Systemd

systemd is being added to postmarketOS (in addition to OpenRC), as announced in this blog post.

How to build your own systemd-based postmarketOS images

The steps here will change until it is fully integrated! See pmaports#2632 for details. Trying this out in the current stage is for advanced users who know what they are doing!

Configure pmbootstrap for systemd

Clone pmbootstrap from git
Go to your local pmaports clone (default path ~/.local/var/pmbootstrap/cache_git/pmaports otherwise displayed with pmbootstrap config aports)
Then, run the following commands

git fetch 
git checkout -b master_staging_systemd

Run pmbootstrap init, select systemd and select your device
Run pmbootstrap config systemd always

Build the image

Run pmbootstrap install as usually.

Undo configuration for systemd

Checkout master again in pmaports

Debugging

Sometimes boot-up can hang waiting for a required service to start, before any VT/console is available for login/debug. The systemd debug shell can be enabled by adding systemd.debug-shell=1 to the kernel cmdline, and a shell will be available on VT9 when systemd starts.

Reporting bugs

Bugs should be should include the systemd gitlab label when they are filed, so that they are easy to find.

Contributing patches

Thank you for helping to improve systemd support in postmarketOS! Merge requests should be submitted with the target branch set to master_systemd_staging, and they should be labeled with the gitlab label systemd so that they are easy to find for review.

For adding systemd services and other unit files, see Systemd_services

Matrix / IRC channel

We have a dedicated Matrix and IRC channel for integrating systemd with postmarketOS, feel free to join if you are interested in contributing!

Managing Services in pmaports

Summary

This describes the design for configuring and maintaining systemd service autostart preferences in pmaports. It's intended to be used by pmaports package maintainers. It may also be helpful for system admins who would like to understand how pmOS performs autostart configuration for systemd user and system services.

Goals

Users should have ultimate control in how their system is configured and pmOS maintainers need a reliable, easy, and consistent way to provide default configuration for users on all device and UI combinations that we support.

With systemd, maintainers and users have a lot more options for specifying service autostart preferences. We found that some of these options can create service autostart config conflicts between users and pmOS package maintainers. For example, users might run systemctl disable foo and a package update might systemctl enable foo and override the user's preferences. This has happened in the past with our openrc config. The following requirements were used to find a design that prevents (or greatly reduces) these types of conflicts:

Allow pmOS components (such as UI and device packages) to specify default autostart preferences.
Allow users to override preferences using well known methods (e.g. systemctl disable ...)
Packages should not override user config
Use something similar to other distros that also solve this problem
Allow package managers to conditionally enable/disable autostarted services on package upgrade, useful for replacing one service with another.

Design

Systemd service autostart config is handled using systemd's preset feature. Some major distros, like Fedora, use systemd presets. A lot of the following design was inspired by how other distros use this. Presets, when used in the following way, allow us to meet all of the previously stated goals.

The general overview is:

pmOS packages (currently postmarketos-base-systemd) install systemd preset config for services, for postmarketOS
packages that install systemd unit files run an install script macro to apply preset config on installation
Those same packages also run a different macro on uninstall to clean up symlinks

Distro system and user service presets are installed by the postmarketos-base-systemd package. Other packages may provide presets too, but care must be taken to ensure that service packages using the systemd install script macros must be installed after any package providing a preset config for that service. If this cannot be guaranteed, then the expected preset may not be applied.

Service packages that install systemd unit files should use post-install and pre-deinstall install script macros when those unit files include an [Install] section. The macros are provided in the file /usr/share/systemd/systemd-apk-macros.sh, this file is installed by the systemd package. The relevant install scripts are expected to source this file. There are two functions in this file, one for each type of install script:

systemd_service_post_install and systemd_service_pre_deinstall. Both scripts accept either user or system as the first param (for type of service), and then a list of services.

Example using ficticious foo service, where foo.service and foo@.service unit files are installable:

$ cat foo-systemd.post-install
$!/bin/sh
. /usr/share/systemd/systemd-apk-macros.sh
systemd_service_post_install system foo foo@bar

$ cat foo-systemd.pre-deinstall
$!/bin/sh
. /usr/share/systemd/systemd-apk-macros.sh
systemd_service_pre_deinstall system foo foo@bar

Currently, if service files are added in the `systemd-services` package in pmaports, adding a new variable for the service in step 5 of the systemd-services/APKBUILD will cause that package to generate the necessary install scripts automatically.

Subpages

Systemd/services