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, define the flink-conf.yaml key in the defaultConfiguration section of the Helm values.yaml file:
defaultConfiguration:
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.reconcile.interval: 15 s
kubernetes.operator.observer.progress-check.interval: 5 s
To learn more about metrics and logging configuration please refer to the dedicated docs page.
Flink Version and Namespace specific defaults #
The operator also supports default configuration overrides for selected Flink versions and namespaces. This can be important if some behaviour changed across Flink versions or we want to treat certain namespaces differently (such as reconcile it more or less frequently etc).
# Flink Version specific defaults
kubernetes.operator.default-configuration.flink-version.v1_17.k1: v1
kubernetes.operator.default-configuration.flink-version.v1_17.k2: v2
kubernetes.operator.default-configuration.flink-version.v1_17.k3: v3
# Namespace specific defaults
kubernetes.operator.default-configuration.namespace.ns1.k1: v1
kubernetes.operator.default-configuration.namespace.ns1.k2: v2
kubernetes.operator.default-configuration.namespace.ns2.k1: v1
Flink version specific defaults will have a higher precedence so namespace defaults would be overridden by the same key.
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.reconcile.interval.
Verify whether the config value of kubernetes.operator.reconcile.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.reconcile.interval=PT30S}
Leader Election and High Availability #
The operator supports high availability through leader election and standby operator instances. To enable leader election you need to add the following two mandatory operator configuration parameters.
kubernetes.operator.leader-election.enabled: true
kubernetes.operator.leader-election.lease-name: flink-operator-lease
Lease name must be unique in the current lease namespace. For other more advanced config parameters please refer to the configuration reference.
Once you enabled leader election you can increase the replicas for the operator Deployment using the Helm chart to enable high availability.
If replicas value is greater than 1, you can define topologySpreadConstraints
via operatorPod.topologySpreadConstraints.
Environment variables #
The operator exposes several environment variables which can be used for custom plugins.
| Name | Description | FieldRef |
|---|---|---|
| HOST_IP | The host which the pod is deployed on | status.hostIP |
| POD_IP | Pod IP | status.podIP |
| POD_NAME | Pod Name | metadata.name |
Operator Configuration Reference #
System Configuration #
General operator system configuration. Cannot be overridden on a per-resource basis.
| Key | Default | Type | Description |
|---|---|---|---|
kubernetes.operator.dynamic.namespaces.enabled |
false | Boolean | Enables dynamic change of watched/monitored namespaces. |
kubernetes.operator.exception.field.max.length |
2048 | Integer | Maximum length of each exception field including stack trace to be included in CR status error field. |
kubernetes.operator.exception.stacktrace.enabled |
false | Boolean | Enable exception stacktrace to be included in CR status error field. |
kubernetes.operator.exception.stacktrace.max.length |
2048 | Integer | Maximum length of stacktrace to be included in CR status error field. |
kubernetes.operator.exception.throwable.list.max.count |
2 | Integer | Maximum number of throwable to be included in CR status error field. |
kubernetes.operator.flink.client.cancel.timeout |
1 min | Duration | The timeout for the reconciler to wait for flink to cancel job. |
kubernetes.operator.flink.client.timeout |
10 s | Duration | The timeout for the observer to wait the flink rest client to return. |
kubernetes.operator.leader-election.enabled |
false | Boolean | Enable leader election for the operator to allow running standby instances. |
kubernetes.operator.leader-election.lease-duration |
15 s | Duration | Leader election lease duration. |
kubernetes.operator.leader-election.lease-name |
(none) | String | Leader election lease name, must be unique for leases in the same namespace. |
kubernetes.operator.leader-election.renew-deadline |
10 s | Duration | Leader election renew deadline. |
kubernetes.operator.leader-election.retry-period |
2 s | Duration | Leader election retry period. |
kubernetes.operator.reconcile.interval |
1 min | Duration | The interval for the controller to reschedule the reconcile process. |
kubernetes.operator.reconcile.parallelism |
200 | Integer | The maximum number of threads running the reconciliation loop. Use -1 for infinite. |
kubernetes.operator.resource.cleanup.timeout |
1 min | Duration | The timeout for the resource clean up to wait for flink to shutdown cluster. |
kubernetes.operator.retry.initial.interval |
5 s | Duration | Initial interval of automatic reconcile retries on recoverable errors. |
kubernetes.operator.retry.interval.multiplier |
2.0 | Double | Interval multiplier of automatic reconcile retries on recoverable errors. |
kubernetes.operator.retry.max.attempts |
10 | Integer | Max attempts of automatic reconcile retries on recoverable errors. |
kubernetes.operator.user.artifacts.base.dir |
"/opt/flink/artifacts" | String | The base dir to put the session job artifacts. |
kubernetes.operator.watched.namespaces |
"JOSDK_ALL_NAMESPACES" | String | Comma separated list of namespaces the operator monitors for custom resources. |
Resource/User Configuration #
These options can be configured on both an operator and a per-resource level. When set under spec.flinkConfiguration for the Flink resources it will override the default value provided in the operator default configuration (flink-conf.yaml).
