Systemd 249 Released With New Option For Simple Whole-File-System A/B Updates

Written by Michael Larabel in systemd on 7 July 2021 at 02:12 PM EDT. 1 Comment
Systemd 249 has been promoted to stable as the newest version of this Linux init system.

Systemd 249 brings plenty of changes as usual with new systemd releases. One of the notable changes is around being able to carry out whole-file-system A/B updates. As explained in the change-log, "When operating on disk images via the --image= switch of various tools (such as systemd-nspawn or systemd-dissect), or when udev finds no 'root=' parameter on the kernel command line, and multiple suitable root or /usr/ partitions exist in the image, then a simple comparison inspired by strverscmp() is done on the GPT partition label, and the newest partition is picked. This permits a simple and generic whole-file-system A/B update logic where new operating system versions are dropped into partitions whose label is then updated with a matching version identifier."

Some of the other systemd 249 highlights include:

- Systemd-sysusers and systemd-firstboot now supports querying information from the credential subsystems.

- The systemd-repart partition configurations have a new "MakeDirectories=" option to create arbitrary directories inside file-systems as they are created.

- The /etc/os-release file has new optional variables of IMAGE_VERSION= and IMAGE_ID= around operating system image information.

- A new udev hardware database for FireWire devices.

- The native Journal protocol is now properly documented.

- Various DHCP server improvements.

- systemd-detect-virt can now correctly identify Amazon EC2 environments.

More details on all of the systemd 249 changes and source downloads via GitHub.
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