Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Solaris Containers (including Solaris Zones) is an implementation of operating system-level virtualization technology first made available in 2005 as part of Solaris 10. A Solaris Container is the combination of system resource controls and the boundary separation provided by zones. Zones act as completely isolated virtual servers within a single operating system instance. By consolidating multiple sets of application services onto one system and by placing each into isolated virtual server containers, system administrators can reduce cost and provide all the same protections of separate machines on a single machine. There is always one zone defined, named the "global" zone. Zones hosted by a global zone are known as "non-global zones" but are sometimes just called "zones". The term "local zone" is specifically discouraged, since in this usage "local" is not an antonym of "global". The global zone encompasses all processes running on the system, whether or not these processes are running within a non-global zone. Unless otherwise noted, "zone" will refer to non-global zones in this article.