This machine ID is already enabled with a different key or is non-unique

I have purchased new VPS and I wanted to enable Ubuntu live patch service for it. Unfortunately, the command canonical-livepatch enable [TOKEN] failed with this ugly error message:

This machine ID is already enabled with a different key or is non-unique.
Either “sudo canonical-livepatch disable” on the other machine, or regenerate a
unique /etc/machine-id on this machine with
“sudo rm /etc/machine-id /var/lib/dbus/machine-id && sudo systemd-machine-id-setup” :
{“error”: “Conflicting machine-id”}

I thought to myself “Ok, lets try the suggested solution”. What I did was to backup the file /etc/machine-id, than delete it and run suggested systemd command. I was surprised to see the newly generated UUID was the same! Consulting with man page of systemd-machine-id-setup command revealed that “If run inside a KVM virtual machine and a UUID is configured (via the -uuid option), this UUID is used to initialize the machine ID. The caller must ensure that the UUID passed is sufficiently unique and is different for every booted instance of the VM.”. Obviously, my new VPS provider did not ensure that and somebody else have the same machine ID on his/her VPS and enabled Ubuntu live patch for it.

In order to generate truly unique ID I decided to use dbus-uuidgen tool

rm -f /etc/machine-id
rm /var/lib/dbus/machine-id
dbus-uuidgen --ensure=/etc/machine-id
dbus-uuidgen --ensure

This last command implicitly uses /var/lib/dbus/machine-id as the file name and will copy the machine ID from the already-newly-generated /etc/machine-id. The file /var/lib/dbus/machine-id is specific to Debian systems only so you may not need it if you are using non-Debian based distro.

Changing the machine ID is a risky operation according to dbus-uuidgen man page:

If you try to change an existing machine-id on a running system, it will probably result in bad things happening. Don’t try to change this file. Also, don’t make it the same on two different systems; it needs to be different anytime there are two different kernels running.

It is good idea to reboot after changing the UUID and ensure everything is working as expected before making any other system changes you may lose. At least for me, changing the machine ID did not affect me negatively.


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