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<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook V4.2//EN" [ |
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]> |
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<article class="specification"> |
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<articleinfo> |
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<title>Ganeti installation tutorial</title> |
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</articleinfo> |
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<para>Documents Ganeti version 1.2</para> |
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|
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<sect1> |
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<title>Introduction</title> |
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|
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<para> |
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Ganeti is a cluster virtualization management system based on |
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Xen. This document explains how to bootstrap a Ganeti node (Xen |
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<literal>dom0</literal>), create a running cluster and install |
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virtual instance (Xen <literal>domU</literal>). You need to |
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repeat most of the steps in this document for every node you |
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want to install, but of course we recommend creating some |
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semi-automatic procedure if you plan to deploy Ganeti on a |
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medium/large scale. |
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</para> |
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|
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<para> |
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A basic Ganeti terminology glossary is provided in the |
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introductory section of the <emphasis>Ganeti administrator's |
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guide</emphasis>. Please refer to that document if you are |
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uncertain about the terms we are using. |
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</para> |
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|
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<para> |
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Ganeti has been developed for Linux and is |
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distribution-agnostic. This documentation will use Debian Etch |
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as an example system but the examples can easily be translated |
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to any other distribution. You are expected to be familiar with |
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your distribution, its package management system, and Xen before |
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trying to use Ganeti. |
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</para> |
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|
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<para>This document is divided into two main sections: |
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|
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<itemizedlist> |
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<listitem> |
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<simpara>Installation of the base system and base |
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components</simpara> |
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</listitem> |
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<listitem> |
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<simpara>Configuration of the environment for |
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Ganeti</simpara> |
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</listitem> |
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</itemizedlist> |
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|
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Each of these is divided into sub-sections. While a full Ganeti system |
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will need all of the steps specified, some are not strictly required for |
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every environment. Which ones they are, and why, is specified in the |
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corresponding sections. |
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</para> |
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|
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</sect1> |
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|
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<sect1> |
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<title>Installing the base system and base components</title> |
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|
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<sect2> |
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<title>Hardware requirements</title> |
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|
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<para> |
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Any system supported by your Linux distribution is fine. 64-bit |
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systems are better as they can support more memory. |
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</para> |
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|
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<para> |
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Any disk drive recognized by Linux |
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(<literal>IDE</literal>/<literal>SCSI</literal>/<literal>SATA</literal>/etc.) |
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is supported in Ganeti. Note that no shared storage (e.g. |
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<literal>SAN</literal>) is needed to get high-availability features. It |
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is highly recommended to use more than one disk drive to improve speed. |
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But Ganeti also works with one disk per machine. |
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</para> |
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|
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<sect2> |
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<title>Installing the base system</title> |
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|
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<para> |
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<emphasis role="strong">Mandatory</emphasis> on all nodes. |
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</para> |
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|
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<para> |
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It is advised to start with a clean, minimal install of the |
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operating system. The only requirement you need to be aware of |
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at this stage is to partition leaving enough space for a big |
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(<emphasis role="strong">minimum |
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<constant>20GiB</constant></emphasis>) LVM volume group which |
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will then host your instance filesystems. The volume group |
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name Ganeti 1.2 uses (by default) is |
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<emphasis>xenvg</emphasis>. |
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</para> |
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|
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<para> |
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While you can use an existing system, please note that the |
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Ganeti installation is intrusive in terms of changes to the |
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system configuration, and it's best to use a newly-installed |
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system without important data on it. |
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</para> |
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|
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<para> |
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Also, for best results, it's advised that the nodes have as |
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much as possible the same hardware and software |
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configuration. This will make administration much easier. |
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</para> |
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|
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<sect3> |
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<title>Hostname issues</title> |
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<para> |
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Note that Ganeti requires the hostnames of the systems |
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(i.e. what the <computeroutput>hostname</computeroutput> |
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command outputs to be a fully-qualified name, not a short |
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name. In other words, you should use |
