Launch Virtual Machines Quickly with spinup

For a long time now, I’ve been using Vagrant to quickly launch a VM or two when I need to. Recently, I’ve been less and less satisfied with Vagrant. It’s usually slow and needs editing the Vagrantfile if I want to change the machine specs. The slowness might be partially due to using VirtualBox by default. There is a vagrant-libvirt plugin that lets you use libvirt/KVM but the plugin seems to be a hit-and-miss affair and I’ve not been able to make it work all the time.

There is always the option of using virsh and other libvirt utilities, of course, to launch VMs, but that is not as simple as I’d like. I finally decided to write some sort of wrapper script for libvirt and here it is: spinup –a simple utility to launch VMs as fast as possible.

You need to clone the repository, run prepare.sh and you’re set to use spinup. I’ll also assume that you’ve made a symlink to spinup.py as spinup in an appropriate place, and installed the dependencies, so that the utility is always easily available to you. There’s of course the option of installing dependencies in a virtualenv and running ./spinup.py from there. You will obviously need libvirtd available, too.

The easiest way to launch a VM is by running this:

$ spinup

This will create an Ubuntu based VM with 1GiB of RAM and one CPU core, downloading the Ubuntu cloud image the first time you run it. To land inside the VM, simply run:

$ spinup ssh

The created VM is tied to the directory you create it in (although no files are created in that directory). So you need to be in that directory in order to have access to the VM.

In order to destroy the VM, simply run:

$ spinup destroy

You can create a VM with different specs like this:

$ spinup coreos 4G 2cpus

This will create a CoreOS based VM with 4GiB of RAM and two CPU cores.

It’s also possible to launch multiple VMs at the same time:

$ spinup :foo ubuntu 2G -- :bar coreos 4G 2cpus

Here we have created two VMs, naming them foo and bar respectively. In order to ssh into bar simply run:

$ spinup ssh bar

Running spinup destroy will destroy both VMs.

One area in which spinup is sorely lacking at the moment is networking. The created VMs are connected to libvirt’s default network, but there are no other options. I’m hoping to fix this in the near future. (Update: configuring network is now available, although you might need to create the appropriate libvirt networks first.)

spinup is in its very early stages of development, released in the “release early, release often” spirit. If you have any questions, you can send me an email at mostafa(at)sepent.com or create an issue or send a pull request over at github.