As of launchpad-buildd 149, deployed to production on 2017-09-04, the
following changes are effective on Launchpad's build farm:
* sbuild (used to build .debs from source packages) uses its schroot
mode to perform chroot operations rather than sudo. This is closer
to how Debian builders behave and to how developers typically run
sbuild interactively, and it means that the inactivity timeout
actually works properly rather than leaving builds in a state where
they have to be cancelled manually.
There are some small differences in the environment observed from
inside a build, of which the most important are probably that HOME is
now set to a nonexistent directory, and V=1 is set to cause various
build systems to be more verbose (we made this change in 2014 but it
was lost somewhere along the way). See  for more details.
* Snaps and live filesystems are now built in LXD containers rather
than in chroots, laying the groundwork for them to be able to install
snaps as build-dependencies.
At the moment the only known regressions from this are in some corner
cases of live filesystem building (powerpc and CPC). Let us know if you
see anything else amiss, although as usual please try to reproduce
problems locally before attributing them to the build environment.