Cfrtjryk

On all my Red Hat Linux machines version 7.2 we saw that systemd-tmpfiles-clean.service is inactive:

systemctl status systemd-tmpfiles-clean.service

● systemd-tmpfiles-clean.service - Cleanup of Temporary Directories

   Loaded: loaded (/usr/lib/systemd/system/systemd-tmpfiles-clean.service; static; vendor preset: disabled)

   Active: inactive (dead) since Wed 2018-12-19 14:47:14 UTC; 12min ago

     Docs: man:tmpfiles.d(5)

           man:systemd-tmpfiles(8)

  Process: 34231 ExecStart=/usr/bin/systemd-tmpfiles --clean (code=exited, status=0/SUCCESS)

 Main PID: 34231 (code=exited, status=0/SUCCESS)



Dec 19 14:47:14 master02.uridns.com systemd[1]: Starting Cleanup of Temporary Directories...

Dec 19 14:47:14 master02.uridns.com systemd[1]: Started Cleanup of Temporary Directories.

It is strange that we saw the files and folders under /tmp,
and it seems that cleanup is performed every some time.

I searched on crontab or cronjob, but I did not find other cleanup jobs.

Am I missing something here?

Is it possible that in spite of the service being inactive, the cleanup is performed every couple of weeks?

  systemctl enable  systemd-tmpfiles-clean.service



The unit files have no [Install] section. They are not meant to be enabled

using systemctl.

Possible reasons for having this kind of units are:

1) A unit may be statically enabled by being symlinked from another unit's

   .wants/ or .requires/ directory.

2) A unit's purpose may be to act as a helper for some other unit which has

   a requirement dependency on it.

3) A unit may be started when needed via activation (socket, path, timer,

   D-Bus, udev, scripted systemctl call, ...).

We also saw a few folders that were real old, as

ls -ltr

total 137452

drwxr-xr-x 3 root      root         33 Jun 13  2017 Tools

drwx--x--x 3 root      root         16 Oct 12 09:33 systemd-private-74982d8a24254a1d8b8ec3b5c0d80a9b-httpd.service-QZqGLA

drwx--x--x 3 root      root         16 Oct 12 10:02 systemd-private-74982d8a24254a1d8b8ec3b5c0d80a9b-rtkit-daemon.service-BTcGY1

drwx--x--x 3 root      root         16 Oct 12 10:02 systemd-private-74982d8a24254a1d8b8ec3b5c0d80a9b-vmtoolsd.service-mQ1SXc

drwxr-xr-x 2 ambari    ambari       18 Oct 12 12:02 hsperfdata_ambari

drwx--x--x 3 root      root         16 Oct 12 12:17 systemd-private-74982d8a24254a1d8b8ec3b5c0d80a9b-cups.service-PnKaq8

drwx--x--x 3 root      root         16 Oct 12 12:17 systemd-private-74982d8a24254a1d8b8ec3b5c0d80a9b-colord.service-DNn470

-rwxr-xr-x 1 root      root      83044 Nov 18 17:27 Spark_Thrift.log

drwxr-xr-x 2 zookeeper hadoop       18 Nov 18 17:28 hsperfdata_zookeeper

-rwxr-xr-x 1 root      root        379 Nov 18 17:37 requests.txt

-rwxr-xr-x 1 root      root     137348 Nov 22 14:50 pp

-rwxr-xr-x 1 root      root        344 Nov 26 15:24 yy

prwx--x--x 1 root      root          0 Nov 29 21:26 hogsuspend

-rwxr-xr-x 1 root      root       1032 Dec  3 10:55 aa

From my machine:

more /lib/systemd/system/systemd-tmpfiles-clean.timer

#  This file is part of systemd.

#

#  systemd is free software; you can redistribute it and/or modify it

#  under the terms of the GNU Lesser General Public License as published by

#  the Free Software Foundation; either version 2.1 of the License, or

#  (at your option) any later version.



[Unit]

Description=Daily Cleanup of Temporary Directories

Documentation=man:tmpfiles.d(5) man:systemd-tmpfiles(8)



[Timer]

OnBootSec=15min

OnUnitActiveSec=1d

The rules are:

more /usr/lib/tmpfiles.d/tmp.conf

#  This file is part of systemd.

#

#  systemd is free software; you can redistribute it and/or modify it

#  under the terms of the GNU Lesser General Public License as published by

#  the Free Software Foundation; either version 2.1 of the License, or

#  (at your option) any later version.



# See tmpfiles.d(5) for details



# Clear tmp directories separately, to make them easier to override

v /tmp 1777 root root 10d

v /var/tmp 1777 root root 30d



# Exclude namespace mountpoints created with PrivateTmp=yes

x /tmp/systemd-private-%b-*

X /tmp/systemd-private-%b-*/tmp

x /var/tmp/systemd-private-%b-*

X /var/tmp/systemd-private-%b-*/tmp

You can ask systemd what a unit’s triggers are:

systemctl show -p TriggeredBy systemd-tmpfiles-clean

This will show that the systemd-tmpfiles-clean service is triggered by the systemd-tmpfiles-clean.timer timer. That is defined as

#  SPDX-License-Identifier: LGPL-2.1+

#

#  This file is part of systemd.

#

#  systemd is free software; you can redistribute it and/or modify it

#  under the terms of the GNU Lesser General Public License as published by

#  the Free Software Foundation; either version 2.1 of the License, or

#  (at your option) any later version.



[Unit]

Description=Daily Cleanup of Temporary Directories

Documentation=man:tmpfiles.d(5) man:systemd-tmpfiles(8)



[Timer]

OnBootSec=15min

OnUnitActiveSec=1d

Thus the service runs every day, and cleans directories up based on the tmpfiles.d configuration. See the associated man pages for details.

systemd-tmpfiles-clean.service is initiated by systemd-tmpfiles-clean.timer. You can inspect the timers with systemctl list-timers.

At least on Ubuntu 16.04, the systemd-tmpfiles-clean.timer is defined as

# Use `systemctl cat systemd-tmpfiles-clean.timer` to get your corresponding file

#

# /lib/systemd/system/systemd-tmpfiles-clean.timer

#  This file is part of systemd.

#

#  systemd is free software; you can redistribute it and/or modify it

#  under the terms of the GNU Lesser General Public License as published by

#  the Free Software Foundation; either version 2.1 of the License, or

#  (at your option) any later version.

[Unit]

Description=Daily Cleanup of Temporary Directories

Documentation=man:tmpfiles.d(5) man:systemd-tmpfiles(8)



[Timer]

OnBootSec=15min

OnUnitActiveSec=1d

Therefore, the timer will start systemd-tmpfiles-clean.service 15 minutes after boot, and every 24 hours afterwards.

For more information, see systemd.timer(5), systemd.service(5) and systemd.unit(5).