typhoon/docs/architecture/operating-systems.md

Operating Systems

Typhoon supports Container Linux and Fedora Atomic 28 (deprecated). These two operating systems were chosen because they offer:

• Minimalism and focus on clustered operation
• Automated and atomic operating system upgrades
• Declarative and immutable configuration
• Optimization for containerized applications

Together, they diversify Typhoon to support a range of container technologies.

• Container Linux: Gentoo core, rkt-fly, docker
• Fedora Atomic: RHEL core, rpm-ostree, system containers (i.e. runc), CRI-O (future)

Host Properties

Property	Container Linux / Flatcar Linux	Fedora Atomic
host spec (bare-metal)	Container Linux Config	kickstart, cloud-init
host spec (cloud)	Container Linux Config	cloud-init
container runtime	docker	docker (CRIO planned)
cgroup driver	cgroupfs (except Flatcar edge)	systemd
logging driver	json-file	journald
storage driver	overlay2	overlay2

Kubernetes Properties

Property	Container Linux	Fedora Atomic
single-master	all platforms	all platforms
multi-master	all platforms	all platforms
control plane	self-hosted	self-hosted
kubelet image	upstream hyperkube	upstream hyperkube via system container
control plane images	upstream hyperkube	upstream hyperkube
on-host etcd	rkt-fly	system container (runc)
on-host kubelet	rkt-fly	system container (runc)
CNI plugins	calico or flannel	calico or flannel
coordinated drain & OS update	CLUO addon	manual (planned)

Directory Locations

Typhoon conventional directories.

Kubelet setting	Host location
cni-conf-dir	/etc/kubernetes/cni/net.d
pod-manifest-path	/etc/kubernetes/manifests
volume-plugin-dir	/var/lib/kubelet/volumeplugins

Kubelet Mounts

Container Linux

Mount location	Host location	Options
/etc/kubernetes	/etc/kubernetes	ro
/etc/ssl/certs	/etc/ssl/certs	ro
/usr/share/ca-certificates	/usr/share/ca-certificates	ro
/var/lib/kubelet	/var/lib/kubelet	recursive
/var/lib/docker	/var/lib/docker
/var/lib/cni	/var/lib/cni
/var/lib/calico	/var/lib/calico
/var/log	/var/log
/etc/os-release	/usr/lib/os-release	ro
/run	/run
/lib/modules	/lib/modules	ro
/etc/resolv.conf	/etc/resolv.conf
/opt/cni/bin	/opt/cni/bin

Fedora Atomic

Mount location	Host location	Options
/rootfs	/	ro
/etc/kubernetes	/etc/kubernetes	ro
/etc/ssl/certs	/etc/ssl/certs	ro
/etc/pki/tls/certs	/usr/share/ca-certificates	ro
/var/lib	/var/lib
/var/lib/kubelet	/var/lib/kubelet	recursive
/var/log	/var/log	ro
/etc/os-release	/etc/os-release	ro
/var/run/secrets	/var/run/secrets
/run	/run
/lib/modules	/lib/modules	ro
/etc/hosts	/etc/hosts	ro
/etc/resolv.conf	/etc/resolv.conf	ro
/opt/cni/bin	/opt/cni/bin (changing in future)