typhoon/docs/architecture/operating-systems.md

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# Operating Systems
Typhoon supports [Container Linux](https://coreos.com/why/) and Fedora [Atomic](https://www.projectatomic.io/) 27. 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
## Kubernetes
| Property | Container Linux | Fedora Atomic |
|-------------------|-----------------|---------------|
| control plane | self-hosted | self-hosted |
| kubelet image | upstream hyperkube | upstream hyperkube in system container |
| controller images | upstream hyperkube | upstream hyperkube |
| on-host etcd | rkt-fly | system container (runc) |
| on-host kubelet | rkt-fly | system container (runc) |
| host spec (bare-metal) | Container Linux Config | kickstart, cloud-init |
| host spec (cloud) | Container Linux Config | cloud-init |
| CNI plugins | calico or flannel | calico or flannel |
| container runtime | docker | docker (CRIO soon) |
| cgroup driver | cgroupfs | systemd |
| logging driver | json-file | journald |
| storage driver | overlay2 | overlay2 |
## Locations
Typhoon standard locations.
| 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 | |