Upgrade to latest version of kubebuilder

[dethi]

• Stop using operator-sdk, as we don't use any of the additional feature and it makes it harder to upgrade
• Switch to go/v4 plugin: this change a bit the layout of the project. go/v4 is the only supported version and ensure that we will support newer version of Go and Kubernetes.
• Enabling the pprof endpoint is now directly part of the manager
• Namespace cannot be specified anymore. This makes the controller watch for the CRD in all namespaces. Future changes are needed to support managing multiple clusters from the same controller.
• Upgrade gohbase to the latest version available.

[pidren]

Namespace cannot be specified anymore. This makes the controller watch for the CRD in all namespaces.

Why are we even upgrading then?

[dethi]

Because it never made sense to hardcode the namespace in the operator anyway. Now the operator can be deployed in any namespace, like hbase-system if wanted, and is able to react to the CRD being used in another namespace, like hbase. All the ressources managed by the operator itself will be deployed in the same namespace as the CRD. That's what every operator is doing.

The only limitation right now of this operator is that it takes the zookeeper config as an argument instead of being part of the CRD, which means it can only manage one CRD/HBase cluster at a time. I intend to change that in a follow-up PR.

[dethi]

As for why upgrading:

• kubebuilder and controller-runtime generally only support a specific version of Go, in that case the previous version was not supporting Go >1.19. This meant that there are dependencies I couldn't even upgrade.
• They also support a set of Kubernetes version. If you want to be able to use newer feature of Kubernetes, you have to upgrade to newer version.
• etc

ABU

[pidren]

Let me clarify my point:

This makes the controller watch for the CRD in all namespaces.

This will not work on the larger production clusters. It's inherently a worse setup than what we have today.

[dethi]

Having the operator watch for its own CRD in one namespace or all namespaces ultimately shouldn't change anything, since it is still watching only its own CRD type and thus if there is only one instance of that CRD, the usage should be the same.

[dethi]

That being said, I added back the flag (the option has moved in the manager to the cache). This way it can be enabled/disabled like before. And multi instance of the CRD setup is not something that works today anyway, but something I may address in a follow-up PR.