Overview

This is the set of scripts and service definitions used on all of my Linux boxes. You can use this repository as a starting point for your machines, or you can copy individual service directories as needed. Keep in mind that the format extensions below are provided by the scripts in this repository, not by s6-rc, so you will have to "de-sugar" run scripts taken from this repository.

These scripts and service directories were developed on gentoo-musl, but they should work on any Linux distribution (possibly with minor modification).

For examples of user-level service definitions, also managed by similar scripts and s6-rc, see https://github.com/smaeul/rc-user.

Dependencies

1. The s6/s6-linux-init/s6-rc software suite and its dependencies.
2. Standard POSIX command-line utilities, plus install and a date with GNU extensions. These can be provided by coreutils/psmisc/util-linux or busybox.

Installation

1. Clone this repository to /etc/rc. Putting it somewhere else is fine, but requires modifying the init and update scripts (as well as the service dirs in run-image) to point to the correct location.
2. Configure the desired set of services (see below). A supervisor will be run for all services except those with a disabled marker, but only those services contained in the default bundle (and their dependencies) will be started at boot. Adding the disabled marker file will automatically remove a service from all bundles.
3. Create required users. The fd holder is run as nobody, and all automatically-generated logger services run under the log user (this can be changed in the update script and the s6-svscan-log run script). Some services may require their own individual users; see their respective run scripts.
4. Run /etc/rc/update to compile the service database.
5. Add init=/etc/rc/init to your kernel command line (replacing any existing init path).
6. Reboot.

Configuration

All of the s6 and s6-rc documentation applies here. In addition, the update script implements a few extensions to the service directory format.

disabled

Presence of this file causes the service to be entirely excluded from the compiled database. No supervisor will be created for it at runtime, and it will be removed from all bundles.

instances

This file contains a list of "instances" (variants) of the service, with one instance name on each line. If this file is present, the update script creates a copy of the service for each instance, suffixed with the (lightly escaped) instance name, and with all occurrences of the string %I in the service directory replaced by the instance name. The update script also generates a bundle (named the same as the original service) containing all of the instantiated services.

Note that if the instances file is present and empty, only an empty bundle is created. This ensures dependencies are always satisfied, even if no instances of the service are needed.

logdir

The content of this file (one line) specifies a subdirectory of /var/log where logs for this service are stored. If this file is present, the update script creates a logger service and a pipeline connecting this service to its logger.

Troubleshooting

• An early getty is created on tty4 by default. If you still cannot log in, and you use PAM, ensure that /var is writable.
• Logs for everything that doesn't have a logdir file, including s6-rc itself, are in /run/uncaught-logs.

Updates

Simply run /etc/rc/update after making changes to the source files. Occasionally, you may wish to clean out old compiled databases. They are stored in directories /etc/rc/compiled.${TIMESTAMP}. Be sure not to delete the current (latest) compiled database, as it is required for s6-rc to function.

If, for some reason, you need to recreate the database on disk without touching the live database, remove also the compiled symlink. Note that this will prevent using s6-rc-update until you reboot.