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vSphere Web Access 503 Service Unavailable Error And Solution

By default vSphere does not provide client for Linux or OS X. You need to use Windows system to manage your VMware ESX server. However, it does provides vSphere Web Access which allows you to organize and share virtual machines using web browser. If you try to access vSphere Web Access you may get an error which read as follows:

503 Service Unavailable

You can fix this problem as follows.
[click to continue…]

Virtualization: Run Windows and Linux at One Place

I've used VMWARE ESX / Xen paravirtualization, Virtuozzo, Solaris Containers, and FreeBSD Jails as os level virtualization. Virutalbox is another full virtualization solution. Presently, VirtualBox runs on Windows, Linux and Macintosh hosts and supports a large number of guest operating systems including but not limited to Windows (NT 4.0, 2000, XP, Server 2003, Vista), DOS/Windows 3.x, Linux (2.4 and 2.6), and OpenBSD.

Virtualization: Run Windows and Linux at One Place

Rakesh has published a small article about VirtualBox Virtualization software. Both Windows and Linux can be run together simultaneously, and you don't even need to switch between the two. With the seamless Windows feature of the latest version of VirtualBox virtualization software, you can seamlesssly run both Windows and Linux applications from the same desktop interface. This has been made possible by the combined efforts of VirtualBox and SeamlessRDP that is meant for seamless Windows support for rdesktop.

=> How to run Windows and Linux at one place? [ciol.com]

How to: Install and Setup XEN Virtualization Software on CentOS Linux 5

One of our regular reader asks:

I'm using CentOS Linux 5 server. How do I set up Xen on Linux ? How do I install guest VPS oses such as Fedora or Windows 2000 or Debian Linux inside XEN?

Xen is a free open source software virtual machine monitor for Intel / PowerPC architectures. It is software that runs on a host operating system and allows several guest operating systems to be run on top of the host on the same computer hardware at the same time (just like VMWare software). Luckily Installing and managing XEN is quite easy under CentOS 5 Linux.

Login as the root and type the following commands:
# yum install xen virt-manager kernel-xen
# chkconfig xend on
# reboot

Make sure you boot CentOS server using XEN kernel.

How do I install NetBSD / any Linux distro / Windows 2000 inside XEN?

Simply use gui tool called virt-manager:
# virt-manager &

CentOS XEN Virtual machine manager

CentOS XEN Virtual machine manager

Now just follow on screen instructions to setup new guest operating systems (VPS oses). virt-manager is Xen Management Consoles software. It can perform the common tasks of administering a Xen host such as configuring, starting, monitoring and stopping of Xen guests oses. Please note that above instructions also works on

  • RHEL 5
  • Fedora Linux 7

Installing CentOS 5.3 guest using the Internet

virt-install is a command line tool for provisioning new virtual machines using the "libvirt" hypervisor management library. Type the following command to install CentOS v5.3 64 bit as guest operating system in /vm:
# mkdir /vm
If you are using SELinux, enter:
# semanage fcontext -a -t xen_image_t "/vm(/.*)?"
# restorecon -R /vm
# ls -dZ /vm

Above will provide security context of Xen images. Finally, install CentOS 5.3 using the Internet mirror:
# virt-install \
--paravirt \
--name webserver01 \
--ram 512 \
--file /vm/webserver.nixcraft.com.img \
--file-size 10 \
--nographics \
--location http://mirrors.kernel.org/centos/5.3/os/x86_64/

Above will CentOS as a paravirtualized Xen guest, with 512 MB of RAM, a 10 GB of disk, and from a web server, in text-only mode. You need to just follow on screen instructions.

Fig.01: Centos Xen Virtualization Installation

Fig.01: Centos Xen Virtualization Installation

Once installed you can use xm command to list, start, stop and manage xen vps:
# xen list
Attach console to domain / guest called webserver01:
# xm console webserver01
See xm command cheat sheet.

Installing CentOS 5.3 guest using DVD

Install a CentOS guest, using LVM partition, virtual networking, booting from the host CDROM, using VNC server/viewer (insert DVD into drive):
# virt-install \
--connect qemu:///system \
--name mailserver
--ram 500 \
--file /dev/HostVG/mailserver.cyberciti.biz \
--network network:default \
--accelerate \
--vnc \
--cdrom /dev/cdrom

Note you need qemu and virt-viewer installed on the host system.

Installing Fedora guest using DVD iso image stored on hard disk

Install a Fedora Linux, with a real partition (/dev/sdc), using a local DVD ISO image:
# virt-install \
--name www2 \
--ram 1000 \
--file /dev/sdc \
--network bridge:eth1 \
--cdrom /tmp/fedorabootdvd.iso

Further readings: