bootc-root-setup.service

Description

This service runs in the initramfs to set up the root filesystem when composefs is enabled. It is only activated when the composefs kernel command line parameter is present.

The service performs the following operations:

Mounts the composefs image specified in the kernel command line
Sets up /etc and /var directories from the deployment state
Optionally configures transient overlays based on the configuration file
Prepares the root filesystem for switch-root

This service runs after sysroot.mount and ostree-prepare-root.service, and before initrd-root-fs.target.

Configuration File

The service reads an optional configuration file at /usr/lib/composefs/setup-root-conf.toml. If this file does not exist, default settings are used.

WARNING: The configuration file format and composefs integration are experimental and subject to change.

Configuration Options

The configuration file uses TOML format with the following sections:

[root]

transient (boolean): If true, mounts the root filesystem as a transient overlay. This makes all changes to / ephemeral and lost on reboot. Default: false.

[etc]

mount (string): Mount type for /etc. Options: "none", "bind", "overlay", "transient". Default: "bind".
transient (boolean): Shorthand for mount = "transient". Default: false.

[var]

mount (string): Mount type for /var. Options: "none", "bind", "overlay", "transient". Default: "bind".
transient (boolean): Shorthand for mount = "transient". Default: false.

Example Configuration

[root]
transient = false

[etc]
mount = "bind"

[var]
mount = "overlay"

Experimental Status

The composefs integration, including this service and its configuration file format, is experimental and subject to change.

Version

v1.11.0

bootc-root-setup.service - Man Page