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<literal>node1.example.com</literal> as a hostname and not |
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just <literal>node1</literal>. |
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</para> |
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|
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<formalpara> |
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<title>Debian</title> |
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<para> |
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Note that Debian Etch configures the hostname differently |
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than you need it for Ganeti. For example, this is what |
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Etch puts in <filename>/etc/hosts</filename> in certain |
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situations: |
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<screen> |
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127.0.0.1 localhost |
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127.0.1.1 node1.example.com node1 |
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</screen> |
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|
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but for Ganeti you need to have: |
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<screen> |
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127.0.0.1 localhost |
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192.168.1.1 node1.example.com node1 |
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</screen> |
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replacing <literal>192.168.1.1</literal> with your node's |
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address. Also, the file <filename>/etc/hostname</filename> |
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which configures the hostname of the system should contain |
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<literal>node1.example.com</literal> and not just |
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<literal>node1</literal> (you need to run the command |
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<computeroutput>/etc/init.d/hostname.sh |
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start</computeroutput> after changing the file). |
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</para> |
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</formalpara> |
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</sect3> |
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|
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</sect2> |
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|
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<sect2> |
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<title>Installing Xen</title> |
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|
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<para> |
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<emphasis role="strong">Mandatory</emphasis> on all nodes. |
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</para> |
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|
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<para> |
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While Ganeti is developed with the ability to modularly run on |
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different virtualization environments in mind the only one |
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currently useable on a live system is <ulink |
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url="http://xen.xensource.com/">Xen</ulink>. Supported |
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versions are: <simplelist type="inline"> |
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<member><literal>3.0.3</literal></member> |
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<member><literal>3.0.4</literal></member> |
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<member><literal>3.1</literal></member> </simplelist>. |
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</para> |
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|
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<para> |
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Please follow your distribution's recommended way to install |
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and set up Xen, or install Xen from the upstream source, if |
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you wish, following their manual. |
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</para> |
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|
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<para> |
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After installing Xen you need to reboot into your Xen-ified |
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dom0 system. On some distributions this might involve |
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configuring GRUB appropriately, whereas others will configure |
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it automatically when you install Xen from a package. |
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</para> |
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|
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<formalpara><title>Debian</title> |
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<para> |
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Under Debian Etch or Sarge+backports you can install the |
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relevant <literal>xen-linux-system</literal> package, which |
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will pull in both the hypervisor and the relevant |
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kernel. Also, if you are installing a 32-bit Etch, you should |
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install the <computeroutput>libc6-xen</computeroutput> package |
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(run <computeroutput>apt-get install |
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libc6-xen</computeroutput>). |
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</para> |
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</formalpara> |
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|
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<sect3> |
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<title>Xen settings</title> |
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|
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<para> |
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It's recommended that dom0 is restricted to a low amount of |
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memory (<constant>512MiB</constant> is reasonable) and that |
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memory ballooning is disabled in the file |
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<filename>/etc/xen/xend-config.sxp</filename> by setting the |
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value <literal>dom0-min-mem</literal> to |
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<constant>0</constant>, like this: |
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<computeroutput>(dom0-min-mem 0)</computeroutput> |
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</para> |
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|
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<para> |
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For optimum performance when running both CPU and I/O |
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intensive instances, it's also recommended that the dom0 is |
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restricted to one CPU only, for example by booting with the |
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kernel parameter <literal>nosmp</literal>. |
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</para> |
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|
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<para> |
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It is recommended that you disable xen's automatic save of virtual |
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machines at system shutdown and subsequent restore of them at reboot. |
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To obtain this make sure the variable |
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<literal>XENDOMAINS_SAVE</literal> in the file |
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<literal>/etc/default/xendomains</literal> is set to an empty value. |
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</para> |
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|
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<formalpara> |
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<title>Debian</title> |
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<para> |
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Besides the ballooning change which you need to set in |
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<filename>/etc/xen/xend-config.sxp</filename>, you need to |
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set the memory and nosmp parameters in the file |
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<filename>/boot/grub/menu.lst</filename>. You need to |
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modify the variable <literal>xenhopt</literal> to add |
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<userinput>dom0_mem=512M</userinput> like this: |
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<screen> |
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## Xen hypervisor options to use with the default Xen boot option |
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# xenhopt=dom0_mem=512M |
