on 2017-10-12 i’ve done a routine apt-get update; apt-get upgrade on a debian stretch vm that, among other services, runs opendkim service that adds a digital signature in the headers of the outgoing mails. during the update i was asked weather to keep or replace the /etc/opendkim.conf; as usual in such cases i’ve answered no which led to situation where the opendkimd no longer started. in /var/log/syslog i saw:
Oct 12 07:00:06 server opendkim: OpenDKIM Filter v2.11.0 terminating with status 0, errno = 0 Oct 12 07:01:19 server systemd: opendkim.service: PID file /var/run/opendkim/opendkim.pid not readable (yet?) after start: No such file or directory Oct 12 07:01:19 server opendkim: OpenDKIM Filter v2.11.0 starting (args: -x /etc/opendkim.conf) Oct 12 07:02:49 server systemd: opendkim.service: Start operation timed out. Terminating.
i’ve diffed the existing and proposed configs and noticed a new directive that was not present in my original, admitably archaic, file:
adding it and restarting the service resolved the problem.