| Key | Default | Type | Description |
|---|---|---|---|
kubernetes.operator.cluster.health-check.checkpoint-progress.enabled |
false | Boolean | Whether to enable checkpoint progress health check for clusters. |
kubernetes.operator.cluster.health-check.checkpoint-progress.window |
5 min | Duration | If no checkpoints are completed within the defined time window, the job is considered unhealthy. This must be bigger than checkpointing interval. |
kubernetes.operator.cluster.health-check.enabled |
false | Boolean | Whether to enable health check for clusters. |
kubernetes.operator.cluster.health-check.restarts.threshold |
64 | Integer | The threshold which is checked against job restart count within a configured window. If the restart count is reaching the threshold then full cluster restart is initiated. |
kubernetes.operator.cluster.health-check.restarts.window |
2 min | Duration | The duration of the time window where job restart count measured. |
kubernetes.operator.deployment.readiness.timeout |
5 min | Duration | The timeout for deployments to become ready/stable before being rolled back if rollback is enabled. |
kubernetes.operator.deployment.rollback.enabled |
false | Boolean | Whether to enable rolling back failed deployment upgrades. |
kubernetes.operator.exception.label.mapper |
Map | Key-Value pair where key is the REGEX to filter through the exception messages and value is the string to be included in CR status error label field if the REGEX matches. Expected format: headerKey1:headerValue1,headerKey2:headerValue2. | |
kubernetes.operator.jm-deployment-recovery.enabled |
true | Boolean | Whether to enable recovery of missing/deleted jobmanager deployments. |
kubernetes.operator.jm-deployment.shutdown-ttl |
86400000 ms | Duration | Time after which jobmanager pods of terminal application deployments are shut down. |
kubernetes.operator.jm-deployment.startup.probe.enabled |
true | Boolean | Enable job manager startup probe to allow detecting when the jobmanager could not submit the job. |
kubernetes.operator.job.restart.failed |
false | Boolean | Whether to restart failed jobs. |
kubernetes.operator.job.savepoint-on-deletion |
false | Boolean | Indicate whether a savepoint must be taken when deleting a FlinkDeployment or FlinkSessionJob. |
kubernetes.operator.job.upgrade.ignore-pending-savepoint |
false | Boolean | Whether to ignore pending savepoint during job upgrade. |
kubernetes.operator.job.upgrade.inplace-scaling.enabled |
true | Boolean | Whether to enable inplace scaling for Flink 1.18+ using the resource requirements API. On failure or earlier Flink versions it falls back to regular full redeployment. |
kubernetes.operator.job.upgrade.last-state-fallback.enabled |
true | Boolean | Enables last-state fallback for savepoint upgrade mode. When the job is not running thus savepoint cannot be triggered but HA metadata is available for last state restore the operator can initiate the upgrade process when the flag is enabled. |
kubernetes.operator.job.upgrade.last-state.max.allowed.checkpoint.age |
(none) | Duration | Max allowed checkpoint age for initiating last-state upgrades on running jobs. If a checkpoint is not available within the desired age (and nothing in progress) a savepoint will be triggered. |
kubernetes.operator.periodic.savepoint.interval |
0 ms | Duration | Interval at which periodic savepoints will be triggered. The triggering schedule is not guaranteed, savepoints will be triggered as part of the regular reconcile loop. |
kubernetes.operator.pod-template.merge-arrays-by-name |
false | Boolean | Configure the array merge behaviour during pod merging. Arrays can be either merged by position or name matching. |
kubernetes.operator.savepoint.cleanup.enabled |
true | Boolean | Whether to enable clean up of savepoint history. |
kubernetes.operator.savepoint.format.type |
CANONICAL | Enum |
Type of the binary format in which a savepoint should be taken. Possible values:
|
kubernetes.operator.savepoint.history.max.age |
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. |
kubernetes.operator.savepoint.history.max.count |
10 | Integer | Maximum number of savepoint history entries to retain. |
kubernetes.operator.savepoint.trigger.grace-period |
1 min | Duration | The interval before a savepoint trigger attempt is marked as unsuccessful. |
kubernetes.operator.user.artifacts.http.header |
(none) | Map | Custom HTTP header for HttpArtifactFetcher. The header will be applied when getting the session job artifacts. Expected format: headerKey1:headerValue1,headerKey2:headerValue2. |
Autoscaler Configuration #
Like other resource options these can be configured on both an operator and a per-resource level. When set under spec.flinkConfiguration for the Flink resources it will override the default value provided in the operator default configuration (flink-conf.yaml).