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</screen> |
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and the <literal>xenkopt</literal> needs to include the |
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<userinput>nosmp</userinput> option like this: |
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<screen> |
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## Xen Linux kernel options to use with the default Xen boot option |
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# xenkopt=nosmp |
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</screen> |
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|
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Any existing parameters can be left in place: it's ok to |
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have <computeroutput>xenkopt=console=tty0 |
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nosmp</computeroutput>, for example. After modifying the |
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files, you need to run: |
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<screen> |
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/sbin/update-grub |
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</screen> |
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</para> |
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</formalpara> |
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<para> |
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If you want to test the HVM support |
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with Ganeti and want VNC access to the console of your |
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instances, set the following two entries in |
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<filename>/etc/xen/xend-config.sxp</filename>: |
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<screen> |
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(vnc-listen '0.0.0.0') |
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(vncpasswd '') |
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</screen> |
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You need to restart the Xen daemon for these settings to |
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take effect: |
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<screen> |
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/etc/init.d/xend restart |
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</screen> |
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</para> |
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|
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</sect3> |
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|
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<sect3> |
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<title>Selecting the instance kernel</title> |
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|
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<para> |
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After you have installed Xen, you need to tell Ganeti |
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exactly what kernel to use for the instances it will |
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create. This is done by creating a |
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<emphasis>symlink</emphasis> from your actual kernel to |
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<filename>/boot/vmlinuz-2.6-xenU</filename>, and one from |
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your initrd to |
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<filename>/boot/initrd-2.6-xenU</filename>. Note that if you |
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don't use an initrd for the <literal>domU</literal> kernel, |
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you don't need to create the initrd symlink. |
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</para> |
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|
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<formalpara> |
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<title>Debian</title> |
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<para> |
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After installation of the |
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<literal>xen-linux-system</literal> package, you need to |
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run (replace the exact version number with the one you |
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have): |
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<screen> |
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cd /boot |
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ln -s vmlinuz-2.6.18-5-xen-686 vmlinuz-2.6-xenU |
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ln -s initrd.img-2.6.18-5-xen-686 initrd-2.6-xenU |
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</screen> |
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</para> |
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</formalpara> |
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</sect3> |
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|
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</sect2> |
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|
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<sect2> |
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<title>Installing DRBD</title> |
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|
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<para> |
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Recommended on all nodes: <ulink |
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url="http://www.drbd.org/">DRBD</ulink> is required if you |
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want to use the high availability (HA) features of Ganeti, but |
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optional if you don't require HA or only run Ganeti on |
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single-node clusters. You can upgrade a non-HA cluster to an |
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HA one later, but you might need to export and re-import all |
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your instances to take advantage of the new features. |
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</para> |
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|
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<para> |
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Supported DRBD versions: <literal>8.0.x</literal>. |
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It's recommended to have at least version <literal>8.0.7</literal>. |
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</para> |
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|
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<para> |
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Now the bad news: unless your distribution already provides it |
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installing DRBD might involve recompiling your kernel or |
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anyway fiddling with it. Hopefully at least the Xen-ified |
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kernel source to start from will be provided. |
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</para> |
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|
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<para> |
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The good news is that you don't need to configure DRBD at all. |
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Ganeti will do it for you for every instance you set up. If |
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you have the DRBD utils installed and the module in your |
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kernel you're fine. Please check that your system is |
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configured to load the module at every boot, and that it |
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passes the following option to the module |
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<computeroutput>minor_count=255</computeroutput>. This will |
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allow you to use up to 128 instances per node (for most clusters |
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<constant>128 </constant> should be enough, though). |
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</para> |
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|
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<formalpara><title>Debian</title> |
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<para> |
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You can just install (build) the DRBD 8.0.x module with the |
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following commands (make sure you are running the Xen |
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kernel): |
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</para> |
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</formalpara> |
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|
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<screen> |
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apt-get install -t etch-backports drbd8-source drbd8-utils |
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m-a update |
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m-a a-i drbd8 |
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echo drbd minor_count=128 >> /etc/modules |
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depmod -a |
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modprobe drbd minor_count=128 |
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</screen> |
