Build in nspawn containers

 Debspawn is a tool to build Debian packages in an isolated environment,
 using systemd-nspawn containers.
 By using containers, Debspawn can isolate builds from the host system
 much better than traditional chroot-based build environments could.
 .
 Debspawn is designed to be both easy to use by humans, as well as easy
 to integrate into an automated package build workflow.