Sun Microsystems 10 Computer Hardware User Manual


 
Version 3.1-en Solaris 10 Container Guide - 3.1 2. Functionality Effective: 30/11/2009
2. Functionality
2.1. Solaris Containers and Solaris Zones
2.1.1. Overview
[ug] Solaris Zones is the term for a virtualized execution environment a virtualization at the operating
system level (in contrast to HW virtualization).
Solaris Containers are Solaris Zones with Resource Management. The term is frequently used
(in this document as well) as a synonym for Solaris Zones.
Resource Management has already been introduced with Solaris 9 and allows the definition of CPU,
main memory and network resources.
Solaris Zones represent a virtualization at the interface between the operating system and the
application.
There is a global zone which is essentially the same as a Solaris operating system was in earlier
versions
In addition, local zones, also called nonglobal zones, can be defined as virtual execution
environments.
All local zones use the kernel of the global zone and are thus part of a single physical operating
system installation unlike HW virtualization, where several operating systems are started on
virtualized hardware instances.
All shared objects (programs, libraries, the kernel) are loaded only once; therefore, unlike for
HW virtualization, additional consumption of main memory is very low.
The file system of a local zone is separated from the global zone. It uses a subdirectory of the
global zone's filesystem for a root directory (as in chroot environments).
A zone can have one or several network addresses and network interfaces of its own.
Physical devices are not visible in local zones (standard) but can optionally be configured.
Local zones have their own OS settings, e.g. for name service.
Local zones are separated from each other and from the global zone with respect to processes,
that is, a local zone cannot see the processes of a different zone.
The separation extends also to the shared memory segments and logical or physical network
interfaces.
Access to another local zone on the same computer is therefore possible through the network
only.
The global zone, however, can see all processes in the local zones for the purpose of control
and monitoring (accounting).
Figure 1: [dd] Schematic representation of zones
2
Server
OS
App
Local
zone
Local
zone
Local
zone
Global zone