[libvirt-users] Making remote access to qemu://session easier?

[Cole Robinson]

On 05/02/2016 11:57 AM, Lars Kellogg-Stedman wrote:
> This is frustrating:
> 
>   $ export LIBVIRT_DEFAULT_URI=qemu+ssh://remotehost/session
>   $ virsh list
>   error: failed to connect to the hypervisor
>   error: no valid connection
>   error: Operation not supported: Connecting to session instance without socket path is not supported by the ssh connection driver
> 
> Has there been any thought given to making this easier?  It seems that
> having a simple helper script on the remote host that could make the
> same "use $XDG_RUNTIME_DIR or use $HOME/.confg" decision as libvirtd
> would be able determine the socket path automatically.
> 
> Would that be a reasonable solution?
> 
> I see that right now, even support for qemu://remotehost/system
> requires that "virsh" knows that path to the remote socket, so having
> a remote helper that can read the libvirt configuration might simplify
> things in general.
> 
> That is, I am envisioning that for .../session connections, virsh
> would do something like:
> 
>     ssh remotehost libvirt-socket-helper --user
> 
> And for .../system connections, virsh would do something like:
> 
>     ssh remotehost libvirt-socket-helper --system
> 
> Rather than:
> 
>    ssh remotehost sh -c 'if nc -q 2>&1 | grep \"requires an argument\"
>    >/dev/null 2>&1; then ARG=-q0;else ARG=;fi;nc $ARG -U /var/run/libvirt/libvirt-sock'
> 
> 
> And in either of the above cases, "libvirt-socket-helper" would parse
> the environment and the libvirtd configuration as necessary and
> ultimately act like "nc -U /path/to/some/socket".

Yes it's been thought of before, see this bug which isn't heavy on details but
it would likely look something like your proposal:
https://bugzilla.redhat.com/show_bug.cgi?id=1241313

Just no one has gotten around to implementing it yet

- Cole