| Key | Default | Type | Description |
|---|---|---|---|
kubernetes.operator.job.autoscaler.backlog-processing.lag-threshold |
5 min | Duration | Lag threshold which will prevent unnecessary scalings while removing the pending messages responsible for the lag. |
kubernetes.operator.job.autoscaler.catch-up.duration |
5 min | Duration | The target duration for fully processing any backlog after a scaling operation. Set to 0 to disable backlog based scaling. |
kubernetes.operator.job.autoscaler.enabled |
false | Boolean | Enable job autoscaler module. |
kubernetes.operator.job.autoscaler.history.max.age |
86400000 ms | Duration | Maximum age for past scaling decisions to retain. |
kubernetes.operator.job.autoscaler.history.max.count |
3 | Integer | Maximum number of past scaling decisions to retain per vertex. |
kubernetes.operator.job.autoscaler.metrics.busy-time.aggregator |
MAX | Enum |
Metric aggregator to use for busyTime metrics. This affects how true processing/output rate will be computed. Using max allows us to handle jobs with data skew more robustly, while avg may provide better stability when we know that the load distribution is even. Possible values:
|
kubernetes.operator.job.autoscaler.metrics.window |
10 min | Duration | Scaling metrics aggregation window size. |
kubernetes.operator.job.autoscaler.restart.time |
3 min | Duration | Expected restart time to be used until the operator can determine it reliably from history. |
kubernetes.operator.job.autoscaler.scale-down.max-factor |
0.6 | Double | Max scale down factor. 1 means no limit on scale down, 0.6 means job can only be scaled down with 60% of the original parallelism. |
kubernetes.operator.job.autoscaler.scale-up.grace-period |
1 h | Duration | Duration in which no scale down of a vertex is allowed after it has been scaled up. |
kubernetes.operator.job.autoscaler.scale-up.max-factor |
100000.0 | Double | Max scale up factor. 2.0 means job can only be scaled up with 200% of the current parallelism. |
kubernetes.operator.job.autoscaler.scaling.effectiveness.detection.enabled |
false | Boolean | Whether to enable detection of ineffective scaling operations and allowing the autoscaler to block further scale ups. |
kubernetes.operator.job.autoscaler.scaling.effectiveness.threshold |
0.1 | Double | Processing rate increase threshold for detecting ineffective scaling threshold. 0.1 means if we do not accomplish at least 10% of the desired capacity increase with scaling, the action is marked ineffective. |
kubernetes.operator.job.autoscaler.scaling.enabled |
true | Boolean | Enable vertex scaling execution by the autoscaler. If disabled, the autoscaler will only collect metrics and evaluate the suggested parallelism for each vertex but will not upgrade the jobs. |
kubernetes.operator.job.autoscaler.stabilization.interval |
5 min | Duration | Stabilization period in which no new scaling will be executed |
kubernetes.operator.job.autoscaler.target.utilization |
0.7 | Double | Target vertex utilization |
kubernetes.operator.job.autoscaler.target.utilization.boundary |
0.4 | Double | Target vertex utilization boundary. Scaling won't be performed if the current processing rate is within [target_rate / (target_utilization - boundary), (target_rate / (target_utilization + boundary)] |
kubernetes.operator.job.autoscaler.vertex.exclude.ids |
List<String> | A (semicolon-separated) list of vertex ids in hexstring for which to disable scaling. Caution: For non-sink vertices this will still scale their downstream operators until https://issues.apache.org/jira/browse/FLINK-31215 is implemented. | |
kubernetes.operator.job.autoscaler.vertex.max-parallelism |
200 | Integer | The maximum parallelism the autoscaler can use. Note that this limit will be ignored if it is higher than the max parallelism configured in the Flink config or directly on each operator. |
kubernetes.operator.job.autoscaler.vertex.min-parallelism |
1 | Integer | The minimum parallelism the autoscaler can use. |
System Metrics Configuration #
Operator system metrics configuration. Cannot be overridden on a per-resource basis.
