9

openshift_ptp_process_restart_count

Returns a count of the number of times the ptp4l and ts2phc processes were restarted.

{config="ptp4l.0.config", node="compute-1.example.com",process="phc2sys"} 1

openshift_ptp_process_status

Returns a status code that shows whether the PTP processes are running or not.

{config="ptp4l.0.config", node="compute-1.example.com",process="phc2sys"} 1

openshift_ptp_threshold

Returns values for HoldOverTimeout, MaxOffsetThreshold, and MinOffsetThreshold.

  • holdOverTimeout is the time value in seconds before the PTP clock event state changes to FREERUN when the PTP master clock is disconnected.

  • maxOffsetThreshold and minOffsetThreshold are offset values in nanoseconds that compare against the values for CLOCK_REALTIME (phc2sys) or master offset (ptp4l) values that you configure in the PtpConfig CR for the NIC.

{node="compute-1.example.com", profile="grandmaster", threshold="HoldOverTimeout"} 5

PTP fast event metrics only when T-GM is enabled

The following table describes the PTP fast event metrics that are available only when PTP grandmaster clock (T-GM) is enabled.

Table 2. PTP fast event metrics when T-GM is enabled
Metric Description Example

openshift_ptp_frequency_status

Returns the current status of the digital phase-locked loop (DPLL) frequency for the NIC. Possible values are -1 (UNKNOWN), 0 (INVALID), 1 (FREERUN), 2 (LOCKED), 3 (LOCKED_HO_ACQ), or 4 (HOLDOVER).

{from="dpll",iface="ens2fx",node="compute-1.example.com",process="dpll"} 3

openshift_ptp_nmea_status

Returns the current status of the NMEA connection. NMEA is the protocol that is used for 1PPS NIC connections. Possible values are 0 (UNAVAILABLE) and 1 (AVAILABLE).

{iface="ens2fx",node="compute-1.example.com",process="ts2phc"} 1

openshift_ptp_phase_status

Returns the status of the DPLL phase for the NIC. Possible values are -1 (UNKNOWN), 0 (INVALID), 1 (FREERUN), 2 (LOCKED), 3 (LOCKED_HO_ACQ), or 4 (HOLDOVER).

{from="dpll",iface="ens2fx",node="compute-1.example.com",process="dpll"} 3

openshift_ptp_pps_status

Returns the current status of the NIC 1PPS connection. You use the 1PPS connection to synchronize timing between connected NICs. Possible values are 0 (UNAVAILABLE) and 1 (AVAILABLE).

{from="dpll",iface="ens2fx",node="compute-1.example.com",process="dpll"} 1

openshift_ptp_gnss_status

Returns the current status of the global navigation satellite system (GNSS) connection. GNSS provides satellite-based positioning, navigation, and timing services globally. Possible values are 0 (NOFIX), 1 (DEAD RECKONING ONLY), 2 (2D-FIX), 3 (3D-FIX), 4 (GPS+DEAD RECKONING FIX), 5, (TIME ONLY FIX).

{from="gnss",iface="ens2fx",node="compute-1.example.com",process="gnss"} 3