Kubernetes cache-stack documentation update

[vanrar68]

Describe the bug

Keycloak "Configuring distributed cache" guide states that:

The following table shows transport stacks that are available without any further configuration than using the --cache-stack build option:
- tcp
- udp
- kubernetes

When running keycloak 17.0.0 built with --cache-stack=kubernetes on a Kubernetes cluster the following error is thrown:

2022-02-20 19:42:39,604 INFO  [org.infinispan.CONTAINER] (keycloak-cache-init) ISPN000128: Infinispan version: Infinispan 'Triskaidekaphobia' 13.0.5.Final
2022-02-20 19:42:39,711 INFO  [org.infinispan.CLUSTER] (keycloak-cache-init) ISPN000078: Starting JGroups channel `ISPN`
2022-02-20 19:42:40,401 ERROR [org.keycloak.quarkus.runtime.cli.ExecutionExceptionHandler] (main) ERROR: Failed to start server in (production) mode
2022-02-20 19:42:40,402 ERROR [org.keycloak.quarkus.runtime.cli.ExecutionExceptionHandler] (main) ERROR: Failed to start caches
2022-02-20 19:42:40,402 ERROR [org.keycloak.quarkus.runtime.cli.ExecutionExceptionHandler] (main) ERROR: org.infinispan.manager.EmbeddedCacheManagerStartupException: org.infinispan.commons.CacheConfigurationException: ISPN000085: Error while trying to create a channel using the specified configuration file: default-configs/default-jgroups-kubernetes.xml
2022-02-20 19:42:40,402 ERROR [org.keycloak.quarkus.runtime.cli.ExecutionExceptionHandler] (main) ERROR: org.infinispan.commons.CacheConfigurationException: ISPN000085: Error while trying to create a channel using the specified configuration file: default-configs/default-jgroups-kubernetes.xml
2022-02-20 19:42:40,403 ERROR [org.keycloak.quarkus.runtime.cli.ExecutionExceptionHandler] (main) ERROR: ISPN000085: Error while trying to create a channel using the specified configuration file: default-configs/default-jgroups-kubernetes.xml
2022-02-20 19:42:40,404 ERROR [org.keycloak.quarkus.runtime.cli.ExecutionExceptionHandler] (main) ERROR: dns_query can not be null or empty
2022-02-20 19:42:40,404 ERROR [org.keycloak.quarkus.runtime.cli.ExecutionExceptionHandler] (main) For more details run the same command passing the '--verbose' option. Also you can use '--help' to see the details about the usage of the particular command.

Version

17.0.0

Expected behavior

No response

Actual behavior

No response

How to Reproduce?

No response

Anything else?

No response

[JingJCV]

As the log suggested, you need to pass jgroups.dns.query value to keycloak. This is a required property.
https://infinispan.org/docs/dev/titles/embedding/embedding.html#kubernetes
I did it like this #10359 but not sure the better way.

[vanrar68]

Ok thanks. I guess the statement "without any further configuration" in the Keycloak guide isn't really accurate. Maybe someone from the team can move this issue over to keycloak-documentation

[vanrar68]

I added the jgroups.dns.query property with the value pointing to the keycloak-headless service FQDN and it worked.
I opened issue 1416 on the keycloak-documentation repository

[vanrar68]

Turns out the cluster/cache guide is part of the keycloak project and not the keycloak-documentation project. Will push a PR that fixes the doc