| Key | Default | Type | Description |
|---|---|---|---|
kubernetes.operator.josdk.metrics.enabled |
true | Boolean | Enable forwarding of Java Operator SDK metrics to the Flink metric registry. |
kubernetes.operator.jvm.metrics.enabled |
true | Boolean | Enable Kubernetes Operator JVM metrics. |
kubernetes.operator.kubernetes.client.metrics.enabled |
true | Boolean | Enable KubernetesClient metrics for measuring the HTTP traffic to the Kubernetes API Server. |
kubernetes.operator.kubernetes.client.metrics.http.response.code.groups.enabled |
false | Boolean | Enable KubernetesClient metrics for measuring the HTTP traffic to the Kubernetes API Server by response code group, e.g. 1xx, 2xx. |
kubernetes.operator.metrics.histogram.sample.size |
1000 | Integer | Defines the number of measured samples when calculating statistics. |
kubernetes.operator.metrics.scope.k8soperator.resource |
"<host>.k8soperator.<namespace>.<name>.resource.<resourcens>.<resourcename>.<resourcetype>" | String | Defines the scope format string that is applied to all metrics scoped to the kubernetes operator resource. |
kubernetes.operator.metrics.scope.k8soperator.resourcens |
"<host>.k8soperator.<namespace>.<name>.namespace.<resourcens>.<resourcetype>" | String | Defines the scope format string that is applied to all metrics scoped to the kubernetes operator resource namespace. |
kubernetes.operator.metrics.scope.k8soperator.system |
"<host>.k8soperator.<namespace>.<name>.system" | String | Defines the scope format string that is applied to all metrics scoped to the kubernetes operator. |
kubernetes.operator.resource.lifecycle.metrics.enabled |
true | Boolean | Enable resource lifecycle state metrics. This enables both state and transition counts/histograms. |
kubernetes.operator.resource.lifecycle.namespace.histograms.enabled |
true | Boolean | In addition to the system level histograms, enable per namespace tracking of state and transition times. |
kubernetes.operator.resource.metrics.enabled |
true | Boolean | Enables metrics for FlinkDeployment and FlinkSessionJob custom resources. |
Advanced System Configuration #
Advanced operator system configuration. Cannot be overridden on a per-resource basis.
| Key | Default | Type | Description |
|---|---|---|---|
kubernetes.operator.config.cache.size |
1000 | Integer | Max config cache size. |
kubernetes.operator.config.cache.timeout |
10 min | Duration | Expiration time for cached configs. |
kubernetes.operator.dynamic.config.check.interval |
5 min | Duration | Time interval for checking config changes. |
kubernetes.operator.dynamic.config.enabled |
true | Boolean | Whether to enable on-the-fly config changes through the operator configmap. |
kubernetes.operator.health.canary.resource.timeout |
1 min | Duration | Allowed max time between spec update and reconciliation for canary resources. |
kubernetes.operator.health.probe.enabled |
true | Boolean | Enables health probe for the kubernetes operator. |
kubernetes.operator.health.probe.port |
8085 | Integer | The port the health probe will use to expose the status. |
kubernetes.operator.label.selector |
(none) | String | Label selector of the custom resources to be watched. Please see https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/#label-selectors for the format supported. |
kubernetes.operator.observer.progress-check.interval |
10 s | Duration | The interval for observing status for in-progress operations such as deployment and savepoints. |
kubernetes.operator.observer.rest-ready.delay |
10 s | Duration | Final delay before deployment is marked ready after port becomes accessible. |
kubernetes.operator.resource.deletion.propagation |
Foreground | Enum |
JM/TM Deployment deletion propagation. Possible values:
|
kubernetes.operator.savepoint.history.max.age.threshold |
(none) | Duration | Maximum age threshold for savepoint history entries to retain. |
kubernetes.operator.savepoint.history.max.count.threshold |
(none) | Integer | Maximum number threshold of savepoint history entries to retain. |
kubernetes.operator.startup.stop-on-informer-error |
true | Boolean | Whether informer errors should stop operator startup. If false, the startup will ignore recoverable errors, caused for example by RBAC issues and will retry periodically. |
kubernetes.operator.termination.timeout |
10 s | Duration | Operator shutdown timeout before reconciliation threads are killed. |