concurrent snapcraft builds with multipass provider

[Alireza Mohammadi]

When I try to build multiple snaps concurrently using the multipass provider, all the instances are assigned the same IPv4 address and hence all the builds are abruptly stopped without giving any useful information to debug. The output for the multipass list command looks like this:

Name State IPv4 Image
snapcraft-my-snap Running 10.30.202.6 Ubuntu Snapcraft builder for Core 18
snapcraft-testing Running 10.30.202.6 Ubuntu Snapcraft builder for Core 18

This behavior is unexpected and limits the capability of snapcraft for parallel builds on powerful machines. The issue is observed on both Ubuntu 18.04 and Ubuntu 20.04, with the snapcraft version 5.0 and multipass version 1.7.1.