After adding a new key with

    ssh-keygen -C '' -N '' -f ssh_host_ed25519_key -t ed25519

And making propellor aware of this with the property

    Ssh.hostKeys "myhost" [ (SshEd25519, "ssh-ed25519 ...") ]

and running 

    cat ssh_host_ed25519_key | propellor --set 'SshPrivKey SshEd25519 ""' 'myhost'
    propellor --spin myhost

I got the following error in my auth.log:

    error: Could not load host key: /etc/ssh/ssh_host_ed25519_key

after adding a newline at the end of /etc/ssh/ssh_host_ed25519_key, everything works well...

Is that a bug in propellor?



