Starting with 1.22, all KubeZero nodes will boot from custom pre-baked AMIs. These AMIs will be provided and shared by the Zero Down Time for all customers. All sources and the build pipeline are freely [available](https://git.zero-downtime.net/ZeroDownTime/alpine-zdt-images) as usual though.
This eliminates *ALL* dependencies at boot time other than container registries. Gone are the days when Ubuntu, SuSE or Github decided to ruin your morning coffee.
KubeZero also migrates from Ubuntu 20.04 LTS to [Alpine v3.15](https://www.alpinelinux.org/releases/) as its base OS, which reduces the root file system size from 8GB to 2GB.
Additionally all AMIs are encrypted, which is ensures encryption at rest even for every instance's root file system. This closes the last gaps in achieving *full encryption at rest* for every volume within a default KubeZero deployment.
The [external-dns](https://github.com/kubernetes-sigs/external-dns) controller got integrated and is used to provide DNS based loadbalacing for the apiserver itself. This allows high available control planes on AWS as well as bare-metal in combination with various DNS providers.
Further usage of this controller to automate any DNS related configurations, like Ingress etc. is planned for following releases.
Cri-o now uses crun rather than runc, which reduces the memory overhead *per pod* from 16M to 4M, details at [crun intro](https://www.redhat.com/sysadmin/introduction-crun)
- kubelet root moved to `/var/lib/containers` to ensure ephemeral storage is allocated from the configurable volume rather than the root fs of the worker