At First Customer Ship of Solaris 10, a technology known as Non-Global Zones (NGZ) / Containers were introduced into the Sun Microsystems realm. Given Oracle Corporations acquisition of Sun Microsystems, they became the “parent” of this technology as it relates to Solaris.
The technology allowed one to configure a “jail-cell” type environment where the root file system of the NGZ was chrooted in a fashion that prevented it access to the root file system of the Global Zone. The Global Zone was created when Solaris was installed.
This Technology is now being addressed/added to Linux Operating Systems.
NGZ’s provided a single OS instance to present as multiple instances. Each had a separate file system, separate root account, separate port ranges, separate IP addresses, separate process table, etc. From the outside looking in, they were separate systems. We were only managing a single kernel, so it is different from the Xen/KVM types of virtualization.
The in’s/out’s/why’s/why not’s of this technology is beyond what I want to share with this post. The information is freely available at Oracle’s web site and through Oracle University’s training.
Oracle’s Unbreakable Enterprise Kernel Release 2 (2.6.39) is supported for both Oracle Linux 5 and 6. This makes it possible to run Oracle Linux 5 and 6 container instances on top of an Oracle Linux 6 system. Since Linux Containers are fully implemented on the OS level (the Linux kernel), they can be easily combined with other virtualization technologies. It’s certainly possible to set up Linux containers within a virtualized Linux instance that runs inside Oracle VM Server or Oracle VM Virtualbox.
Note: Linux Containers on Oracle Linux 6 with the Unbreakable Enterprise Kernel Release 2 (2.6.39) are still marked as Technology Preview – their use is only recommended for testing and evaluation purposes
Additional links related to Linux Containers:
OTN Article: The Role of Oracle Solaris Zones and Linux Containers in a Virtualization Strategy
Linux Containers on Wikipedia
OTN Garage: Linux-Containers — Part 1: Overview