Add TLS configuration for RPK connecting to the schema registry

[andrewstucki]

Currently installing a cluster with TLS enabled break RPKs interactions with the schema registry:

$ kubectl exec -it -n redpanda basic-0 -c redpanda -- rpk registry schema list
unable to GET "http://127.0.0.1:8081/subjects": Get "http://127.0.0.1:8081/subjects": EOF
command terminated with exit code 1

Where you can access it properly with curl:

$ kubectl exec -it -n redpanda basic-0 -c redpanda -- curl https://basic-0.basic.redpanda.svc.cluster.local:8081/subjects -sS --cacert /etc/tls/certs/default/ca.crt -sS -w '\n'
[]

This is because we're missing a schema_registry stanza from the rpk node configuration block:

rpk:
    kafka_api:
        brokers:
            - basic-0.basic.redpanda.svc.cluster.local.:9093
        tls:
            ca_file: /etc/tls/certs/default/ca.crt
    admin_api:
        addresses:
            - basic-0.basic.redpanda.svc.cluster.local.:9644
        tls:
            ca_file: /etc/tls/certs/default/ca.crt
    additional_start_flags:
        - --default-log-level=info
        - --memory=2048M
        - --reserve-memory=205M
        - --smp=1
    tune_aio_events: true

This adds the proper configuration so that RPK can interact with the schema registry.

[david-yu]

Thank you!

[andrewstucki]

Holding off on merging for a bit, realized that the schema_registry part of redpanda.yaml's rpk stanza isn't actually implemented and currently connection parameters for the schema registry can only be set via rpk profiles. I have a fix to bring it into the rpk stanza in repanda.yaml as well:

https://github.com/redpanda-data/redpanda/compare/allow-setting-schema-registry-via-rpk-node-config

But waiting to hear back on how we want to proceed, either just plugging the above for now or reworking the chart to use profiles, which sounds like it's likely the "preferred" way we tell folks to use RPK.

[andrewstucki]

Opened up redpanda-data/redpanda#24017 to implement being able to configure this in redpanda.yaml.

[david-yu]

I assume we need to wait for an rpk build (i.e. 24.3) to be out for this to merge? Or would it not matter? I assume docs with the rpk command would need to wait though for 24.3.

[andrewstucki]

@david-yu I'm going to go ahead and merge it -- it'll do nothing for the time being since older versions of rpk won't understand the stanza that was added and will just ignore it. I'll re-validate it once we cut the rpk/redpanda release.

[david-yu]

@andrewstucki I assume its possible to test with this RC release? https://github.com/redpanda-data/redpanda/releases/tag/untagged-5fe25a9a58fdcd612efd

[BenPope]

https://hub.docker.com/r/redpandadata/redpanda-unstable/tags?name=v24.3.1-rc4

[andrewstucki]

Thanks @BenPope!

@david-yu - works like a charm.

➜ kubectl exec -it -n redpanda basic-0 --container redpanda -- rpk registry schema list
SUBJECT        VERSION  ID    TYPE  ERROR
mytopic-value  1        1     AVRO