I got a PXE server that was able to netboot Debian 9.5. I wanted to start playing with Buster/Sid, and completely forgot how to convert the machine.

For more information on Sid, check out here. But the most relevant thing about it is this:

The Unstable repositories are updated every 6 hours. You can upgrade with apt-get dist-upgrade, taking all the necessary precautions beforehand of course.

I did some googling and found this page on how to do it, but figured I’d capture it for myself here.

Make sure that your Debian 9.5 machine is as up to date as possible:

NOTE: you need to be root for all of this.

apt-get update
apt-get upgrade
apt-get dist-upgrade

Next, convert the sources.list from stretch to buster.

sed -i 's/stretch/buster/g' /etc/apt/sources.list

Update the apt cache with the new sources.

apt-get update

Update the machine fully:

apt-get upgrade
apt-get dist-upgrade

Verify that the update has succeeded:

cat /etc/debian_version

I’d reboot now to make sure everything comes up as expected.