Overview of Solaris Zones

The Solaris 10 zones (also known as Solaris containers) feature provides a means of creating virtualized operating system environments within an instance of Solaris OS. This allows one or more processes to run in isolation from other activities on the host. For example, a process running in a zone will only be able to send signals to other processes in the same zone, regardless of user ID and other credential information.

Every Solaris 10 host contains a single global zone. The global zone is both the default zone for the host and the zone used for system-wide administrative control. All processes run in the global zone if no non-global zones are created by the global administrator. Some product components, such as Sun Cluster software can only be installed in the global zone. A non-global zone can be thought of as a box. One or more applications can run in this box without interacting with the rest of the host. Each non-global zone has what appears to be its own instance of an installed Solaris 10 operating system with configuration and other information unique to that non-global zone. The default configuration for a non-global zone is to share portions of its file system with the global zone. Propagation provides non-global visibility and availability to packages that are installed in the global zone.

There are two types of non-global zones supported: whole root zone and sparse root zone. A whole root zone contains a read/write copy of the file system that exists in the global zone. When a whole root non-global zone is created, all packages that are installed on the global zone are made available to the whole root zone. A package database is created and all packages are copied onto the non-global zone, creating a dedicated and independent copy of all files.

A sparse root zone contains a read/write copy of only a portion of the file system existing on the global zone, while other file systems are mounted read-only from the global zone as loopback virtual file systems. The global administrator selects which file systems to share with a sparse root zone at the time the sparse root zone is created. Regardless of zone type, when a package is added to the global zone it is, by default, propagated to all non-global zones. In other words, the package is installed in the global zone as well as all non-global zones. This propagation behavior can optionally be suppressed when the package is added, thus restricting the package to the global zone only.

For your zones deployment to succeed, it is crucial that you plan the tasks and sequence of those tasks very carefully. Communications Suite components can potentially be installed in any of three types of zones in an almost unlimited set of combinations, and in almost any order. In some cases, the order in which Communications Suite product components are installed, and the order in which non-local zones are created, can be very important. For a full description of planning for using Communications Suite in a Solaris zones environment, refer to the Sun Java Enterprise System 5 Installation Planning Guide.