Systemd 247-RC1 Released With Systemd-OOMD, Systemd-Homed Now Defaults To Btrfs

The first release candidate of systemd 247 is now available for testing and it's a huge feature release.

This big systemd 247 release is introducing systemd-oomd for out-of-memory daemon handling, systemd-homed now defaults to using Btrfs, there is a new capability with systemd of secure credentials handling, and much more. Below is a look at the highlights for systemd 247:

- The new systemd-oomd service has been added for monitoring resource contention and can kill processes when memory/swap pressure is above the defined limits. For now this is experimental and just enabled in the developer mode.

- Systemd-homed defaults to using the Btrfs file-system when available for creating home directories in LUKS volumes. The DefaultFileSystemType= option for homed.conf remains available for changing off the default/ Btrfs was chosen since it can grow and shrink the file-system online.

- Systemd's system services now supports "credentials" logic as a means of passing privileged data to services in a safe and secure manner. The intended use-case is around passwords, cryptographic keys, and other per-service private data handling but also possibly less privileged data like usernames and certificates. Systemd-nspawn is among the early users of systemd credentials.

- JSON user records for systemd-homed adds support for "recovery keys" as a means of secondary passphrases for unlocking accounts/home directories.

- Run-time dependencies on a number of libraries are now loaded using dlopen() when found on the system. This allows minimizing the possible dependencies needed by systemd and for constructing more minimal operating system images.

- The systemd-dissect tool for inspecting operating system disk images has now been moved to /usr/bin in being promoted to being an officially supported tool with a stable interface.

- The systemd-repart partitioner can now optionally dump its output in JSON form.

- Setting the SYSTEMD_RDRAND=0 environment variable will now disable RdRand CPU instruction usage even with supported CPUs.

Systemd 247 RC1 is available for download from GitHub.