[Bug] HeadGroupSpec.Replicas is unused

[kevin85421]

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KubeRay Component

ray-operator

What happened + What you expected to happen

This bug is found by #605. When I updated the value of headGroupSpec.replicas from 1 to 2. It breaks this rule. The number of workers is determined by worker.Replicas (code), but HeadGroupSpec.Replicas is unused in KubeRay.

Possible solutions:
(1) Remove the HeadGroupSpec.Replicas field.
(2) Create head pods based on HeadGroupSpec.Replicas.

Reproduction script

• Updated the value of headGroupSpec.replicas in your YAML file from 1 to 2.

Anything else

No response

Are you willing to submit a PR?

• Yes I am willing to submit a PR!

[kevin85421]

cc @DmitriGekhtman

[DmitriGekhtman]

Thank you for tracking this!
See also #362, which made the field optional.

I think we should remove the field in the next RayCluster API version.

[DmitriGekhtman]

So the solution is bullet (2) in your proposal.
I believe I've already removed the field in all example docs and documented the field as deprecated in the raycluster_types.go.

[DmitriGekhtman]

Oh, actually I think I left it in the examples for compatibility with KubeRay 0.2.0.
But now that we've released KubeRay 0.3.0, we can remove the field from all examples!
@kevin85421 would you mind doing the honors of hunting down and deleting all instances of HeadGroupSpec.replicas in example yamls?

[kevin85421]

Thank @DmitriGekhtman for the reply! Why do not we remove HeadGroupSpec.Replicas from raycluster_types.go? I tried to remove the field from raycluster_types.go, and it can still keep backward compatibility.

# Step 1: Remove  `HeadGroupSpec.Replicas` from `raycluster_types.go`
# Step 2: Update CRD / generated API
make sync

# Step 3: zz_generated_deepcopy.go
make generate 

# Step4: Build docker image
make docker-image

# Step 5: Install new KubeRay operator (controller:latest) and new CRD
# Step 6: Install RayCluster with `HeadGroupSpec.Replicas`

# Work well.

[Jeffwan]

We have an issue to track it and we need to do some clean up on the api.

[kevin85421]

Related issue: #368