This chapter will cover the internals of CoreOS' critical services—Etcd, Systemd, and Fleet. For each of the services, we will cover installation, configuration, and their applications. CoreOS ships with Etcd, Systemd, and Fleet by default. They can also be installed as standalone components in any Linux system. The following topics will be covered in this chapter:
Etcd—installation, access methods, configuration options, use cases, tuning, cluster management, security, authentication, and debugging
Systemd—unit types, specifiers, templates, and special units
Fleet—installation, access methods, templates, scheduling, HA, and debugging
Service discovery options using Etcd and Fleet