Description of problem:

The comments on https://bugzilla.redhat.com/show_bug.cgi?id=1335997 also describe this issue. On startup, postfix will report the following:

2022-04-12T09:58:20.503458+02:00 mig003.cern.ch systemd[1]: Starting Postfix Mail Transport Agent...
2022-04-12T09:58:20.508915+02:00 mig003.cern.ch systemd[1]: Started Puppet agent.
2022-04-12T09:58:20.514957+02:00 mig003.cern.ch systemd[1]: Starting Dynamic System Tuning Daemon...
2022-04-12T09:58:20.526526+02:00 mig003.cern.ch restorecon[881]: /usr/sbin/restorecon: lstat(/var/spool/postfix/pid/master.pid) failed: No such file or directory

Version-Release number of selected component (if applicable):


How reproducible:

On a freshly installed machine, postfix will report the mentioned exception.

[root@juarezcs9 pid]# systemctl status postfix
● postfix.service - Postfix Mail Transport Agent
     Loaded: loaded (/usr/lib/systemd/system/postfix.service; enabled; vendor preset: disabled)
     Active: active (running) since Thu 2022-04-14 17:00:04 CEST; 1min 43s ago
    Process: 5018 ExecStartPre=/usr/sbin/restorecon -R /var/spool/postfix/pid/master.pid (code=exited, status=255/EXCEPTION)
    Process: 5019 ExecStartPre=/usr/libexec/postfix/aliasesdb (code=exited, status=0/SUCCESS)
    Process: 5021 ExecStartPre=/usr/libexec/postfix/chroot-update (code=exited, status=0/SUCCESS)
    Process: 5022 ExecStart=/usr/sbin/postfix start (code=exited, status=0/SUCCESS)
   Main PID: 5090 (master)
      Tasks: 3 (limit: 9919)
     Memory: 3.1M
        CPU: 378ms
     CGroup: /system.slice/postfix.service
             ├─5090 /usr/libexec/postfix/master -w
             ├─5091 pickup -l -t fifo -u
             └─5092 qmgr -l -t fifo -u

Apr 14 17:00:04 juarezcs9.cern.ch systemd[1]: Starting Postfix Mail Transport Agent...
Apr 14 17:00:04 juarezcs9.cern.ch restorecon[5018]: /usr/sbin/restorecon: lstat(/var/spool/postfix/pid/master.pid) failed: No such file or directory
Apr 14 17:00:04 juarezcs9.cern.ch postfix/postfix-script[5088]: starting the Postfix mail system
Apr 14 17:00:04 juarezcs9.cern.ch postfix/master[5090]: daemon started -- version 3.5.9, configuration /etc/postfix
Apr 14 17:00:04 juarezcs9.cern.ch systemd[1]: Started Postfix Mail Transport Agent.


Steps to fix it:
[root@juarezcs9 pid]# ls -Z /var/spool/postfix/pid/
system_u:object_r:postfix_var_run_t:s0 master.pid
[root@juarezcs9 pid]# service postfix stop
Redirecting to /bin/systemctl stop postfix.service
[root@juarezcs9 pid]# ls -Z /var/spool/postfix/pid/
[root@juarezcs9 pid]# postfix start
postfix/postfix-script: starting the Postfix mail system
[root@juarezcs9 pid]# pwd
/var/spool/postfix/pid
[root@juarezcs9 pid]# ls -Zd .
system_u:object_r:var_run_t:s0 .
[root@juarezcs9 pid]# ls -Z /var/spool/postfix/pid/
unconfined_u:object_r:var_run_t:s0 master.pid
[root@juarezcs9 pid]# postfix stop
postfix/postfix-script: stopping the Postfix mail system
[root@juarezcs9 pid]# ls -Z /var/spool/postfix/pid/
unconfined_u:object_r:var_run_t:s0 master.pid
[root@juarezcs9 pid]# service postfix start
Redirecting to /bin/systemctl start postfix.service
[root@juarezcs9 pid]# ls -Z /var/spool/postfix/pid/
unconfined_u:object_r:postfix_var_run_t:s0 master.pid
[root@juarezcs9 pid]# systemctl status postfix
● postfix.service - Postfix Mail Transport Agent
     Loaded: loaded (/usr/lib/systemd/system/postfix.service; enabled; vendor preset: disabled)
     Active: active (running) since Thu 2022-04-14 17:03:23 CEST; 6s ago
    Process: 5239 ExecStartPre=/usr/sbin/restorecon -R /var/spool/postfix/pid/master.pid (code=exited, status=0/SUCCESS)
    Process: 5240 ExecStartPre=/usr/libexec/postfix/aliasesdb (code=exited, status=0/SUCCESS)
    Process: 5242 ExecStartPre=/usr/libexec/postfix/chroot-update (code=exited, status=0/SUCCESS)
    Process: 5243 ExecStart=/usr/sbin/postfix start (code=exited, status=0/SUCCESS)
   Main PID: 5311 (master)
      Tasks: 3 (limit: 9919)
     Memory: 3.1M
        CPU: 369ms
     CGroup: /system.slice/postfix.service
             ├─5311 /usr/libexec/postfix/master -w
             ├─5312 pickup -l -t fifo -u
             └─5313 qmgr -l -t fifo -u

Additional info:

It seems as if unless initially started with "postfix start", the systemd unit will report this issue.