[CPDEV-98822] Remove default resolvConf from kubelet-config ConfigMap

[ilia1243]

Description

Default value of resolvConf is uploaded to kubelet-config ConfigMap by kubeadm.
This causes problems in migration of operating systems, because resolvConf is taken from the ConfigMap,
while it should be different on different OS.

Fixes #586

Solution

If resolvConf is not redefined in the inventory, remove it from kubelet-config ConfigMap

• during kubeadm init of the first control plane.
• during kubemarine reconfigure
• in services.kubelet.configuration PaaS check when generating the CM for comparison.

How to apply

Run kubemarine migrate_kubemarine --force-apply kubelet_resolvConf

Test Cases

TestCase 1

Migrate from Ubuntu 22.04 to RHEL9.

Steps:

1. Install cluster on Ubuntu 22.04.
2. Add node on RHEL9.

Results:

Before	After
Node is not joined. journalctl for kubelet contains error "open /run/systemd/resolve/resolv.conf: no such file or directory"	Node is joined

TestCase 2

Migrate from Centos 7 to Ubuntu 22.04

Steps:

1. Install cluster on Centos 7.
2. Migrate on Ubuntu 22.04.
3. Run check_paas --tasks services.kubelet.configuration

Results:

Before	After
failed: "kubelet-config ConfigMap is not consistent with services.kubeadm_kubelet section"	Check is successful

TestCase 3

Migration of old clusters.

Steps:

1. Install cluster on Ubuntu 22.04 using older version of Kubemarine.

Next steps should be done using new version of Kubemarine.

2. Run check_paas --tasks services.kubelet.configuration

ER: failed: "kubelet-config ConfigMap is not consistent with services.kubeadm_kubelet section"

3. Run kubemarine migrate_kubemarine --force-apply kubelet_resolvConf
4. Run check_paas --tasks services.kubelet.configuration

ER: check is successful.

Checklist

• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• Integration CI passed
• Unit tests. If Yes list of new/changed tests with brief description
• There is no merge conflicts