Make leader election ID and election namespace optional.

[mneverov]

The main change is: introduced two new environment variables and added them to readme.
The lock ID and lock namespace are calculated now:

1. check new variables
2. check previously used variables POD_NAME and POD_NAMESPACE so the legacy behavior is the same
3. Use nodeutil.GetHostname and default namespace if none above. This allows to have the optional env. variables.

In retrospect it was a bad decision - should have hardcoded lock ID to smth like node-ipam-controller.k8s.io and use the default namespace as noone ever overrides these.

Fixes #39

[Copilot]

Pull Request Overview

This PR makes the leader election ID and namespace optional by introducing new environment variables and implementing fallback logic to maintain backward compatibility with existing deployments.

• Introduces IPAM_LEADER_ELECT_ID and IPAM_LEADER_ELECT_NAMESPACE environment variables for optional configuration
• Adds fallback logic that checks new variables first, then legacy POD_NAME/POD_NAMESPACE, and finally uses hostname/default namespace
• Refactors the leader election configuration structure and function signatures to consolidate parameters

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
pkg/leaderelection/leaderelection.go	Adds new config fields, implements fallback logic for lock ID/namespace, and refactors function signatures
main.go	Consolidates leader election config into a nested struct and updates function calls
README.md	Documents the new optional environment variables

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[aojea]

one just final comment and LGTM

[aojea]

/lgtm
/approve

Thanks for your hard work

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: aojea, mneverov

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• OWNERS [aojea,mneverov]

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[aojea]

@mneverov the bot complains because there is an invalid commit, so maybe you squash and merge now that is all reviewed?

[aojea]

/lgtm

I totally forget about this sorry

[aojea]

it is better if you ping me directly, github notifications are easy to miss