Support custom AWS endpoint configuration.

[jihunseol]

What would you like to be added:
Is there any plan to support custom AWS endpoint configuration for AWS VPC CNI plugin?
To use AWS VPC CNI plugin for custom AWS endpoint environment(e.g. testing environment), it would be great to support custom AWS endpoint configuration like below.

• Using map configuration like aws-load-balancer-controller (format: ec2=URL1,monitoring=URL2)
• Using environment variable like aws-ebs-csi-driver (format: AWS_EC2_ENDPOINT, AWS_CLOUDWATCH_ENDPOINT)

Why is this needed:
In order to use AWS VPC CNI plugin for testing environment(AWS API compatible), it is necessary to support custom AWS endpoint configuration.

[jdn5126]

@jihunseol yeah, this was brought up before in #2101 . We have been trying to push for no more non-functional environment variables, but an environment variable may be the only reasonable approach here.

If you would like to revive this old PR and follow the approach from ebs-csi-driver (https://github.com/kubernetes-sigs/aws-ebs-csi-driver/blob/master/pkg/cloud/cloud.go#L252), I am ok with that. Just need to do some testing

[jihunseol]

@jdn5126 I noticed that the previously closed pull request has already addressed the issue. It would be helpful to reopen the old PR instead of opening a new one to avoid duplicate work. Thanks for considering the issue.

[jdn5126]

That's fine with me too, but I don't think the individual who opened that initial PR is working on this or following it, so it probably needs someone new to drive it

[jihunseol]

Thank you for letting me know. If there is no issue, I would be happy to take one the responsibility of driving this pull request forward.

[jdn5126]

Awesome, thank you so much for the help!

[jihunseol]

I have submitted pull request #2326 to address the issue. As per the approach used in ebs-csi-driver, I have skipped unit testing for this code.
Should I update the README.md file to introduce this new environment variable? If so, I will update the README.md file accordingly.

[github-actions]

⚠️COMMENT VISIBILITY WARNING⚠️

Comments on closed issues are hard for our team to see.
If you need more assistance, please open a new issue that references this one.
If you wish to keep having a conversation with other community members under this issue feel free to do so.