[Feature]: `nsscache` support

[synthe102]

Description

Supporting nsscache as an alternative to sssd would allow to cover a broader range of directory sources (notably http and S3).
So far the steps required to make this possible are to include nsscache and its supervirsord config in the slurm OCI images, and supply the nsscache config to the Pods either with an additional field in the NodeSet and LoginSet objects, or by mounting an extra secret.

I would gladly contribute this feature if it is approved.

Intended Behavior

LoginSets and NodeSets should support nsscache as an alternative to sssd. nsscache should be configurable with a Secret.

Additional Context

[vivian-hafener]

Good morning @synthe102,

This is related to an issue that the Slinky team is tracking internally as a longer-term work item. Once I have any updates on this matter, I will let you know.

Best,
Vivian Hafener

[synthe102]

Thanks @vivian-hafener for your reply. Do you have an approximate timeline (days/weeks/months?) regarding disclosure from the Slinky team ?
In the meantime I'll share some details of my implementation here.

[vivian-hafener]

Hi there @synthe102,

At this time I do not have a timeline for this, aside from that it will take some time. Supporting nsscache will require decoupling our container images from SSSD altogether, involving refactors of the container builders in slurm-operator along with the container images themselves, which will take a substantial amount of effort to do well. As I have updates on this development item, I will provide them.

Best,
Vivian Hafener

[SkylerMalinowski]

Hi @synthe102 ,

Do you have an approximate timeline (days/weeks/months?) regarding disclosure from the Slinky team ? In the meantime I'll share some details of my implementation here.

I think we are in a state where we can start to look at nsscache support for Slinky v1.3.0.

You propose nsscache being embedded in the containers and launched by supervisord. I don't love more daemon/processes in the container, but it may be the best way forward. Can you provide details of your implementation? It may easier to open a PR against containers repo with your implementation if that is preferable.