sysdb

sysdb is a simple database holding information relevant to system deployment, including

a MAC to FQDN mapping
whether to boot from local disk or install
if installation is requested, which distribution/release to install
which environment a system belongs to, and who can manage the environment
arbitrary key-value pairs which can be used to store additional information like the Puppet role of a system.

sysdb runs on the server, ie. sysdb.psi.ch (production).