[occm] Multi region openstack cluster

[sergelogvinov]

What this PR does / why we need it:

Openstack CCM multi region support, if it has one Identity provider.

Which issue this PR fixes(if applicable): fixes #1924

Special notes for reviewers:

CCM config changes:

[Global]
auth-url=https://auth.openstack.example.com/v3/
region=REGION1
# new param 'regions' can be specified multiple times
regions=REGION1
regions=REGION2
regions=REGION3

Optionally can be set in cloud.conf

clouds:
  kubernetes:
    auth:
      auth_url: https://auth.openstack.example.com/v3
    region_name: "REGION1"
    regions:
      - REGION1
      - REGION2
      - REGION3

During the initialization process, OCCM checks for the existence of providerID. If providerID does not exist, it defaults to using node.name, as it did previously. Additionally, if the node has the label topology.kubernetes.io/region, OCCM will prioritize using this region as the first one to check. This approach ensures that in the event of a region outage, OCCM can continue to function.

In addition, we can assist CCM in locating the node by providing kubelet parameters:

• --provider-id=openstack:///$InstanceID - InstanceID exists in metadata
• --provider-id=openstack://$REGION/$InstanceID - if you can define the region (by default meta server does not have this information)
• --node-labels=topology.kubernetes.io/region=$REGION set preferred REGION in label, OCCM will then prioritize searching for the node in this specified region

Release note:

NONE

[k8s-ci-robot]

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[k8s-ci-robot]

Hi @sergelogvinov. Thanks for your PR.

I'm waiting for a kubernetes 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.

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[sergelogvinov]

@mdbooth can you take a look on this PR. Probably I need to add more configuration checks.

Thanks.

[MatthieuFin]

Hi @sergelogvinov I propose an implementation of multi cloud support for cinder-csi-plugin, which offer multiple openstack clusters support, not only multiple regions, I haven't take look of occm implementation yet, but is it possible to adapt it to support multiple cloud definitions instead of only multiple regions ?

[sergelogvinov]

Hi @sergelogvinov I propose an implementation of multi cloud support for cinder-csi-plugin, which offer multiple openstack clusters support, not only multiple regions, I haven't take look of occm implementation yet, but is it possible to adapt it to support multiple cloud definitions instead of only multiple regions ?

Thank you for this PR, it is very interesting. Can we have a call/chat in slack #provider-openstack (Serge Logvinov)?

[jichenjc]

/ok-to-test

[jichenjc]

/ok-to-test

[k8s-ci-robot]

PR needs rebase.

Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes-sigs/prow](https://github.com/kubernetes-sigs/prow/issues/new?title=Prow%20issue:) repository.