Chapter 1, CoreOS, Yet Another Linux Distro covers CoreOS cluster architecture. We will summarize it here again. A CoreOS member or node can contain multiple Docker containers. There can be multiple CoreOS members forming a CoreOS cluster.
CoreOS uses fleet to schedule and manage the services using
systemd onto the CoreOS members during initialization. This is similar to the
systemd starting and managing service on Linux machines. The scope of the Linux
systemd process is limited to a host node, whereas CoreOS
fleetd is the init system for a complete CoreOS cluster.
CoreOS uses etcd for node discovery and storing key-value pairs of configuration items accessible across a cluster member.
It's possible to set up a cluster in two ...