Introduction to Virtualization - Oracle Solaris 10 System Virtualization Essentials - page 40

tively, each VE may include some of the services provided by the operating system,
such as network services and naming services.
1.2.3.5 Flexibility and Granularity of Resource Configuration
Because one control point exists for all of the hardware and the VEs, all resource
management decisions can be made from one central location. For example, the
single process scheduler can be modified to provide new features for the system
administrator. These features can be used to ensure that the desired amount of
compute power is applied to each VE to meet business needs. Because the sched-
uler can monitor each process in each VE, it can make well-informed scheduling
decisions; it does not need to give control to a separate scheduler per VE.
An alternative method to moderate CPU power as a resource gives one VE ex-
clusive access to a set of CPUs. This approach means that the VE's processes have
access to all of the CPU capacity of these CPUs and reduces cache contention.
RAM can be treated similarly, either as an assignment of a physical address range
or as a simple quantity of memory.
Other resource constraints can include limits or guaranteed minimum amounts
or portions.
1.2.3.6 Scalability
Operating system virtualization technologies tend to scale as well as the underly-
ing operating system. From one perspective, all processes in all VEs can be seen as
a set of processes managed by one kernel, including inter-VE isolation rules. If the
kernel scales well to many processes, the system should scale well to many VEs of
this type. At least one implementation of OS virtualization—Solaris Containers—
has demonstrated excellent scalability, with more than 100 running VEs on one
Solaris instance.
1.2.3.7 Platform Management
Operating system features must provide the ability to create, configure, manage,
and destroy VEs. This capability can be extended to remote management.
1.2.3.8 Relative Strengths
Similar to other virtualization models, OSV has its particular strengths. Some of
these are specific goals of OSV implementations; others are side effects of the OSV
model.
Many of the strengths of OSV implementations are derived from the tight in-
tegration between the OSV technology and the OS kernel. Most of these operat-
ing systems are mature and have well-developed facilities to install and maintain
them and to manage multiple workloads. It is usually possible to extend those
features to the environments created via OSV.