Comment 3 for bug 1934154

Reviewed: https://review.opendev.org/c/starlingx/ansible-playbooks/+/798918
Committed: https://opendev.org/starlingx/ansible-playbooks/commit/cfe9421fc4001e9a8c54d5e47ce2cd97d3e4f428
Submitter: "Zuul (22348)"
Branch: master

commit cfe9421fc4001e9a8c54d5e47ce2cd97d3e4f428
Author: Yuxing Jiang <email address hidden>
Date: Wed Jun 30 09:58:24 2021 -0500

    Restore ssh data from the backup data

    This commit restores the ssh configurations and keys in /etc/ssh from
    the backup tarball. After this commit, host keys from the backed-up
    host will be restored to the newly installed host, so the other hosts
    can ssh to the new host as a known host with the existing keys stored
    in there ~/.ssh/known_hosts.

    This commit is based on:
    https://review.opendev.org/c/starlingx/ansible-playbooks/+/798909.
    With that commit, the ansible ssh connection will not be rejected due
    to the remote host key change.

    Test steps:

    Test for backup/restore:
    1. Build a fresh ISO with these two commits.
    2. Install a DC system with two system controllers and one aiosx
    subcloud controller.
    3. SSH this subcloud as sysadmin and su with its oam address, mgmt
    address and subcloud name to add its key to ~/.ssh/known_hosts. Repeat
    this step(except the subcloud name) from an external host for the same
    purpose.
    4. Backup the subcloud data and reinstall the subcloud afterwards.
    5. Restore the subcloud successfully, and unlock the subcloud
    afterwards.
    6. After the restore, ssh to the subcloud with its oam address, mgmt
    address and subcloud name will be accepted from the system controllers
    or the external host.

    Test for upgrade orchestration:
    1. Install a N load in DC system
    2. Ssh to a subcloud with its name from a central cloud as the
    sysadmin user.
    3. Build a N+1 ISO with these two commits
    4. Upgrade the system controllers as well as the subcloud
    5. After the upgrading the subcloud, the sysadmin and still ssh to the
    subcloud with its name without deleting the previous host key in
    /home/sysadmin/.ssh/known_hosts

    Depends-On:
    https: //review.opendev.org/c/starlingx/ansible-playbooks/+/798909
    Closes-Bug: 1934154
    Signed-off-by: Yuxing Jiang <email address hidden>
    Change-Id: I3dd2820645fadae0903bc8784a0841ac5cca8a30