KVM/QEMU Base/Template Images and the power they provide

 qemu-img create -b centos.5-8.x86.20120308.qcow2 -f qcow2 ../kvmguests/25000-centos5.8x86.qcow2
Formatting '../kvmguests/25000-centos5.8x86.qcow2', fmt=qcow2, backing_file=centos.5-8.x86.20120308.qcow2, size=10485760 kB

-b the source/base image

-f format is qcow2 and the location of the destination image

What is so special about this?  It's even quicker than creating a template with OpenVZ but this is an actual OS.

It saves time and disk space because it only writes the changes to the file of your image since the base OS/image is being used as a backing.  This means you could quickly and in an automated fashion create several servers for testing purposes for your applications or stress testing etc..

But there is one caveat and it's that you can't afford to lose the base image, it can't move or be modified/harmed otherwise the resulting images creating from it will stop working or have issues.  So it does introduce an unwanted and single point of failure, this is fine for testing but probably not wise to do for mission critical situations.


Tags:

kvm, qemu, template, images, img, centos, qcow, kvmguests, formatting, fmt, backing_file, kb, format, destination, quicker, creating, openvz, os, saves, disk, writes, backing, automated, servers, purposes, applications, etc, caveat, modified, harmed, resulting, unwanted,

Latest Articles

  • Centos 7 how to save iptables rules like Centos 6
  • nfs tuning maximum amount of connections
  • qemu-kvm error "Could not initialize SDL(No available video device) - exiting"
  • Centos 7 tftpd will not work with selinux enabled
  • Debian Ubuntu Mint Howto Create Bridge (br0)
  • How To Control Interface that dhcpd server listens to on Debian based Linux like Mint and Ubuntu
  • LUKS unable to type password to unlock during boot on Debian, Ubuntu and Mint
  • Debian Ubuntu and Linux Mint Broken Kernel After Date - New Extra Module Naming Convention
  • Wordpress overwrites and wipes out custom htaccess rules and changes soluton
  • Apache htaccess and mod_rewrite how to redirect and force all URLs and visitors to the SSL / HTTPS version
  • python 3 pip cannot install mysql module
  • QEMU-KVM won't boot Windows 2016 or 2019 server on an Intel Core i3
  • Virtualbox vbox not starting
  • Bind / named not responding to queries solution
  • Linux Mint How To Set Desktop Background Image From Bash Prompt CLI
  • ImageMagick Convert PDF Not Authorized
  • ImageMagick Converted PDF to JPEG some files have a black background solution
  • Linux Mint Mate Customize the Lock screen messages and hide username and real name
  • Ubuntu/Gnome/Mint/Centos How To Take a partial screenshot
  • ssh how to verify your host key / avoid MIM attacks