dehesselle / virtctl

start/stop libvirt-based VMs with systemd

virtctl - systemd service

About

virtctl is an instantiable systemd service for starting/stopping libvirt-based virtual machines (it interacts with virsh). It works out of the box with libvirt's default directory layout, i.e. systemctl start virtctl@DomainName starts /etc/libvirt/qemu/DomainName.xml, but can also be easily configured if you keep your files somewhere else.

If you're looking for an easy and customizable way to start and stop your VMs with systemd, you might want to take a look!

Setup

Basics

Copy the files from this repository to the following directories (alternative: AUR) and issue a systemctl daemon-reload afterwards:

root
┣━━━etc
┃   ┣━━━systemd
┃   ┃   ┗━━━system
┃   ┃       ┣━━━hypervisor.target
┃   ┃       ┣━━━virtctl@.service
┃   ┃       ┗━━━virtctl@.service.d
┃   ┃           ┗━━━file_layout.conf.example
┃   ┗━━━virtctl.d
┃       ┣━━━functions.sh
┃       ┣━━━instance_startpost.example
┃       ┗━━━instance_stoppost.example
┃
...

This is the full installation. For a minimal installation, only virtctl@.service is required (at the expense of some functionalities, of course).

In its default configuration, virtctl can already start and stop your VMs if

1. you adopted libvirt's directory layout and keep your domain XML in /etc/libvirt/qemu
2. you kept your naming consistent, i.e. for every domain the filename DomainName.xml matches exactly with the real name inside the XML, <name>DomainName</name>.

If your domain XML is somewhere else, take a look at file_layout.conf.example on how to override that setting with a drop-in file. The second requirement however must always be followed.

Advanced

virtctl provides its own mechanism to run "post start" and "post stop" actions for your VMs, similar to libvirt's own hooks. Just create a file DomainName_startpost and/or DomainName_stoppost, put your commands in there (these files get sourced by a bash shell, so no shebang!) and place it in /etc/virtctl.d or in the directory your domain XML is in.
If you have "post start" or "post stop" files in both locations, the one besides your domain XML takes precedence and the other one in /etc/virtctl.d will be ignored (they do not stack up / no include hierarchy).

port forwarding for NAT network

If you want to forward ports from your host to your guest, you can use the function forward_port in your "post start" action. Check the example in instance_startpost.example.
Port forwardings are automatically cleared when the VM shuts down.

start/stop on host boot/shutdown

virtctl provides a target named hypervisor.target. It depends on and is reached after multi-user.target. If you choose to systemctl enable virtctl@DomainName, it gets linked into hypervisor.target.wants.
The intention is to stay clear of multi-user.target so that you have a way to easily enable (or disable) all VMs at once, be it temporarily with systemctl isolate hypervisor or permanent/on boot with systemctl set-default hypervisor.

Limitations

• Multiple physical and/or virtual network adapters aren't supported.

start and stop VM

systemctl start  virtctl@DomainName
systemctl status virtctl@DomainName
systemctl stop   virtctl@DomainName

If you want systemd to automatically start/stop your VMs on boot/shutdown, enable them and set your default target.

systemctl enable virtctl@DomainName
systemctl set-default hypervisor

Famous last words

"It should work!" - and I'm hoping it does for you as well. Of course I cannot guarantee for anything, but I'm using this myself on a daily basis on multiple Arch Linux boxes.

Contributions

virtctl is available in AUR, provided by NihlisticPandemonium. Thank you very much 🙂!

License

MIT