Swap Docker CRI with containerd

[onedr0p]

Using Docker isn't really needed, or is it? A couple concerns are:

• Internal DNS, I use a separate device running PiHole for this, does containerd allow setting a DNS like Docker?
• Building container images if I ever start using DroneCI maybe with https://github.com/GoogleContainerTools/kaniko

[onedr0p]

I did this for my two worker nodes, one at a time:

kubectl drain <node>
kubectl delete node <node>

# on the node itself I ran
docker system prune -a --force
sudo reboot
k3s-killall.sh
k3s-uninstall.sh
k3s-agent-uninstall.sh
sudo reboot
docker system prune -a --force
sudo apt remove --purge docker-ce
sudo apt auto-remove
# removed docker repo from /etc/apt/sources.list
sudo apt update
sudo reboot
# joined the nodes back with k3sup without the `--docker` flag

Now I am unsure if doing this on my master and storage nodes will have a negative impact.

[carpenike]

Doing your master would probably brick ya wouldn't it?

Storage (Ceph) should be able to do one at a time... treat it like a ceph OSD failure and flatten the node entirely / bring it back in.

[carpenike]

... but take a backup first. :-D

[onedr0p]

Yea, master is the hard one :)
I will probably wait until I can get my app data properly backed up and a way to restored before I do the rest. I can tear it all down and stand it back up.

[onedr0p]

Implementing this on my iteration of my cluster

[onedr0p]

Done