fix: create groups from legacy inventory even with limit flag set

[Adrian-St]

What type of PR is this?

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespaces from that line:
/kind bug

What this PR does / why we need it:

When using the legacy inventory with the kube-master and kube-node groups the boilerplate.yml playbook is supposed to add them to the kube_control_plane and kube_node group respectively.
The problem is that if you follow the docs and run the scale.yml playbook with the limit flag set to the new worker node (mentioned here) then it won't add the nodes from the kube-master group to the kube_control_plane group because it doesn't match any hosts.
Consequently the task "Stop if kube_control_plane group is empty" in roles/kubernetes/preinstall/tasks/0040-verify-settings.yml will fail.
The fix uses the add_host module instead which runs on all hosts and will always add the hosts from the legacy groups to the new groups, even if the limit flag is set.

Which issue(s) this PR fixes:

I haven't created an issue for this bug since the information in the bug template isn't relevant and I couldn't get vagrant to work easily, but let me know if it's needed and I can create one.
This bug should happen on any Kubespray version with the updated groups and the fix worked in our CI environment where we're using the legacy group names.

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

NONE

[linux-foundation-easycla]

• ❌ - login: @Adrian-St . The commit (186cb74, 6abde38) is not authorized under a signed CLA. Please click here to be authorized. For further assistance with EasyCLA, please submit a support request ticket.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: Adrian-St
Once this PR has been reviewed and has the lgtm label, please assign vannten for approval. For more information see the Kubernetes Code Review Process.

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

Needs approval from an approver in each of these files:

• OWNERS

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

[k8s-ci-robot]

Welcome @Adrian-St!

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 @Adrian-St. 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-sigs/prow repository.

[yankay]

/ok-to-test

[tico88612]

@Adrian-St Please make sure your CLA & CI check.