Add option to set different server group policy for etcd, node, and master server

[OlleLarsson]

What type of PR is this?

/kind feature

What this PR does / why we need it:
In the current release it is only possible to enable openstack server groups with a fixed policy of "anti-affinity" set for all server groups.
Hard anti-affinity might be fine when running on hyperscalar openstack clouds, but it quickly becomes a problem when running on smaller openstack clouds where the number of available compute nodes is not that great.
This pr enables enabling server groups and setting the desired policy for each individual server group.

Setting

master_server_group_policy = "anti-affinity"
node_server_group_policy   = "anti-affinity"
etcd_server_group_policy   = "anti-affinity"

equates to the same bahaviour as

use_server_groups = true

did.

Which issue(s) this PR fixes:

NA

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[Openstack] Replaces the global `use_server_groups` with the option to enable and set server group policy for each of the master, etcd, and node server groups respectively. ⚠️ <- ADD NOTE: action required

[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 log a ticket with the Linux Foundation Helpdesk: https://support.linuxfoundation.org/
• Should you encounter any issues with the Linux Foundation Helpdesk, send a message to the backup e-mail support address at: [email protected]

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.

[k8s-ci-robot]

Welcome @OlleLarsson!

It looks like this is your first PR to kubernetes-sigs/kubespray 🎉. Please refer to our pull request process documentation to help your PR have a smooth ride to approval.

You will be prompted by a bot to use commands during the review process. Do not be afraid to follow the prompts! It is okay to experiment. Here is the bot commands documentation.

You can also check if kubernetes-sigs/kubespray has its own contribution guidelines.

You may want to refer to our testing guide if you run into trouble with your tests not passing.

If you are having difficulty getting your pull request seen, please follow the recommended escalation practices. Also, for tips and tricks in the contribution process you may want to read the Kubernetes contributor cheat sheet. We want to make sure your contribution gets all the attention it needs!

Thank you, and welcome to Kubernetes. 😃

[k8s-ci-robot]

Hi @OlleLarsson. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

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.

[OlleLarsson]

@holmsten @bozzo PTAL 😄

[Xartos]

LGTM!

[cristiklein]

LGTM

[cristicalin]

/ok-to-test

[cristicalin]

Thank you @OlleLarsson for this fix!

/lgtm

[floryut]

Thanks for all the look on this PR 🙇
And good job @OlleLarsson

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: floryut, OlleLarsson, Xartos

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

The pull request process is described here

Needs approval from an approver in each of these files:

• contrib/terraform/OWNERS [floryut]

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