This appears to be a regression in systemd. I extracted the unit file we're trying to link and manually linked it through systemctl and it succeeded with 222-2ubuntu1, but failed with 223-1ubuntu1:
ubuntu@cherylj-wily4:~$ apt-cache policy systemd systemd: Installed: 222-2ubuntu1 Candidate: 223-1ubuntu1 Version table: 223-1ubuntu1 0 500 http://nova.clouds.archive.ubuntu.com/ubuntu/ wily/main amd64 Packages *** 222-2ubuntu1 0 100 /var/lib/dpkg/status root@cherylj-wily4:~$ sudo systemctl link /var/lib/juju/init/juju-db-ubuntu-local/juju-db-ubuntu-local.service Created symlink from /etc/systemd/system/juju-db-ubuntu-local.service to /var/lib/juju/init/juju-db-ubuntu-local/juju-db-ubuntu-local.service. ubuntu@cherylj-wily4:~$ sudo systemctl disable /var/lib/juju/init/juju-db-ubuntu-local/juju-db-ubuntu-local.service Removed symlink /etc/systemd/system/juju-db-ubuntu-local.service. ubuntu@cherylj-wily4:~$ sudo apt-get upgrade ... ubuntu@cherylj-wily4:~$ apt-cache policy systemd systemd: Installed: 223-1ubuntu1 Candidate: 223-1ubuntu1 Version table: *** 223-1ubuntu1 0 500 http://nova.clouds.archive.ubuntu.com/ubuntu/ wily/main amd64 Packages 100 /var/lib/dpkg/status ubuntu@cherylj-wily4:~$ sudo systemctl link /var/lib/juju/init/juju-db-ubuntu-local/juju-db-ubuntu-local.service Failed to execute operation: Unit name /var/lib/juju/init/juju-db-ubuntu-local/juju-db-ubuntu-local.service is not valid. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1480310 Title: dbus link request failed for service FOO: Unit name FOO is not valid. Status in juju-core: Triaged Status in systemd package in Ubuntu: New Bug description: As seen in http://reports.vapour.ws/releases/2936/job/local-deploy-wily-amd64/attempt/136 Juju cannot bootstrap on wily because ERROR juju.service.systemd service.go:149 dbus link request failed for service "juju-db-jenkins-local-deploy-wily-amd64": Unit name /var/lib/juju/init/juju-db-jenkins-local-deploy-wily-amd64/juju-db-jenkins-local-deploy-wily-amd64.service is not valid. This error first occurred after the wily-slave got package updates. The released jujus get the same errors as the jujus under test. This issue is probably an Ubuntu packaging break. I am making the test non-voting since we can see table 1.24.3 no longer works. To manage notifications about this bug go to: https://bugs.launchpad.net/juju-core/+bug/1480310/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp