nomad operator debug - add client node filtering arguments

[davemay99]

Adds max-nodes, node-id=all, and node-class cmdline arguments to nomad operator debug

From the helpText:

  -max-nodes=<count>
    Cap the maximum number of client nodes included in the capture.  Defaults to 10, set to 0 for unlimited.

  -node-id=<node>,<node>
    Comma separated list of Nomad client node ids, to monitor for logs and include pprof
    profiles. Accepts id prefixes, and "all" to select all nodes (up to count = max-nodes).

  -node-class=<node-class>
    Filter client nodes based on node class.

[drewbailey]

I'm trying to see if there is any precedent for having unlimited be -1, so that you can actually specify 0

[davemay99]

If you don't specify -node-id then -max-nodes doesn't apply. In testing though I discovered that the max node count notice is incorrectly displayed in that case.

[drewbailey]

squinting at this block of code seems like it may be a nice candidate to pull out to a function, not a blocker though. I am curious why we defer removing the tmp directory? is it copied or moved somewhere down the road?

[davemay99]

The idea is to ensure that the temp directory is cleaned up before exit, regardless of any errors that may occur.

In local testing I have code that uses the NOMAD_TEST_SKIPCLEANUP environment variable to conditionally clean up (idea lifted from the E2E framework). If you think it's useful I can commit that as well.

[drewbailey]

changes look good to me, don't forget a changelog entry and also the website/ docs need to be updated with the new flags

[github-actions]

I'm going to lock this pull request because it has been closed for 120 days ⏳. This helps our maintainers find and focus on the active contributions.
If you have found a problem that seems related to this change, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.