Where the process of the service?

debugcn Published at Dev

Peter Krauss

At UBUNTU, service postgresql status lists

  Process: 18534 ExecStart=/bin/true (code=exited, status=0/SUCCESS)
 Main PID: 18534 (code=exited, status=0/SUCCESS)

but when I test sudo ps -ax | grep 18534 nothing is listed.

NOTES

EDIT1 for @DanielB request, but I need a simple command that shows any service PID.

Here a dump more /lib/systemd/system/postgresql.service,

# systemd service for managing all PostgreSQL clusters on the system. This
# service is actually a systemd target, but we are using a service since
# targets cannot be reloaded.

[Unit]
Description=PostgreSQL RDBMS

[Service]
Type=oneshot
ExecStart=/bin/true
ExecReload=/bin/true
RemainAfterExit=on

[Install]
WantedBy=multi-user.target

EDIT2

The PostgreSQL above was my localhost server... Now I am testing in a "new, clean and shine" DigitalOcean Droplet with UBUNTU 16 LTS and Postgresql 9.X...

root@myServer:~# service postgresql status
● postgresql.service - PostgreSQL RDBMS
   Loaded: loaded (/lib/systemd/system/postgresql.service; enabled; vendor preset: enabled)
   Active: active (exited) since Dom 2016-12-18 17:47:09 UTC; 2 weeks 4 days ago
 Main PID: 8703 (code=exited, status=0/SUCCESS)
    Tasks: 0
   Memory: 0B
      CPU: 0
   CGroup: /system.slice/postgresql.service

Dez 18 17:47:09 myServer systemd[1]: Starting PostgreSQL RDBMS...
Dez 18 17:47:09 myServer systemd[1]: Started PostgreSQL RDBMS.
Dez 18 17:47:14 myServer systemd[1]: Started PostgreSQL RDBMS.


root@myServer:~# sudo ps -ax | grep  8703
 3702 pts/0    S+     0:00 grep --color=auto 8703

root@myServer:~# sudo service postgresql restart

root@myServer:~# sudo ps -ax | grep  8703
 3760 pts/0    S+     0:00 grep --color=auto 8703


root@myServer:~# service postgresql status
● postgresql.service - PostgreSQL RDBMS
   Loaded: loaded (/lib/systemd/system/postgresql.service; enabled; vendor preset: enabled)
   Active: active (exited) since Sex 2017-01-06 16:06:07 UTC; 8s ago
  Process: 3755 ExecStart=/bin/true (code=exited, status=0/SUCCESS)
 Main PID: 3755 (code=exited, status=0/SUCCESS)

Jan 06 16:06:07 myServer systemd[1]: Starting PostgreSQL RDBMS...
Jan 06 16:06:07 myServer systemd[1]: Started PostgreSQL RDBMS.


sudo ps -ax | grep  3755
 3780 pts/0    S+     0:00 grep --color=auto 3755

user1686

There is none, because as you can see yourself from the unit's contents, postgresql.service does not actually start any daemon. It exists merely as a 'parent' service to group together various instances of [email protected] (i.e. to reload all of them at once). Instead take a look at: