Enable schema validation for postgresql CRD

[sdudoladov]

A few misconfigurations may be catched by k8s-native CRD validation early

[gane5hvarma]

Hi @sdudoladov I would like to work on this issue.by the way im new to kubernetes and i would like to work on it.

[Jan-M]

@gane5hvarma PRs are always welcome ;)

[yujunz]

Absolutely needed. Any progress so far?

For example, I'd like the change being rejected if it has no effect. Otherwise the actual status will deviate from the spec.

postgres-operator-8886ccf-nqdvf:postgres-operator time="2019-07-09T07:11:40Z" level=warning msg="postgresql version change(\"10\" -> \"9.6\") has no effect" cluster-name=postgres-operator/hl-dev pkg=cluster worker=2

[Jan-M]

We are working on syntax/schema validation now. See referenced PR.

We do not yet intend to include checking "semantic" meaning and valid transitions. Which is also not supported I think by CRD schema.

And ultimately the 9.6 to 10 transition could be implemented by someone in the Docker image.

[yujunz]

How does the operator determine some modifications has no effect at the moment?

[Jan-M]

I think this particular change is hard coded to inform users that this is not how major version upgrade works. (Spilo does it via Clone/Restore in Custom Bootstrap).

[yujunz]

And ultimately the 9.6 to 10 transition could be implemented by someone in the Docker image.
(Spilo does it via Clone/Restore in Custom Bootstrap).

A bit confused on current status. Is it supported (even with some adhoc operations) or not?

[Jan-M]

The Postgres operator itself does not really support/do this. Migrating to a new major version in place is not supported right now and we are also not working on it right now.

What is supported is upgrading the major version when doing a clone or restore from AWS S3 e.g.

This is implemented in Spilo during the custom bootstrap. So we bootstrap from S3 backup. Upgrade single node and only then continue bootstraping replica nodes.

Using clone/restore is a convenient and safe flow that is still easier than dump restore.

[yujunz]

What is supported is upgrading the major version when doing a clone or restore from AWS S3

This is good enough since major version upgrade is not that often.