Sun Microsystems manual Ug Characteristics of Solaris 10 Zones

Version 3.1-enSolaris 10 Container Guide - 3.1 2. Functionality Effective: 30/11/2009

Thus, a local zone is a Solaris environment that is separated from other zones and can be used independently. At the same time, many hardware and operating system resources are shared with other local zones, which causes little additional runtime expenditure.

Local zones execute the same Solaris version as the global zone. Alternatively, virtual execution environments for older Solaris versions (SPARC: Solaris 8 and 9) or other operating systems (x86: Linux) can also be installed in so-called Branded Zones. In this case, the original environment is then executed on the Solaris 10 kernel; differences in the systemcalls are emulated.

Additional details are summarized in the following table:

Shared kernel:	The kernel is shared by the global zone and the local zones. The resources needed by the OS are
	needed only once. Costs for a local zone are therefore low, as measured by main memory, CPU
	consumption and disk space.
Shared objects:	In Unix, all objects such as programs, files and shared libraries are loaded only once as a shared
	memory segment which improves overall performance. For Solaris 10, this also includes zones; that is,
	no matter how frequently e.g. a program or a shared library is used in zones: in the main memory, it will
	occupy space only once. (other than in virtual machines.)
File system:	The visible portion of the file system of the local zone can be limited to one subtree or several subtrees of
	the global zone. The files in the local zone can be configured on the basis of directories shared with the
	global zone or as copies.
Patches:	For packages (Solaris packages) installed as copies in the local zone, patches can be installed
	separately as well. The patch level regarding non-Application patches should be the same, because all
	zones share the same kernel.
Network:	Zones have their own IP addresses on one or more virtual or physical interfaces. Network
	communication between zones takes place, if possible, via the shared network layers or when using
	exclusive IP-instances via external network connections.
Process:	Each local zone can see its own processes only. The global zone sees all processes of the local zones.
Separation:	Access to the resources of the global zone or other local zones, unless explicitly configured as such
	(devices, memory), is prevented. Any software errors that may occur are limited to their respective local
	zone by means of error isolation.
Assigned devices:	No physical devices are contained in the standard configuration of a local zone. It is, however, possible to
	assign devices (e.g. disks, volumes, DVD drives, etc.) to one or more local zones.
	Special drivers can be used this way as well.
Shared disk space:	In addition, further parts of the file tree (file systems or directories) can be assigned from the global zone
	to one or more local zones.
Physical devices:	Physical devices are administered from the global zone. Local zones do not have any access to the
	assignment of these devices.
Root delegation:	A local zone has an individual root account (zone administrator). Therefore, the administration of
	applications and services in a local zone can be delegated completely to other persons – including the
	root portion. Operating safety in the global zone or in other local zones is not affected by this. The global
	zone root has general access to all local zones.
Naming	Local zones have an independent naming environment with host names, network services, users, roles
environment:	and process environments. The name service of one zone can be configured from local files, and another
	zone from the same computer can use e.g. LDAP or NIS.
System settings:	Settings in /etc/system apply to the kernel used by all zones. However, the most important settings of
	earlier Solaris versions (shared memory, semaphores and message queues) can be modified from
	Solaris 10 onwards by the Solaris resource manager for each zone independently.

Table 1: [ug] Characteristics of Solaris 10 Zones

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