[kjobctl] Move common SLURM_envs to container env vars.

[mbobrovskyi]

What type of PR is this?

/kind cleanup

What this PR does / why we need it:

Move common SLURM_ envs to container env vars on kjobctl.

Which issue(s) this PR fixes:

Prepare #3269

Special notes for your reviewer:

We have many variables that are the same in each container, so there's no need to generate them in the init container. Instead of that we can set it as a container env vars on builder.

Does this PR introduce a user-facing change?

NONE

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: mbobrovskyi
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[mwielgus]

I'm afraid this will make the already big slurm job/pod definition significantly bigger. Is why is it needed?

[mbobrovskyi]

Is why is it needed?

We discussed on the previous weekly meeting to create init container on go. Before that trying to optimize init script.

[mbobrovskyi]

In another way we need to create a lot of flags for go slurm-init to send all of this values.

@mimowo @trasc WDYT?

[mbobrovskyi]

Another approach I also can see to get it from configmap.

[mwielgus]

Configmap sounds ok.

[trasc]

In another way we need to create a lot of flags for go slurm-init to send all of this values.

@mimowo @trasc WDYT?

I don't think that loading the env vars from a = separated file is such a big challenge in a go app (split by \n then by =). So, at least for now, we should not add an extra config map just for this.