If upstream userdb server is not reachable by ssh, charm doesn't complete ssh configs and install hook fails

[Drew Freiberger]

When deploying in an airgapped environment, udldap charm fails at:

unit-ud-ldap-server-0: 20:04:03 WARNING unit.ud-ldap-server/0.install File "/var/lib/juju/agents/unit-ud-ldap-server-0/charm/hooks/install.real", line 66, in setup_udldap
unit-ud-ldap-server-0: 20:04:03 WARNING unit.ud-ldap-server/0.install utils.update_ssh_known_hosts(["userdb.internal", userdb_ip])
unit-ud-ldap-server-0: 20:04:03 WARNING unit.ud-ldap-server/0.install File "/var/lib/juju/agents/unit-ud-ldap-server-0/charm/hooks/utils.py", line 302, in update_ssh_known_hosts
unit-ud-ldap-server-0: 20:04:03 WARNING unit.ud-ldap-server/0.install subprocess.check_call(["/usr/bin/ssh-keyscan", "-t", "rsa"] + hosts, stdout=fp)
unit-ud-ldap-server-0: 20:04:03 WARNING unit.ud-ldap-server/0.install File "/usr/lib/python3.8/subprocess.py", line 364, in check_call
unit-ud-ldap-server-0: 20:04:03 WARNING unit.ud-ldap-server/0.install raise CalledProcessError(retcode, cmd)
unit-ud-ldap-server-0: 20:04:03 WARNING unit.ud-ldap-server/0.install subprocess.CalledProcessError: Command '['/usr/bin/ssh-keyscan', '-t', 'rsa', 'userdb.internal', '<IP ADDRESS>']' returned non-zero exit status 1.

The rest of the install should complete so that local-only/manual rsync method can be used.

[Drew Freiberger (afreiberger)]

as a workaround, I added a 'try: except: pass' around line 302 in hooks/utils.py

[Eric Chen (eric-chen)]

This issue is pending for long time. If it is still valid, please open issue in
https://github.com/canonical/charm-userdir-ldap/