vSekar Blog

There are many differences between Windows 7, Windows Vista and Windows XP. There are many features of Windows 7 that are not enabled by default unlike Windows Vista. This article attempts to address this issue and offer info to help users get the most from Windows 7.

A feature of Windows 7 that maybe missed by a user if not turned on is the Aero Glass Transparency effect. This offers interface effects like the translucent glass design and other visual experiences. It can be enabled by following these steps:

First check that the Windows Experience Index has been computed and calculated.

Next type Aero into the Start Search box, then click on find and fix problem with transparency and other visual effects. If it doesn’t show up try looking in the control panel for items regarding Aero. Lastly click ‘next’ on the Aero wizard dialogue box that will appear.

Another useful tip is knowing how to open Problem Steps Recorder. To do so go to the troubleshooting area in the control panel and launch it or search for psr.exe in the start menu.

Another useful tip is to know that a user can dual boot Windows 7, so they can keep their Windows XP or Vista set up or you can use it by setting up a virtual version. It can be set up in about 20 minutes using VMware Workstation.

Here’s a trick for users wishing to change the size of desktop icons. This is done by pressing once on the icon and then holding down the Ctrl Key, after which use your mouse’s scroll wheel to adjust the size of the icon, click into the desktop and refresh.

If you have problems starting up because the bootmanager of Windows is damaged. Start up using the dvd you used to install the software and then after you see the License Agreement choose the ‘repair’ option.

These are just some of the useful nuggets of info that can help you when finding your feet with a new version of sotware. I hope you have found them useful.

Source by Simon Surfer

Introduction to KVM

Kernel-based Virtual Machine (KVM) is a virtualization infrastructure for the Linux kernel. KVM supports native virtualization (where we can simulate a complete hardware environment on which we can run unmodified guest operating system) on processors with hardware virtualization extensions (Intel VT or AMD-V). It consists of a loadable kernel module, kvm.ko, that provides the core virtualization infrastructure and a processor specific module, kvm-intel.ko or kvm-amd.ko. The kernel component of KVM is included in mainline Linux, as of 2.6.20. KVM is an opensource software, KVM’s parts are licensed under various GNU licenses.

In the KVM architecture the virtual machine is implemented as regular Linux process. This allows KVM to benefit from all the features of the Linux kernel. Device emulation is handled by a modified version of QEMU. Since KVM is a part of Linux any hardware device supported by Linux can be used by KVM.

libvirt is an open source API, daemon and management tool for managing platform virtualization. It can be used to manage Linux KVM, Xen, VMware ESX, qemu and other virtualization technologies. Libvirt is used by various virtualization programs/softwares/platforms. Graphical Interfaces are provided by Virtual Machine Manager and others. The most popular command line interface is (virsh), and higher level tools like oVirt.

Implementing KVM with CentOS

1. Checking the processor compatibility.

For Intel Processors grep vmx /proc/cpuinfo –color

For AMD processors grep svm /proc/cpuinfo –color

If we get any output for the above commands that indicate our processor is compatible for KVM.

Sample output for Intel(R) Core(TM)2 Duo CPU E8500 @ 3.16GHz is given below

flags: fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 xsave lahf_lm dts tpr_shadow vnmi flexpriority

flags: fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 xsave lahf_lm dts tpr_shadow vnmi flexpriority

2. Installing and running KVM Packages

yum install kvm libvirt virt-manager bridge-utils

service libvirtd restart

Package Description(As given by ‘yum info’)

kvm: A full virtualization solution for Linux on x86 hardware.

libvirt: A C toolkit to interact with the virtualization capabilities of recent versions of Linux (and other OSes).

virt-manager: Virtual Machine Manager provides a graphical tool for administering virtual machines for KVM, Xen, and Qemu.

bridge-utils: This package contains utilities for configuring the linux ethernet bridge. The linux ethernet bridge can be used for connecting multiple ethernet devices together.

From this point we can use tools like virsh or virt-manager to manage your virtual machine.

