23-07-2012, 02:24 PM
Virtualization Guide Red Hat Virtualization
Virtualization.pdf (Size: 1.33 MB / Downloads: 41)
A functional Red Hat Virtualization system is multi-layered and is driven by the privileged Red
Hat Virtualization component. Red Hat Virtualization can host multiple guest operating systems.
Each guest operating system runs in its own domain, Red Hat Virtualization schedules virtual
CPUs within the virtual machines to make the best use of the available physical CPUs. Each
guest operating systems handles its own applications. These guest operating systems schedule
each application accordingly.
You can deploy Red Hat Virtualization in one of two choices: full virtualization or paravirtualization.
Full virtualization provides total abstraction of the underlying physical system and creates
a new virtual system in which the guest operating systems can run. No modifications are
needed in the guest OS or application (the guest OS or application is not aware of the virtualized
environment and runs normally). Paravirualization requires user modification of the guest
operating systems that run on the virtual machines (these guest operating systems are aware
that they are running on a virtual machine) and provide near-native performance. You can deploy
both paravirtualization and full virtualization across your virtualization infrastructure.
Operating System Support
Red Hat Virtualization's paravirtualization mode allows you to utilize high performance virtualization
on architectures that are potentially difficult to virtualize such as x86 based systems. To deploy
para-virtualization across your operating system(s), you need access to the paravirtual
guest kernels that are available from a respective Red Hat distro (for example, RHEL 4.0, RHEL
5.0, etc.). Whilst your operating system kernels must support Red Hat Virtualization, it is not necessary
to modify user applications or libraries.
Red Hat Virtualization allows you to run an unmodified guest kernel if you have Intel VT and
AMD SVM CPU hardware. You do not have to port your operating system to deploy this architecture
on your Intel VT or AMD SVM systems. Red Hat Virtualization supports:
• Intel VT-x or AMD-V Pacifica and Vanderpool technology for full and paravirtualization.
• Intel VT-i for ia64
• Linux and UNIX operating systems, including NetBSD, FreeBSD, and Solaris.
• Microsoft Windows as an unmodified guest operating system with Intel Vanderpool or AMD's
Pacifica technology.
Hardware Support
Red Hat Virtualization supports multiprocessor systems and allows you can run Red Hat Virtualization
on x86 architectured systems with a P6 class (or earlier) processors like:
• Celeron
• Pentium II
• Pentium III
• Pentium IV
• Xeon
• AMD Athlon
• AMD Duron
With Red Hat Virtualization, 32-bit hosts runs only 32-bit paravirtual guests. 64-bit hosts runs
only 64-bit paravirtual guests. And a 64-bit full virtualization host runs 32-bit, 32-bit PAE, or
64-bit guests. A 32-bit full virtualization host runs both PAE and non-PAE full virtualization
guests.
Booting the System
After installing the Red Hat Virtualization components, you must reboot the system. When the
boot completes, you must log into your system as usual. Then before you start Red Hat Virtualization
you must log in a root. The xend control daemon should already be initiated by
initscripts, but to start the xend manually, enter:
service xend start
You can also use chkconfig xend when installing to enable xend at boot time.
The xend node control daemon performs system management functions that relate to virtual
machines. This daemon controls the virtualized resources, and xend must be running to interact
with virtual machines. Before you start xend, you must specify the operating parameters by editing
the xend configuration file xend-config.sxp which is located in the etc/xen directory.