Hi
Here we meet a question. After we upgrade mdadm from 4.1 to 4.2, we
execute :
systemctl start mdmonitor
the mdmonitor service failed to start when no raid device in
environment. error message are as follows:
mdmonitor.service - MD array monitor
Loaded: loaded (/usr/lib/systemd/system/mdmonitor.service;
enabled; vendor preset: enabled)
Active: failed (Result: protocol) since Thu 2023-05-11 10:52:32
CST; 5s ago
Process: 999741 ExecStartPre=mkdir -p /run/mdadm (code=exited,
status=0/SUCCESS)
Process: 999743 ExecStart=/sbin/mdadm --monitor $MDADM_MONITOR_ARGS
-f --pid-file=/run/mdadm/mdadm.pid (c>
May 11 10:52:32 localhost.localdomain systemd[1]: Starting MD array
monitor...
May 11 10:52:32 localhost.localdomain systemd[1]: mdmonitor.service:
Can't open PID file /run/mdadm/mdadm.pid>
May 11 10:52:32 localhost.localdomain systemd[1]: mdmonitor.service:
Failed with result 'protocol'.
May 11 10:52:32 localhost.localdomain systemd[1]: Failed to start MD
array monitor.
In the mdmonitor service file, type is set to forking and the PIDFILE
field is set. The systemd detection process is as follows:
(1)when the parent process exits, a signal is sent to systemd
(2)systemd wakes up and checks whether pidfile exists by PIDFILE field.
(3)If the pidfile file does not exist, the service status is set to fail.
In function Monitor code logic, after the parent process creates a
pidfile, before systemd detects the pidfile, the pidfile is deleted from
the child process. As a result, the systemd cannot detect the pidfile
and sets the service status to fail.
It is a problem for user, because the mdmonitor service status is fail.
If there is no RAID device in the environment, We want the service
status is expected to be inactive after the service is started. Can you
have any advice for this problem ?