3. Configuring Ethernet Bridge

NetworkManager service need to be stopped while working with bridge.

service NetworkManager stop

chkconfig NetworkManager off

Create a file /etc/sysconfig/network-scripts/ifcfg-br*

DEVICE=br*

ONBOOT=yes

TYPE=Bridge

BOOTPROTO=none

IPADDR=<IP_Address>

NETMASK=<Subnet_Mask>

GATEWAY=<Default_Gateway>

Edit the interface files(/etc/sysconfig/network-scripts/ifcfg-eth*) as given below

DEVICE=eth*

ONBOOT=yes

BRIDGE=br0

TYPE=Ethernet

Restart the network service

service network restart

We can manage the VMs with the graphical tool virt-manager (Virtual Machine Manager) or command line tools like virsh or virt install. For more information about the options available with it you can see the man pages. These commandline tools are very useful in creating scripts for managing Vms.

We can create a virtual machine and start PXE installation by running the command given below.

virt-install –vnc –name=server6 –ram=1024 –arch=x86_64 –vcpus=1 –os-type=linux -os-variant=rhel6 –disk=/var/lib/libvirt/images/server6.img -w bridge=br0 –mac=54:52:00:00:00:06 –pxe

Source by Krishnadas Thengil

(Or How to set up a fully working Joomla, Drupal, LAMP, LAPP, Zimbra, Torrent server etc., in a couple of minutes)

Turnkey Linux comprises a set of free, Ubuntu-based software appliances that are primarily available for server-type usage scenarios, such as setting up database, web, forum, wiki and photo gallery servers. Each appliance is preconfigured to work out of the box, with ease of use being the primary goal behind the Turnkey Linux project.

This is extremely useful in itself, but if you wanted to experiment with these appliances, potentially to evaluate or otherwise test them, it would be great if you could perform installations with the absolute minimum of effort.

Using Turnkey Linux on Virtual Private Servers

A number of hosting providers out there provide Linux VPS services, which usually enable users to have their own virtual server with automatic provisioning of major Linux distributions, such as Debian, Ubuntu or CentOS. Work has been performed in conjunction with the Turnkey Linux team and has managed to take the automatic installation concept one step further to enable this to work with all Turnkey Linux appliances. This is made possible by using frameworks provided by the excellent server open source control panel, DTC.

Turnkey Linux appliances enable users to easily deploy primarily web-based applications within an entire Linux kernel and Ubuntu-based package set. Once a distribution is chosen within the control panel, the install is fully completed within a few minutes and ready to be customised. This enables a rapid deployment of a tested setup, with full update and security support provided by the Turnkey Linux and Ubuntu package maintainers.

Our efforts are available to all using the DTC control panel, with Debian packages for Lenny being provided. Additionally, scripts have been written such that when new or updated appliances are released, new deployable packages for the DTC control panel are created and made available in our repository automatically.

Technical Script Details

It is not actually too difficult to configure images to work for automatic deployment, but performing this manually for every appliance is a time consuming process. The scripts we have written will automatically perform the following steps for each appliance:

1. Create a new directory with a name similar to the actual release version, e.g. turnkey-core-2009.02-hardy-x86.
2. Copy across common template files. These include the following:
   • custom_os: Customises each appliance by configuring basic networking, spawning gettys on the right devices and setting a customised MOTD with the VPS number and hostname.
   • install_os: Custom instructions to install this appliance, which essentially involves untaring the provided image into the VPS.
   • setup_network: Custom instructions called when setting up the network. Because Turnkey Linux uses resolveconf for DNS configuration, this reads information from /etc/resolv.conf from the dom0 (this is designed for use with Xen) and copies it to /etc/network/interfaces in the domU.
   • debian/*: These are the files changelog, control, compat, copyright, files, install and rules which are required to create a.deb packages. These have substitution variables (e.g. for the package name) which are overwritten by our script.
3. Copy the preinstalled image (a.tar.bz2 file).
4. Tailor the template files (as above).
5. Invoke dpkg-buildpackage in this directory to create the actual.deb file.
6. Call reprepro, a tool we use to manage Debian repository directory structures, to remove old versions of this appliance and add the new one.

It’s as simple as that. If you are interested, the raw scripts are downloadable. They will need some customisation for your setup as there are hard coded directories in there.

I want to play with one!

If you are happy playing with just one appliance, you can of course just download it from the Turnkey Linux website and install it on your PC (or use a Virtualisation solution like Xen or VMWare).

However, if you want to rapidly try out a variety of appliances using the setup we have made, the quickest way would be to rent a VPS. Alternately, you can install the DTC control panel yourself and add our Debian repository to your /etc/apt/sources.list. This setup requires you to run a fully featured Xen setup and requires significant configuration.

Any questions?

Source by Marc Warne