feat: add common labels to etcd services

[subnix]

Any vtop object contains common labels (component, cluster) except etcd services, but the labels may be necessary for other k8s components (e.g. ServiceMonitor).

Before the patch:

$ kubectl get svc -l 'etcd.planetscale.com/lockserver' -o 'custom-columns=name:.metadata.name,labels:.metadata.labels'
name                        labels
test-etcd-ea36c7ce-client   map[etcd.planetscale.com/lockserver:test-etcd-ea36c7ce]
test-etcd-ea36c7ce-peer     map[etcd.planetscale.com/lockserver:test-etcd-ea36c7ce]

After the patch:

$ kubectl get svc -l 'etcd.planetscale.com/lockserver' -o 'custom-columns=name:.metadata.name,labels:.metadata.labels'
name                        labels
test-etcd-ea36c7ce-client   map[etcd.planetscale.com/lockserver:test-etcd-ea36c7ce planetscale.com/cluster:test planetscale.com/component:etcd]
test-etcd-ea36c7ce-peer     map[etcd.planetscale.com/lockserver:test-etcd-ea36c7ce planetscale.com/cluster:test planetscale.com/component:etcd]

[mattlord]

Thank you, @subnix ! This seems like a safe and reasonable addition.

We don't have any tests here though... in lieu of that, could you please add something in the description that clearly demonstrates what the labels looked like (an example is fine) before and when they now look like in the PR branch? That's my only request -- doesn't have to be much.

[subnix]

@mattlord I've built a docker image, so you can reproduce it.

$ kubectl apply -f ./test/endtoend/operator/operator.yaml
$ kubectl apply -f ./test/endtoend/operator/101_initial_cluster.yaml
$ sleep 1m
$ kubectl get svc -l 'etcd.planetscale.com/lockserver' -o 'custom-columns=name:.metadata.name,labels:.metadata.labels'
name                           labels
example-etcd-faf13de3-client   map[etcd.planetscale.com/lockserver:example-etcd-faf13de3]
example-etcd-faf13de3-peer     map[etcd.planetscale.com/lockserver:example-etcd-faf13de3]
$ sed -E -i '' 's|planetscale/vitess-operator:.*|ghcr.io/subnix/vitess-operator:etcd-service-labels|g' ./test/endtoend/operator/operator.yaml
$ kubectl apply -f ./test/endtoend/operator/operator.yaml
$ sleep 1m
$ kubectl get svc -l 'etcd.planetscale.com/lockserver' -o 'custom-columns=name:.metadata.name,labels:.metadata.labels'
name                           labels
example-etcd-faf13de3-client   map[etcd.planetscale.com/lockserver:example-etcd-faf13de3 planetscale.com/cluster:example planetscale.com/component:etcd]
example-etcd-faf13de3-peer     map[etcd.planetscale.com/lockserver:example-etcd-faf13de3 planetscale.com/cluster:example planetscale.com/component:etcd]

[mattlord]

Thank you for the contribution, @subnix !

[frouioui]

Thank you for this nice contribution @subnix 🥳