rkt is an open source container runtime designed for composability, security, and speed.
CoreOS provide a software that securely run application containers anywhere.
Quay Enterprise is delivered as a set of containers that can run on any infrastructure. It is recommended to run Quay Enterprise in highly-available fashion, on multiple machines.
Tectonic ships with CoreOS's signature Automated Operations, enables portability across private and public cloud providers, and is always upstream open source.
etcd is a distributed key value store that provides a reliable way to store data across a cluster of machines.etcd gracefully handles leader elections during network partitions and will tolerate machine failure, including the leader.
flannel is a virtual network that gives a subnet to each host for use with container runtimes.
fleet is a cluster manager that controls systemd at the cluster level.