Allow the namespace to be configurable

[matyix]

The namespace being watched by the operator (in main.go) is hardcoded. The namespace should be configurable at runtime when the operator is created.

[fanminshi]

@matyix the hardcoded namespace is just a default placeholder. Currently, we don't enforce
a particular way for user to set it up.

However, for etcd-operator and vault-operator, we do make the namespace configurable at runtime like what you suggested by reading the namespace from the pod's environment variable where the environment variable is set by the deployment manifest.

For instance:

namespace := os.Getenv("MY_POD_NAMESPACE")
...

and setup the env var MY_POD_NAMESPACE through the operator deployment yaml:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: <your-operator>
spec:
  replicas: 1
  template:
    metadata:
      labels:
        name: <your-operator>
    spec:
      containers:
      - name: <your-operator>
        image: <your-operator-image>
        env:
        - name: MY_POD_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace

[stoader]

@fanminshi I think it would make sense to have the namespace setting the way you suggested in the generated code. That would save time for developers as they don't have to figure out how to pass over the namespace and this implementation would work for most of the use cases. Those who have special requirements still can customise how to pass through the namespace.

[fanminshi]

@stoader thanks for the feedback. We will take this into consideration.

[matyix]

thx @fanminshi

[rongou]

What about watching all namespaces? Do we just pass in ""? And then the rbac role needs to be changed to a ClusterRole, right?

[fanminshi]

@rongou yeah, that sounds right to me. Have you tested it out yet?

[rongou]

Yes, seems to work. Probably should document this somewhere. :)

[eparis]

I'm not entirely sure #227 completely fixes this. It does at least allow the operator to work outside of the default namespace and shows what needs to change. #227 certainly feels like a better starting place for devs to me.