[crmsh-4.5] Dev: bootstrap: more robust implementation for ssh_merge (bsc#1230530)

[nicholasyang2022]

• Do not use legacy write_remote_file, which does not work well with _guess_user_for_ssh.
• Implement deduplication when merging known_hosts

[codecov]

Codecov Report

Attention: Patch coverage is 86.66667% with 2 lines in your changes missing coverage. Please review.

Project coverage is 65.78%. Comparing base (80d011e) to head (85ace09).
Report is 12 commits behind head on crmsh-4.5.

Files with missing lines	Patch %	Lines
crmsh/bootstrap.py	86.66%	2 Missing ⚠️

Additional details and impacted files

Flag	Coverage Δ
integration	51.83% <86.66%> (+0.01%)	⬆️
unit	47.47% <20.00%> (+<0.01%)	⬆️

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Files with missing lines	Coverage Δ
crmsh/utils.py	68.75% <ø> (-0.03%)	⬇️
crmsh/bootstrap.py	82.12% <86.66%> (+0.41%)	⬆️

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[nicholasyang2022]

How to reproduce

We need to emulate a cluster with key-based ssh authentication set up in advance, and ensure there are at least 2 existing nodes in the cluster, so that ssh_merge has some host keys to merge.

1. on node1: crm cluster init -N node2 -y
2. on node3:
   1. ssh-keygen
   2. ssh-copy-id node2
   3. crm cluster join ssh_merge -c node2 -y

[liangxin1300]

How to reproduce

We need to emulate a cluster with key-based ssh authentication set up in advance, and ensure there are at least 2 existing nodes in the cluster, so that ssh_merge has some host keys to merge.

1. on node1: crm cluster init -N node2 -y

2. on node3:

   1. ssh-keygen
   2. ssh-copy-id node2
   3. crm cluster init ssh_merge -c node2 -y

I can reproduce following above steps.
btw, the third step should be crm cluster join ssh_merge -c node2 -y

[liangxin1300]

As the user still using stages to setup cluster, I suggest we backport #1384 to crmsh-4.5 and crmsh-4.4