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user24601
Asked: 2016-05-29 19:08:30 +0800 CST

Create a directory under /var/run at boot

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I had a daemon that needed its own dir in /var/run for its PID file with write permission granted to the daemon's user.

I found I could create this dir with these commands:

# mkdir /var/run/mydaemon

Then I could change its ownership to the user/group under which I wished to run the process:

# chown myuser:myuser /var/run/mydaemon

But this dir would be GONE whenever I issue a reboot! How do I get this dir to create every time the machine boots?

linux daemon centos7 systemd startup-scripts

2 Answers

  1. Best Answer

    There are two alternatives to have systemd create directories under /var/run / /run.

    Typically the easiest is to declare a RuntimeDirectory in the unit file of your service. Example:

    RuntimeDirectory=foo

    This will create /var/run/foo for a system unit. (Note: DO NOT provide a full path, just the path under /var/run) For full docs please see the appropriate entry in systemd.exec docs.


    For runtime directories that require more complex or different configuration or lifetime guarantees, use tmpfiles.d and have your package drop a file /usr/lib/tmpfiles.d/mydaemon.conf :

    #Type Path            Mode UID      GID    Age Argument
d     /run/mydaemon   0755 myuser myuser   -   -

    See the full tmpfiles.d docs here.

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  2. I created a service that would make the dir at start:

    vim /etc/systemd/system/mydaemon-helper.service

    The contents of /etc/systemd/system/mydaemon-helper.service:

    [Unit]
Description=MyDaemon Helper Simple Service
After=network.target

[Service]
Type=simple
ExecStartPre=-/usr/bin/mkdir /var/run/mydaemon
ExecStart=/usr/bin/chown myuser:myuser /var/run/mydaemon
Restart=on-abort


[Install]
WantedBy=multi-user.target

    Then I started this service:

    systemctl start mydaemon-helper

    systemctl status mydaemon-helper

    Output:

    [root@alpha etc]# systemctl status mydaemon-helper.service
● mydaemon-helper.service - MyDaemon Helper Simple Service
   Loaded: loaded (/etc/systemd/system/mydaemon-helper.service; disabled; vendor preset: disabled)
   Active: inactive (dead)

May 28 20:53:50 alpha systemd[1]: Starting MyDaemon Helper Simple Service...
May 28 20:53:50 alpha systemd[1]: Started MyDaemon Helper Simple Service.

    Lastly I told the system to load it on startup:

    systemctl enable mydaemon-helper

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