libvirt buildserver is often in a broken state (needs --reset-server)
Whenever I don't use my buildserver for a while I get the following output, which can be fixed by running with --reset-server once.
DEBUG: both kvm and vbox are installed.
DEBUG: build vm provider lookup found 'libvirt'
DEBUG: vm uuid: 966b265a-a2e3-48cb-b994-f49e403d130e
==> vagrant: A new version of Vagrant is available: 2.1.5!
==> vagrant: To upgrade visit: https://www.vagrantup.com/downloads.html
Bringing machine 'default' up with 'libvirt' provider...
==> default: Starting domain.
==> default: Error when updating domain settings: Call to virDomainUndefineFlags failed: Requested operation is not valid: cannot delete inactive domain with 1 snapshots
==> default: Waiting for domain to get an IP address...
==> default: Waiting for SSH to become available...
==> default: Creating shared folders metadata...
DEBUG: vm uuid: 966b265a-a2e3-48cb-b994-f49e403d130e
INFO: suspending buildserver
==> default: Suspending domain...
INFO: builserver ok: reverting to clean snapshot
INFO: reverting vm 'builder_default' to snapshot 'fdroidclean'
Bringing machine 'default' up with 'libvirt' provider...
==> default: Resuming domain...
DEBUG: vm uuid: 966b265a-a2e3-48cb-b994-f49e403d130e
DEBUG: vagrant ssh-config
INFO: b'Current machine states:\n\ndefault running (libvirt)\n\nThe Libvirt domain is running. To stop this machine, you can run\n`vagrant halt`. To destroy the machine, you can run `vagrant destroy`.\n'
DEBUG: both kvm and vbox are installed.
DEBUG: build vm provider lookup found 'libvirt'
DEBUG: vm uuid: 966b265a-a2e3-48cb-b994-f49e403d130e
INFO: suspending buildserver
==> default: Suspending domain...
DEBUG: skip publishing full build logs: no output present
ERROR: Could not build app de.schildbach.oeffi: Could not obtain buildserverid from buldserver VM. (stored inside the buildserver VM at '/home/vagrant/buildserverid') Please reset your buildserver, the setup VM is broken.
INFO: Finished
INFO: 1 build failed
Not sure what's triggering this, maybe a system restart?