[systemd-devel] local-fs and remote-fs targets / passive active units

[Thomas HUMMEL]

On 4/28/20 5:36 PM, Thomas HUMMEL wrote:

> 3) regarding local-fs dans remote-fs targets : I'm not really sure if 
> any fits in either passive or active units.

Hello again,

regarding local-fs.target : is it legit for a custom service unit to 
pull it in with a Before=local-fs.target (no Wants or Requires) ?

For instance, I did create a simple oneshot test service (dodo.service) 
which just sleeps 20s stating Before=local-fs.target. I did that to 
emulate another service I created which formats an ssd and locally mount 
it (but outside of fstab so it would not get the automatic ordering 
dependency  that systemd-fstab-generator gives)

Note : this is on a statless host, so fstab states

rootfs / tmpfs defaults,size=3500M 0 0

1) it seem to create lots of ordering cycles like this one (among many)

dodo.service: Job systemd-tmpfiles-setup.service/start deleted to break 
ordering cycle starting with dodo.service/start

I can't really see why even if I see that systemd-tmpfiles-setup has 
also a Before=local-fs.target ordering dependency ?

2) given the job ultimately gets deleted because of this cycle, I cannot 
understand why it seems to be exectuted anyway :


[root at maestro-1002 systemd]# journalctl  | grep -i 
systemd-tmpfiles-setup.service
May 05 15:45:56 localhost systemd[1]: systemd-tmpfiles-setup.service: 
Installed new job systemd-tmpfiles-setup.service/start as 12
May 05 15:45:56 localhost systemd[1]: systemd-tmpfiles-setup.service: 
Passing 0 fds to service
May 05 15:45:56 localhost systemd[1]: systemd-tmpfiles-setup.service: 
About to execute: /usr/bin/systemd-tmpfiles --create --remove --boot 
--exclude-prefix=/dev
May 05 15:45:56 localhost systemd[1]: systemd-tmpfiles-setup.service: 
Forked /usr/bin/systemd-tmpfiles as 863
May 05 15:45:56 localhost systemd[1]: systemd-tmpfiles-setup.service: 
Changed dead -> start
May 05 15:45:56 localhost systemd[863]: systemd-tmpfiles-setup.service: 
Executing: /usr/bin/systemd-tmpfiles --create --remove --boot 
--exclude-prefix=/dev
May 05 15:45:57 localhost systemd[1]: systemd-tmpfiles-setup.service: 
Child 863 belongs to systemd-tmpfiles-setup.service.
May 05 15:45:57 localhost systemd[1]: systemd-tmpfiles-setup.service: 
Main process exited, code=exited, status=0/SUCCESS
May 05 15:45:57 localhost systemd[1]: systemd-tmpfiles-setup.service: 
Changed start -> exited
May 05 15:45:57 localhost systemd[1]: systemd-tmpfiles-setup.service: 
Job systemd-tmpfiles-setup.service/start finished, result=done
May 05 15:45:57 localhost systemd[1]: Got cgroup empty notification for: 
/system.slice/systemd-tmpfiles-setup.service
May 05 15:46:31 maestro-1002.maestro.pasteur.fr systemd[1]: 
systemd-tmpfiles-setup.service: Changed dead -> exited


-> this seems to be like an actual run and not only the queuing of a job 
into the transaction which would be discarded afterwards when the cycle 
is discovered ?

However once the host booted, I can see that at least one tmpfile (in a 
tmpfiles.d config file) has indeed not be created as it should be (and 
as it actually is when /usr/bin/systemd-tmpfiles --create --remove 
--boot --exclude-prefix=/dev is run manually).

May 05 15:46:32 maestro-1002.maestro.pasteur.fr systemd[1]: 
systemd-tmpfiles-setup.service: Installed new job 
systemd-tmpfiles-setup.service/stop as 84
May 05 15:46:32 maestro-1002.maestro.pasteur.fr systemd[1]: 
systemd-tmpfiles-setup.service: Changed exited -> dead
May 05 15:46:32 maestro-1002.maestro.pasteur.fr systemd[1]: 
systemd-tmpfiles-setup.service: Job systemd-tmpfiles-setup.service/stop 
finished, result=done
May 05 15:46:34 maestro-1002.maestro.pasteur.fr systemd[1]: 
dodo.service: Found dependency on systemd-tmpfiles-setup.service/start
May 05 15:46:34 maestro-1002.maestro.pasteur.fr systemd[1]: 
dodo.service: Job systemd-tmpfiles-setup.service/start deleted to break 
ordering cycle starting with dodo.service/start
May 05 15:51:45 maestro-1002 systemd[1]: Preset files say disable 
systemd-tmpfiles-setup.service.

Can you help me figure out my misunderstanding ?

Thanks for your help

--
Thomas HUMMEL