[Ray-operator] Feature flag login bash

[fscnick]

Why are these changes needed?

Provide a feature flag to enable the login bash command -l if needed. If feature flag is not enabled, it would not apply login bash. This provide the option for the end user to choose one. For example, the uv rely on PATH if enabling the login bash might overwrite PATH potentially.

Related issue number

Part of #3247

Checks

• I've made sure the tests are passing.
• Testing Strategy
  • Unit tests
  • Manual tests
  • This PR is not tested :(

[fscnick]

Without feature flag:

ray-head:

wait-gcs-ready:

ray-worker:

autoscaler:

rayjob result:

With feature flag:

enable feature flag:

raycluster with login bash:

[fscnick]

@kevin85421 PTAL

[kevin85421]

cc @MortalHappiness would you mind reviewing this PR? Thanks!

[MortalHappiness]

I remembered that in our offline discussion, we dicided to use environment variable instead of feature gates and config API, right?

[fscnick]

Hi @kevin85421 , just to make sure. Do we make it as environment variable or feature gate?

[kevin85421]

Please use an environment variable. Feature gates are meant to provide a way to gradually graduate a new feature from alpha to beta to GA. However, in this case, we are trying to deprecate an existing feature. That is, it is possible for us to remove the feature gate or env var. In this case, if we use feature gate, users need to update their YAML in the future.

[fscnick]

Change to the environment. @MortalHappiness PTAL

[MortalHappiness]

Also add a test for the case when the feature flag is not enabled, or add the checks to the TestBuildPod function.

[kevin85421]

Please check all /bin/bash occurrences in the codebase. For example, the RedisCleanupJob is not covered in the current PR.

[kevin85421]

Move to constant.go and rename it to ENABLE_LOGIN_SHELL.

https://arc.net/l/quote/oyzwyjmd

[kevin85421]

"This environment variable for the KubeRay operator determines whether to enable a login shell by passing the -l option to the container command /bin/bash. The -l flag was added by default before KubeRay v1.4.0, but it is no longer added by default starting with v1.4.0."

[kevin85421]

still reviewing

[kevin85421]

Can you add a utility function instead of calling GetEnableLoginBash multiple times across the codebase?

func GetContainerCommand() {
  if (enableLoginShell) {
    return []string{"/bin/bash", "-lc", "--"},
  }
  return []string{"/bin/bash", "-c", "--"},
}

[kevin85421]

I will open a follow up PR.