Paramiko for hermetic SSH connections

[mattyclarkson]

Currently the SSHDriver calls out to the ssh binary to perform SSH connections.

paramiko is a pure Python library for providing SSH connections.

We could use paramiko in the SSHDriver to remove the need for a host installed ssh. Another option would be a ParamikoDriver that performs the same as SSHDriver but with paramiko.

labgrid-client ssh naturally forwards on arguments to the host ssh so would likely stay that way.

Would be of interest to project to investigate usage of paramiko?

[Emantor]

We evaluated this in 2016 when labgrid was initially written. Paramiko AFAICS still has no support for the control socket infrastructure where connections are multiplexed over one initial connection. Background was that we wanted labgrid to reuse an existing open connection to the target if possible.

This was important to us then, but might not be as important now, unfortunately I don't know how much this feature is used currently.

[jluebbe]

I use this all the time, as it significantly improves performances, especially when using SSH's ProxyJump mechanism.

Also, we use SSH as a backend for rsync and for port forwarding, which wouldn't be easy if we were using Paramiko in the labgrid Python process.

[mattyclarkson]

Would a ParamikoDriver be something of interest? It wouldn't be as efficient as the SSHDriver but would work in environments without ssh installed (also assuming that you do not need labgrid-client {ssh,rsync} functionality).

[jluebbe]

Without ssh, large parts of labgrid cannot be used, so I'd see ssh as a dependency. As we wouldn't use a ParamikoDriver in our setup, it would needs someone to commit to maintain it.