When rolling out the systemd security update for jessie, I skipped labtestpuppetmaster2001, something is broken with the config and/or package state, when trying to upgrade udev/systemd it would even attempt to switch to sysvinit!
This is most probably caused by the openstack-mitaka component having systemd included.
# apt-get install libudev1 udev systemd systemd-sysv libsystemd0 Reading package lists... Done Building dependency tree Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: udev : Breaks: ifupdown (< 0.8.5~) Breaks: systemd (< 224-2) but 215-17+deb8u13 is to be installed E: Unable to correct problems, you have held broken packages. # apt-get install udev Reading package lists... Done Building dependency tree Reading state information... Done The following extra packages will be installed: ifupdown libsystemd0 libudev1 sysvinit-core Suggested packages: ppp rdnssd The following packages will be REMOVED: systemd systemd-sysv The following NEW packages will be installed: sysvinit-core The following packages will be upgraded: ifupdown libsystemd0 libudev1 udev 4 upgraded, 1 newly installed, 2 to remove and 36 not upgraded. Need to get 1,469 kB of archives. After this operation, 13.3 MB disk space will be freed. Do you want to continue? [Y/n] ^C