Starting up programs automatically upon system boot

If your package implements a server or daemon, you will probably want it to be started automatically when the system boots.

The SME Server boots in runlevel 7, so you can get an idea of the startup processes by listing the contents of /etc/rc.d/rc7.d.

These are similar to the init scripts you may be familiar with from other Linux systems, with one important differnce. Instead of pointing to scripts within /etc/rc.d/init.d, all of those init entries are links to /etc/rc.d/init.d/e-smith-service. This is a wrapper which checks the configuration database to see if the service is supposed to be running and if so, starts the service from /etc/rc.d/init.d/whatever.

So for example, you might have:

S90squid -> /etc/rc.d/init.d/e-smith-service

The e-smith-service script looks up the name it was invoked with (S90squid), drops the prefix (leaving squid), checks the configuration database for the "squid" service, then if it's supposed to run, does:

/etc/rc.d/init.d/squid start

Here is the step-by-step procedure for making your package start up a program called myserver at boot time.

  1. First, create the traditional init script /etc/rc.d/init.d/myserver which can be run with the command-line arguments "start" or "stop" to perform the appropriate action on the server. Look at other init scripts in the same directory for examples. This script should be included in your RPM.

    Note: If your service is managed by runit, all you need is a link to the daemontools script.

  2. Second, create a symbolic link as shown below, choosing the two-digit number after the letter S to control the startup order of the server programs. Include this symbolic link in your RPM.

    /etc/rc.d/rc7.d/S55myserver -> /etc/rc.d/init.d/e-smith-service

    These two steps are typical for any Linux/Unix server application, except that the symbolic link traditionally points directly to the init script, rather than to e-smith-service. Remember, we want to link to e-smith-service to ensure that a disabled service does not start at boot time.

  3. Third, let's assume for now that myserver should be enabled by default, and so start at boot time. You just need to create some properties in the configuration database to make that happen:

    cd /etc/e-smith/db/configuration/defaults
    mkdir myserver
    cd myserver
    echo service >type
    echo enabled >status

    For testing, you will also need to run initialize-default-databases to load these new defaults.

  4. Your RPM can also start the service in the %post section, but you need to be very careful to only do this in run-level 7. The same %post section is run during installation from CDROM, and we do not want services started during that installation. They will most likely fail and may cause the CD install to fail.

All of these steps result in the server starting automatically upon installation of the RPM, and whenever the server is rebooted.

Care should also be taken for the RPM to uninstall cleanly. The service should be stopped and marked not to be restarted and so your RPM should contain the following lines in the pre-uninstallation script:

/sbin/e-smith/db configuration setprop myserver status disabled
/etc/rc7.d/S55myserver stop

The /service/myserver symbolic link is owned by the RPM, and when it is removed, runsvdir will soon notice and kill the runsv supervision process. The final true command ensures that a failure from the other commands won't cause the removal of the RPM to fail. Note that these steps cannot be in the post-uninstallation script, since some of the required files may have been removed by that time.