Add content for exploring the features of the v0.3.0 operator on GKE

[thelabdude]

Add a blog post for exploring the v0.3.0 release.

[janhoy]

This was a bit of a mouthful :) Skimmed it and it looks thorough, but did not have time to read it all just now. A few initial questions:

spec:
  acme:
    server: https://acme-v02.api.letsencrypt.org/directory
    email: *** REDACTED ***
    privateKeySecretRef:
      name: acme-letsencrypt-issuer-pk

Where is the acme-letsencrypt-issuer-pk defined? Guess the reference needs to point so some key somewhere?

2. If you want to terminate TLS through linkerd or ingress instead of on the solr node, is that supported by the operator? I know Solr itself may not be fully prepared for that case, since it will complain in logs that TLS is not active, and it is impossible to start solr with only a custom truststore without also enabling inbound tls. But aside from that, from an operator standpoint?

[thelabdude]

The cert-manager defines the acme-letsencrypt-issuer-pk secret, here's a good explanation from one of cert-manager's main contributors: cert-manager/cert-manager#1751 (comment)

Yes, you can do TLS termination at the Ingress, see: https://kubernetes.github.io/ingress-nginx/examples/tls-termination/ However, the Solr operator doesn't let you set the tls.secretName field in the YAML. So you'd have to work-around this by defining your own Ingress for Solr vs. using the one created by the operator. It's a limitation we should fix in 0.4.0 since it would require a change to the CRD definition. apache/solr-operator#268

[HoustonPutman]

This is great!

Made a few changes, that hopefully make it a bit easier for users. Just minor things though.

I do think it would be nice to have a short section explaining that the Provided Zookeeper section in the CRD is good for development use cases, but Production use cases should probably use explicit Zookeeper Connection Strings. Much like the comment you made on the slack channel.