tillrohrmann commented on a change in pull request #14254:
URL: https://github.com/apache/flink/pull/14254#discussion_r532455932
##########
File path: docs/deployment/ha/kubernetes_ha.md
##########
@@ -23,77 +23,50 @@ specific language governing permissions and limitations
under the License.
-->
-## Kubernetes Cluster High Availability
-Kubernetes high availability service could support both [standalone Flink on
Kubernetes]({% link deployment/resource-providers/standalone/kubernetes.md %})
and [native Kubernetes integration]({% link
deployment/resource-providers/native_kubernetes.md %}).
+Flink's Kubernetes HA services use [Kubernetes](https://kubernetes.io/) for
high availability services.
-When running Flink JobManager as a Kubernetes deployment, the replica count
should be configured to 1 or greater.
-* The value `1` means that a new JobManager will be launched to take over
leadership if the current one terminates exceptionally.
-* The value `N` (greater than 1) means that multiple JobManagers will be
launched simultaneously while one is active and others are standby. Starting
more than one JobManager will make the recovery faster.
+* Toc
+{:toc}
-### Configuration
-{% highlight yaml %}
-kubernetes.cluster-id: <ClusterId>
-high-availability:
org.apache.flink.kubernetes.highavailability.KubernetesHaServicesFactory
-high-availability.storageDir: hdfs:///flink/recovery
-{% endhighlight %}
+Kubernetes high availability services can only be used when deploying to
Kubernetes.
+Consequently, they can be configured when using [standalone Flink on
Kubernetes]({% link deployment/resource-providers/standalone/kubernetes.md %})
or the [native Kubernetes integration]({% link
deployment/resource-providers/native_kubernetes.md %})
-#### Example: Highly Available Standalone Flink Cluster on Kubernetes
-Both session and job/application clusters support using the Kubernetes high
availability service. Users just need to add the following Flink config options
to [flink-configuration-configmap.yaml]({% link
deployment/resource-providers/standalone/kubernetes.md
%}#common-cluster-resource-definitions). All other yamls do not need to be
updated.
-
-<span class="label label-info">Note</span> The filesystem which corresponds to
the scheme of your configured HA storage directory must be available to the
runtime. Refer to [custom Flink image]({% link
deployment/resource-providers/standalone/docker.md %}#customize-flink-image)
and [enable plugins]({% link deployment/resource-providers/standalone/docker.md
%}#using-plugins) for more information.
-
-{% highlight yaml %}
-apiVersion: v1
-kind: ConfigMap
-metadata:
- name: flink-config
- labels:
- app: flink
-data:
- flink-conf.yaml: |+
- ...
- kubernetes.cluster-id: <ClusterId>
- high-availability:
org.apache.flink.kubernetes.highavailability.KubernetesHaServicesFactory
- high-availability.storageDir: hdfs:///flink/recovery
- restart-strategy: fixed-delay
- restart-strategy.fixed-delay.attempts: 10
- ...
-{% endhighlight %}
+## Configuration
-#### Example: Highly Available Native Kubernetes Cluster
-Using the following command to start a native Flink application cluster on
Kubernetes with high availability configured.
-{% highlight bash %}
-$ ./bin/flink run-application -p 8 -t kubernetes-application \
- -Dkubernetes.cluster-id=<ClusterId> \
- -Dtaskmanager.memory.process.size=4096m \
- -Dkubernetes.taskmanager.cpu=2 \
- -Dtaskmanager.numberOfTaskSlots=4 \
- -Dkubernetes.container.image=<CustomImageName> \
-
-Dhigh-availability=org.apache.flink.kubernetes.highavailability.KubernetesHaServicesFactory
\
- -Dhigh-availability.storageDir=s3://flink/flink-ha \
- -Drestart-strategy=fixed-delay -Drestart-strategy.fixed-delay.attempts=10 \
-
-Dcontainerized.master.env.ENABLE_BUILT_IN_PLUGINS=flink-s3-fs-hadoop-{{site.version}}.jar
\
-
-Dcontainerized.taskmanager.env.ENABLE_BUILT_IN_PLUGINS=flink-s3-fs-hadoop-{{site.version}}.jar
\
- local:///opt/flink/examples/streaming/StateMachineExample.jar
-{% endhighlight %}
+In order to start an HA-cluster you have to configure the following
configuration keys:
-### High Availability Data Clean Up
-Currently, when a Flink job reached the terminal state (`FAILED`, `CANCELED`,
`FINISHED`), all the HA data, including metadata in Kubernetes ConfigMap and HA
state on DFS, will be cleaned up.
+- **high-availability mode** (required):
+The [`high-availability`]({% link deployment/config.md %}#high-availability-1)
option has to be set to `KubernetesHaServicesFactory`.
-So the following command will only shut down the Flink session cluster and
leave all the HA related ConfigMaps, state untouched.
-{% highlight bash %}
-$ echo 'stop' | ./bin/kubernetes-session.sh
-Dkubernetes.cluster-id=<ClusterId> -Dexecution.attached=true
-{% endhighlight %}
+ <pre>high-availability:
org.apache.flink.kubernetes.highavailability.KubernetesHaServicesFactory</pre>
+
+- **Storage directory** (required):
+JobManager metadata is persisted in the file system
[`high-availability.storageDir`]({% link deployment/config.md
%}#high-availability-storagedir) and only a pointer to this state is stored in
ZooKeeper.
Review comment:
Good catch :-)
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