Description of problem:

As $subject, the issue is similar to this upstream ticket:

https://community.theforeman.org/t/remote-execution-fails-to-use-ssh-key/28395

Foreman issue:

https://projects.theforeman.org/issues/34867

As mentioned in the ticket, a workaround is to explicitly set password to nil:

~~~
echo 'Setting[:remote_execution_ssh_password] = nil' | foreman-rake console
~~~

and restart the services.

Version-Release number of selected component (if applicable):

How reproducible:

Easy

Steps to Reproduce:
1. set Default SSH password
2. set Default SSH key passphrase
3. remove Default SSH passord
4. run a REX job

Actual results:

the job hangs and sshd debug shows the last line:

Postponed publickey for xxx from xxxxx port 39250 ssh2 [preauth]

Expected results:

the job should finish successfully.

Additional info: