$ sudo journalctl -u zfs-import-cache.service
-- Logs begin at Tue 2018-01-23 17:46:55 UTC, end at Tue 2018-01-23 17:49:18 UTC. --
Jan 23 17:46:58 ubuntu systemd[1]: Starting Import ZFS pools by cache file...
Jan 23 17:46:59 ubuntu zpool[640]: failed to open cache file: No such file or directory
Jan 23 17:46:59 ubuntu systemd[1]: zfs-import-cache.service: Main process exited, code=exited, status=1/FAILURE
Jan 23 17:46:59 ubuntu systemd[1]: zfs-import-cache.service: Failed with result 'exit-code'.
Jan 23 17:46:59 ubuntu systemd[1]: Failed to start Import ZFS pools by cache file.
This is on a host with no ZFS filesystems, so expected behavior is a no-op.
Confirmed to also affect bionic:
$ sudo journalctl -u zfs-import- cache.service cache.service: Main process exited, code=exited, status=1/FAILURE cache.service: Failed with result 'exit-code'.
-- Logs begin at Tue 2018-01-23 17:46:55 UTC, end at Tue 2018-01-23 17:49:18 UTC. --
Jan 23 17:46:58 ubuntu systemd[1]: Starting Import ZFS pools by cache file...
Jan 23 17:46:59 ubuntu zpool[640]: failed to open cache file: No such file or directory
Jan 23 17:46:59 ubuntu systemd[1]: zfs-import-
Jan 23 17:46:59 ubuntu systemd[1]: zfs-import-
Jan 23 17:46:59 ubuntu systemd[1]: Failed to start Import ZFS pools by cache file.
This is on a host with no ZFS filesystems, so expected behavior is a no-op.