I set up an SSH connection from my PostgreSQL docker container as the SSH server and the Barman remote host as the client. When I use backup_method=rsync I see an SSH connection established between the two. However, if I use backup_method=postgres then I do not see one.
I imagine there is some reason this is not supported. Unfortunately this appears not supported although the docs are ambiguous about this:
"This setup, in Barman's terminology, is known as streaming-only setup, as it does not require any SSH connection for backup and archiving operations. This is particularly suitable and extremely practical for Docker environments."
A stronger statement would be to say SSH for streaming-only is not supported at this time.
Why is this not supported? My assumption is that if I used SSH for the psql connection it would add a layer of security. I would not have tried to do so if it were clear in the documentation that this was not possible.