fix: don't error if pod has no containerStatuses (#4471)

[ianroberts]

Summary

kill-host-pods.py iterates over all pods in all namespaces looking for pods that are running on the current node. But if any pods in the iteration do not have containerStatuses in their pod status structure (e.g. if they're Pending waiting for a valid node to schedule to) then this currently causes the script to crash with a KeyError. This PR changes the code to treat a missing containerStatuses the same as an empty one, so the pod is correctly skipped rather than the whole script crashing.

Closes #4471

Changes

• changed pod["status"]["containerStatuses"] (which raises an error if containerStatuses is missing) to pod["status"].get("containerStatuses") (which simply returns None).

Testing

Tested locally with a copy of the script, I believe the change is trivial enough not to require automated tests beyond this.

Checklist

• Read the contributions page.
• Submitted the CLA form, if you are a first time contributor.
• The introduced changes are covered by unit and/or integration tests.

Notes

[neoaggelos]

LGTM, thanks a lot for the catch @ianroberts !

[neoaggelos]

Would you also mind signing the CLA? And I believe we should also backport this change to older branches as well

[ianroberts]

Would you also mind signing the CLA? And I believe we should also backport this change to older branches as well

I did just sign the CLA, though the email address I've used is a secondary email on my launchpad account (iroberts-usfd) rather than the preferred one.

[neoaggelos]

The CLA check fails with:

Checking the following users on Launchpad:
- ian@$DOMAIN ✕ (has no Launchpad account)

Can you amend the commit and use the email that you signed the CLA with?

[ianroberts]

The CLA check fails with:

Checking the following users on Launchpad:
- ian@$DOMAIN ✕ (has no Launchpad account)

Can you amend the commit and use the email that you signed the CLA with?

That's what I mean - the email I signed the CLA with is ian@$DOMAIN, and that email address is associated with my launchpad account, but it was a secondary rather than primary email address.

I've just edited my launchpad profile to swap the primary and secondary addresses, can you run the CLA checker again now?

[ianroberts]

Sorry, my bad, I had added the address to my Ubuntu one account but not directly to my Launchpad account, it should be there now. But I'm not showing as a member of https://launchpad.net/~contributor-agreement-canonical, maybe I need to fill in the CLA again now the right emails are all linked?

[neoaggelos]

Yes, can you please sign the CLA with the email address used in the commit? Thank you!

[ianroberts]

I already had, twice... just filled in the form again, let's see if it takes this time.

Edit: I see it's at least found the matching LP account for my email now.