Configuration #

Specifying Operator Configuration #

The operator allows users to specify default configuration that will be shared by the Flink operator itself and the Flink deployments.

These configuration files are mounted externally via ConfigMaps. The Configuration files with default values are shipped in the Helm chart. It is recommended to review and adjust them if needed in the values.yaml file before deploying the Operator in production environments.

To append to the default configuration, simply define the flink-conf.yaml key in the defaultConfiguration section of the Helm values.yaml file:

  create: true
  # Set append to false to replace configuration files
  append: true
  flink-conf.yaml: |+
    # Flink Config Overrides
    kubernetes.operator.metrics.reporter.slf4j.factory.class: org.apache.flink.metrics.slf4j.Slf4jReporterFactory
    kubernetes.operator.metrics.reporter.slf4j.interval: 5 MINUTE

    kubernetes.operator.reconciler.reschedule.interval: 15 s 5 s

To learn more about metrics and logging configuration please refer to the dedicated docs page.

Dynamic Operator Configuration #

The Kubernetes operator supports dynamic config changes through the operator ConfigMaps. Dynamic operator configuration is enabled by default, and can be disabled by setting kubernetes.operator.dynamic.config.enabled to false. Time interval for checking dynamic config changes is specified by kubernetes.operator.dynamic.config.check.interval of which default value is 5 minutes.

Verify whether dynamic operator configuration updates is enabled via the deploy/flink-kubernetes-operator log has:

2022-05-28 13:08:29,222 o.a.f.k.o.c.FlinkConfigManager [INFO ] Enabled dynamic config updates, checking config changes every PT5M

To change config values dynamically the ConfigMap can be directly edited via kubectl patch or kubectl edit command. For example to change the reschedule interval you can override kubernetes.operator.reconciler.reschedule.interval.

Verify whether the config value of kubernetes.operator.reconciler.reschedule.interval is updated to 30 seconds via the deploy/flink-kubernetes-operator log has:

2022-05-28 13:08:30,115 o.a.f.k.o.c.FlinkConfigManager [INFO ] Updating default configuration to {kubernetes.operator.reconciler.reschedule.interval=PT30S}

Operator Configuration Reference #

Key Default Type Description
1000 Integer Max config cache size.
10 min Duration Expiration time for cached configs.
1 min Duration The timeout for deployments to become ready/stable before being rolled back if rollback is enabled.
false Boolean Whether to enable rolling back failed deployment upgrades.
5 min Duration Time interval for checking config changes.
true Boolean Whether to enable on-the-fly config changes through the operator configmap.
false Boolean Whether to ignore pending savepoint during job upgrade.
10 s Duration The timeout for the observer to wait the flink rest client to return.
10 s Duration The interval for observing status for in-progress operations such as deployment and savepoints.
10 s Duration Final delay before deployment is marked ready after port becomes accessible.
10 s Duration The interval before a savepoint trigger attempt is marked as unsuccessful.
1 min Duration The timeout for the reconciler to wait for flink to cancel job.
1 min Duration The timeout for the reconciler to wait for flink to shutdown cluster.
true Boolean Whether to enable recovery of missing/deleted jobmanager deployments.
5 Integer The maximum number of threads running the reconciliation loop. Use -1 for infinite.
1 min Duration The interval for the controller to reschedule the reconcile process.
86400000 ms Duration Maximum age for savepoint history entries to retain. Due to lazy clean-up, the most recent savepoint may live longer than the max age.
10 Integer Maximum number of savepoint history entries to retain.
"/opt/flink/artifacts" String The base dir to put the session job artifacts.
(none) Map Custom HTTP header for HttpArtifactFetcher. The header will be applied when getting the session job artifacts. Expected format: headerKey1:headerValue1,headerKey2:headerValue2.

Job Specific Configuration Reference #

Job specific configuration can be configured under spec.flinkConfiguration and it will override flink configurations defined in flink-conf.yaml.

  • For application clusters, spec.flinkConfiguration will be located in FlinkDeployment CustomResource.
  • For session clusters, configuring spec.flinkConfiguration in parent FlinkDeployment will be applied to all session jobs within the session cluster.
    • You can configure some additional job specific supplemental configuration through spec.flinkConfiguration in FlinkSessionJob CustomResource. Those session job level configurations will override the parent session cluster’s Flink configuration. Please note only the following configurations are considered to be valid configurations.
      • kubernetes.operator.user.artifacts.http.header