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Custom Phase Script

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Benn edited this page Nov 8, 2022 · 3 revisions

Overview

A Custom Phase Script is a script provided by you. You put all the commands in the Custom Phase Script that you want to have done to the IMG.

The Custom Phase Script is called 3 times: Once for Phase 0, once for Phase 1, and once after Phase 1 has completed. The first argument indicates the current phase ("0", "1", or "post-install"). The Custom Phase Script needs to be aware of the phase, as there are contextual differences:

  • In Phase 0, the host file system is fully available. The IMG file is mounted on /mnt/sdm, so all references to the IMG file system must be appropriately referenced by prefacing the directory string with /mnt/sdm. This enables the Custom Phase script to copy files from the host file system into the IMG file.

  • In Phase 1 and post-install (both inside nspawn) the script runs in the context of the IMG. This is where you install and configure any additional or apps with special install requirements. In both Phase 1 and post-install, the host file system is not available at all. Thus, if a file is needed in Phase 1, Phase 0 must copy it into the IMG. References to /mnt/sdm will fail in Phase 1.

If a Custom Phase Script wants to run a script at boot time, even if --bootscripts is not specified, the Custom Phase script should put the script in /etc/sdm/0piboot in the IMG and named 0*-*.sh (e.g., 010-customize-something.sh). These scripts are always run by FirstBoot.

The best way to build a Custom Phase Script is to start with the example Custom Phase Script sdm-customphase, and extend it as desired.

Command line switches

  • --cscript scriptname — Specifies the path to your Custom Phase Script, which will be run as described in the Custom Phase Script section below.
  • --csrc /path/to/csrcdir — A source directory string that can be used in your Custom Phase Script. One use for this is to have a directory tree where all your customizations are kept, and pass in the directory tree to sdm with --csrc.
  • --custom[1-4] — 4 variables (custom1, custom2, custom3, and custom4) that can be used to further customize your Custom Phase Script.
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