Monitor SSH status for libvirt workers

When the libvirt master starts, it creates a ssh connection to the worker machine for each defined worker. If for any reason that ssh connection drops, then there will be build failures. The master doesn't handle at all this and a master restart is needed.

Ways to reproduce:
1. Look into the running processes on hz-bbm1 and there should be several entries like

buildma+ 3576703 3576701  0 14:45 ?        00:00:00 ssh -p 65001 -l buildbot -T -e none -- 100.64.100.20 sh -c 'which virt-ssh-helper 1>/dev/null 2>&1; if test $? = 0; then     virt-ssh-helper 'qemu:///system'; else    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; fi'

2. Libvirt restart on the worker machine (hz-bbw5)
3. Go back to 1 and there should be no active ssh connection
4. Master restart

Ideas for monitoring:
faust would it be possible to monotor if there is at least one ssh connection similar to the one from above?