[systemd-devel] [SPAM]Re: Mount units with After=autofs.service cause ordering cycles

[Lennart Poettering]

On Do, 31.10.19 14:09, John Florian (jflorian at doubledog.org) wrote:

> > > # /etc/systemd/system/var-www-pub.mount
> > > [Unit]
> > > Description=mount /pub served via httpd
> > > Requires=autofs.service
> > > After=autofs.service
> > >
> > > [Mount]
> > > What=/mnt/pub
> > > Where=/var/www/pub
> > > Options=bind,context=system_u:object_r:httpd_sys_content_t
> > >
> > > [Install]
> > > WantedBy=multi-user.target
> > >
> > > ~~~
> > >
> > > The above worked for a long time, but once again a `dnf upgrade` seems to
> > > have broken things because now I have a ordering cycle that systemd must
> > > break.  Since I haven't changed my mount units, my ability to mesh with
> > > those shipped by the OS proves fragile. I'm deliberately avoiding too much
> > > detail here because it would seem that there should be a relatively simple
> > > solution to this general sort of task -- I just can't seem to discover it.
> > > Any recommendations that don't involve an entirely different approach?
> > What precisely is the ordering cycle you are seeing? It's usually
> > dumped along with the log message.
>
> systemd[1]: local-fs.target: Found ordering cycle on var-www-pub.mount/start
> systemd[1]: local-fs.target: Found dependency on autofs.service/start
> systemd[1]: local-fs.target: Found dependency on rpc-statd.service/start
> systemd[1]: local-fs.target: Found dependency on network-online.target/start
> systemd[1]: local-fs.target: Found dependency on network.target/start
> systemd[1]: local-fs.target: Found dependency on
> NetworkManager.service/start
> systemd[1]: local-fs.target: Found dependency on sysinit.target/start
> systemd[1]: local-fs.target: Found dependency on
> systemd-update-done.service/start
> systemd[1]: local-fs.target: Found dependency on local-fs.target/start
> systemd[1]: local-fs.target: Job var-www-pub.mount/start deleted to break
> ordering cycle starting with local-fs.target/start

The ordering dep between local-fs.target and var-ww-pub.mount is what
you have to get rid of to remove the cycle. Set:

…
[Unit]
DefaultDependencies=no
Conflicts=umount.target
Before=umount.target
…
[Install]
WantedBy=remote-fs.target
…

i.e. make this a dep of remote-fs.target, not the implicit
local-fs.target, so that we don#t pull it in early boot, but only
during late boot, before remote-fs.target.

Lennart

--
Lennart Poettering, Berlin