A recent feature has been introduced to allow launching images either located on the local disk or via a URL. This allows launching and starting new Multipass instances from Fedora cloud images or Ubuntu Core images for example.
High level overview of how this works:
$ multipass launch file:///path/to/local.img
$ multipass launch http://www.foo.com/bar.img
Here are a couple of real world examples:
A Fedora cloud image already exists on the local file system at /home/fred/Downloads/Fedora-Cloud-Base-28-1.1.x86_64.qcow2. To launch this:
$ multipass launch file:///home/fred/Downloads/Fedora-Cloud-Base-28-1.1.x86_64.qcow2
This will create a Fedora Multipass instance using all of the defaults and the auto-generated name. The standard options used for creating an instance apply to this as well.
Also, Fedora cloud images can be found at https://alt.fedoraproject.org/cloud/.
To launch an Ubuntu Core image from cdimage.ubuntu.com:
$ multipass launch http://cdimage.ubuntu.com/ubuntu-core/16/current/ubuntu-core-16-amd64.img.xz
Again, the defaults are used and the standard options apply. One really cool feature here is that xz encoded images are automatically extracted by Multipass.
One thing to note about Ubuntu Core images, the
multipass mount command will always fail because
sshfs cannot be installed in the instance.
The Multipass team has only tested Fedora cloud images and Ubuntu Core images, so any other types of images may or may not work. The team would be interested to know if they do or do not work.
As always, if you find any issues, please report them at https://github.com/CanonicalLtd/multipass/issues. Good luck!