Startup guide for kvm on cent os 6


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Startup guide for kvm on cent os 6

  1. 1. Startup Guide for KVM on CentOS 6 « Techno Crazy Techno Crazy Simplifying Server Aidministration Home About Home > Uncategorized > Startup Guide for KVM on CentOS 6 Startup Guide for KVM on CentOS 6 August 29, 2011 balrawat Leave a comment Go to comments These instructions are very specific to CentOS 6. For this I assume you have setup your server using the “Minimal” option when installing CentOS 6. You must also have the Virtualization features enabled for your CPU. This is done in your host’s BIOS. Optionally you can skip the first section, Installing KVM, if you check all 4 “Virtualization” software categories during the install. Installing KVM If you choose the “Minimal” option during CentOS 6 then this step is necessary. To get the full set of tools there are 4 software groups to install… Virtualization Virtualization Client Virtualization Platform Virtualization Tools To install run yum groupinstall “Virtualization*” dejavu-lgc-sans-fonts is necessary or all the fonts in virt-manager will show as squares yum install dejavu-lgc-sans-fonts Once the install is finished verify that the KVM kernel module is loaded. lsmod | grep kvm You should see either kvm_intel or kvm_amd depending on your host’s CPU manufacturer. At this point I chose to reboot the server. This allows services to be started and udev rules for KVM to be applied. This will also allow dbus to create the machine-id file, otherwise you would see something like the below when running virt-manager # virt-manager Xlib: extension “RANDR” missing on display “localhost:10.0″. process 1869: D-Bus library appears to be incorrectly set up; failed to read machine uuid: Failed to open “/var/lib/dbus/machine-id”: No such file or directory See the manual page for dbus-uuidgen to correct this issue. D-Bus not built with -rdynamic so unable to print a backtrace1 de 5 17/11/2011 09:49
  2. 2. Startup Guide for KVM on CentOS 6 « Techno Crazy Aborted If you receive that D-Bus error and would prefer not to restart then run this command to generate the necessary machine-id file dbus-uuidgen > /var/lib/dbus/machine-id Final configuration steps The server I run KVM on is headless, but I still like using virt-manager. So we must install the necessary tools to do X11 forwarding through SSH. yum install xorg-x11-xauth # If you plan to use VNC to connect to the virtual machine’s console locally yum install tigervnc Now when you connect through SSH be sure to pass the -X flag to enable X11 forwarding. Optional: Using an alternate location for VM images with SELinux With SELinux enabled, special steps must be taken to change the default VM store from /var/lib/libvirt /images. My particular server I choose to keep all images and ISOs for VMs under /vmstore. The steps below give your new store the correct security context for SELinux. # this package is necessary to run semanage yum install policycoreutils-python semanage fcontext -a -t virt_image_t “/vmstore(/.*)?” restorecon -R /vmstore To activate this store you must open virt-manager, select your host, then do Edit-> Host Details. Under the Storage tab you can add your new storage volume. Optional : Network Bridging for Virtual Machines If you wish for your virtual machines to be accessible remotely then you must use network bridging to share your host’s network interface with the virtual machines. The setup requires linking one of your host’s physical interfaces with a bridge device. First copy your physical interface’s ifcfg file to create the new bridge device, named br0. cp /etc/sysconfig/networking-scripts/ifcfg-eth0 /etc/sysconfig/networking-scripts/ifcfg-br0 Modify ifcfg-br0 to have the IP information in ifcfg-eth0 and remove, or comment out, that information in ifcfg-eth0. Below are examples of ifcfg-eth0 and ifcfg-br0. The highlighted lines are important. /etc/sysconfig/networking-scripts/ifcfg-eth0 DEVICE=eth0 HWADDR=00:18:8B:58:07:3B ONBOOT=yes BRIDGE=br0 /etc/sysconfig/networking-scripts/ifcfg-br0 DEVICE=br0 TYPE=Bridge BOOTPROTO=static ONBOOT=yes IPADDR= NETMASK= Once those two files are configured restart the network service service network restart2 de 5 17/11/2011 09:49
  3. 3. Startup Guide for KVM on CentOS 6 « Techno Crazy Optional: Managing libvirt with standard user account Beginning in CentOS 6 access to managing libvirt is handled by [ /page/SSHPolicyKitSetup PolicyKit]. It’s always a good practice to do your daily administration tasks as some user besides root, and using PolicyKit you can give access to libvirt functions to a standard account. First we create the necessary config file to define the access controls. The file must begin with a numeric value and have the .pkla extension. vim /etc/polkit-1/localauthority/50-local.d/50-libvirt-remote-access.pkla Here’s an example of the file I used to give access to a single user. Be sure to put your desired username in place of username on the highlighted line. [libvirt Management Access] Identity=unix-user:username Action=org.libvirt.unix.manage ResultAny=yes ResultInactive=yes ResultActive=yes You can optionally replace Identity=unix-user:username with Identity=unix-group:groupname to allow access to a group of users. Finally restart the libvirtd daemon to apply your changes. /etc/init.d/libvirtd restart Creating the first virtual machine You are now ready to create your virtual machines. Create the virtual disk With the version of virt-manager shipped with CentOS 6 you cannot create qcow2 images from within the GUI. If you wish to create your new VM with a qcow2 format virtual disk you must do so from the command line, or see the next section for RPMs to upgrade virt-manager. qemu-img create -f qcow2 CentOS-6.0-x86_64-Template.qcow2 20G NOTE: Replace the filename “CentOS-6.0-x86_64-Template” with your desired name, and also replace “20G” with the desired max size of the virtual disk. Now when creating your virtual machine select to use an existing virtual disk. Share this:3 de 5 17/11/2011 09:49
  4. 4. Startup Guide for KVM on CentOS 6 « Techno Crazy Like this: Be the first to like this post. Categories: Uncategorized Comments (0) Trackbacks (0) Leave a comment Trackback 1. No comments yet. 1. No trackbacks yet. Leave a Reply Fill in your details below or click an icon to log in: Notify me of follow-up comments via email. Post Comment SQL Server point in time recovery Crazy Commands RSS feed Google Youdao Xian Guo Zhua Xia My Yahoo! newsgator Bloglines iNezha Calendar August 2011 M T W T F S S 1 2 3 4 5 6 7 8 9 10 11 12 13 14 « May Sep »4 de 5 17/11/2011 09:49
  5. 5. Startup Guide for KVM on CentOS 6 « Techno Crazy M T W T F S S 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 « May Sep » Archives September 2011 (1) August 2011 (1) May 2011 (1) April 2011 (1) March 2011 (4) Recent Posts SQL Server point in time recovery Startup Guide for KVM on CentOS 6 Crazy Commands How to install NTOP on CentOS 5.5 64bits How to Block the Amazon AWS EC2 crawlers Email Subscription Enter your email address to subscribe to this blog and receive notifications of new posts by email. Join 1 other follower Top WordPress Copyright © 2009-2011 Techno Crazy Blog at Theme: INove by NeoEase.5 de 5 17/11/2011 09:49