Change default az to empty when create cinder volume

[animationzl]

What this PR does / why we need it:

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #72

Special notes for your reviewer:

Release note:

[k8s-ci-robot]

Thanks for your pull request. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

📝 Please follow instructions at https://git.k8s.io/community/CLA.md#the-contributor-license-agreement to sign the CLA.

It may take a couple minutes for the CLA signature to be fully registered; after that, please reply here with a new comment and we'll verify. Thanks.

---

• If you've already signed a CLA, it's possible we don't have your GitHub username or you're using a different email address. Check your existing CLA data and verify that your email is set on your git commits.
• If you signed the CLA as a corporation, please sign in with your organization's credentials at https://identity.linuxfoundation.org/projects/cncf to be authorized.
• If you have done the above and are still having issues with the CLA being reported as unsigned, please email the CNCF helpdesk: helpdesk@rt.linuxfoundation.org

Details

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository. I understand the commands that are listed here.

[animationzl]

signed

[zetaab]

I am not fully sure should this PR be implemented like this. 90% of openstack users with kubernetes are using cinders as is for now. If this is changed like this, there is not backward compatibility and it means that it will break things.

Also what is behaviour is az is empty? Will it fail or will it just take first az from the cinder list? @animationzl so you have cinder az name something different than nova? Then imo we should not modify this behaviour, instead you can use parameters to specify and override the az.

[dims]

/assign @aglitke

[k8s-ci-robot]

@dims: GitHub didn't allow me to assign the following users: aglitke.

Note that only kubernetes members and repo collaborators can be assigned.

Details

In response to this:

/assign @aglitke

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[dims]

/approve

[dims]

@zetaab Note that this is the new external volume service, not the regular cinder one from the main k/k. So no one is using this yet.

[dims]

/ok-to-test

[zetaab]

@dims ok but still I would like to get answer how it behaves if az is empty.

[dims]

@animationzl please respond to @zetaab 's question

[animationzl]

@zetaab yes, the cloud provider I use has a different az name than nova, the default az in cinder create api is None, when creating volume without a specific az(such as cinder create 1), a random az of specific volume host which the volume is scheduled to will be chose as result.

[zetaab]

ok then I can approve that change :)

[zetaab]

/approve

@dims add LGTM if you think this is ok to merge

[dims]

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dims, zetaab

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Details

Needs approval from an approver in each of these files:

• pkg/volume/cinder/OWNERS [dims,zetaab]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment