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Machine-ID and journald

Today I learned that journald will no longer start when /etc/machine-id is removed. journald takes care of the logging in a modern Linux system following the freedesktop standards. The machine-id is a unique ID for each system that the freedesktop standard considers important to differentiate the machine. It’s usually created on first boot up by systemd-machine-id-setup and will stay the same throughout the lifetime of the system.

I came across this while working on a RHEL system image and figuring out some software dependencies. To make images working properly I decided to delete the machine-id file. Later noticing that logs were no longer available due to journald refusing to start. You will notice that journalctl -xe will show you the following line at the end “systemd-journal[103]: Journal stopped”, which is journald exiting after dracut hands over the system.