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|
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<para> |
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It is also recommended that you comment out the default |
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resources in the <filename>/etc/drbd.conf</filename> file, so |
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that the init script doesn't try to configure any drbd |
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devices. You can do this by prefixing all |
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<literal>resource</literal> lines in the file with the keyword |
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<literal>skip</literal>, like this: |
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</para> |
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|
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<screen> |
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skip resource r0 { |
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... |
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} |
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|
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skip resource "r1" { |
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... |
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} |
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</screen> |
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|
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</sect2> |
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|
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<sect2> |
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<title>Other required software</title> |
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|
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<para>Besides Xen and DRBD, you will need to install the |
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following (on all nodes):</para> |
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|
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<itemizedlist> |
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<listitem> |
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<simpara><ulink url="http://sourceware.org/lvm2/">LVM |
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version 2</ulink></simpara> |
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</listitem> |
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<listitem> |
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<simpara><ulink |
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url="http://www.openssl.org/">OpenSSL</ulink></simpara> |
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</listitem> |
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<listitem> |
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<simpara><ulink |
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url="http://www.openssh.com/portable.html">OpenSSH</ulink></simpara> |
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</listitem> |
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<listitem> |
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<simpara><ulink url="http://bridge.sourceforge.net/">Bridge |
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utilities</ulink></simpara> |
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</listitem> |
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<listitem> |
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<simpara><ulink |
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url="http://developer.osdl.org/dev/iproute2">iproute2</ulink></simpara> |
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</listitem> |
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<listitem> |
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<simpara><ulink |
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url="ftp://ftp.inr.ac.ru/ip-routing/iputils-current.tar.gz">arping</ulink> |
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(part of iputils package)</simpara> |
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</listitem> |
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<listitem> |
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<simpara><ulink url="http://www.python.org">Python 2.4</ulink></simpara> |
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</listitem> |
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<listitem> |
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<simpara><ulink |
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url="http://pyopenssl.sourceforge.net/">Python OpenSSL |
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bindings</ulink></simpara> |
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</listitem> |
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<listitem> |
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<simpara><ulink |
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url="http://www.undefined.org/python/#simplejson">simplejson Python |
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module</ulink></simpara> |
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</listitem> |
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<listitem> |
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<simpara><ulink |
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url="http://pyparsing.wikispaces.com/">pyparsing Python |
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module</ulink></simpara> |
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</listitem> |
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</itemizedlist> |
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|
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<para> |
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These programs are supplied as part of most Linux |
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distributions, so usually they can be installed via apt or |
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similar methods. Also many of them will already be installed |
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on a standard machine. |
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</para> |
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|
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|
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<formalpara><title>Debian</title> |
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|
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<para>You can use this command line to install all of them:</para> |
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|
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</formalpara> |
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<screen> |
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# apt-get install lvm2 ssh bridge-utils iproute iputils-arping \ |
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python2.4 python-pyopenssl openssl python-pyparsing python-simplejson |
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</screen> |
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|
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</sect2> |
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|
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</sect1> |
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|
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|
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<sect1> |
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<title>Setting up the environment for Ganeti</title> |
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|
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<sect2> |
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<title>Configuring the network</title> |
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|
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<para><emphasis role="strong">Mandatory</emphasis> on all nodes.</para> |
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|
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<para> |
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Ganeti relies on Xen running in "bridge mode", which means the |
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instances network interfaces will be attached to a software bridge |
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running in dom0. Xen by default creates such a bridge at startup, but |
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your distribution might have a different way to do things. |
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</para> |
467 |
|
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<para> |
469 |
Beware that the default name Ganeti uses is |
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<hardware>xen-br0</hardware> (which was used in Xen 2.0) |
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while Xen 3.0 uses <hardware>xenbr0</hardware> by |
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default. The default bridge your Ganeti cluster will use for new |
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instances can be specified at cluster initialization time. |
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</para> |
475 |
|
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<formalpara><title>Debian</title> |
477 |
<para> |
478 |
The recommended Debian way to configure the Xen bridge is to |
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edit your <filename>/etc/network/interfaces</filename> file |
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and substitute your normal Ethernet stanza with the |
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following snippet: |
482 |
|
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<screen> |
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auto xen-br0 |
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iface xen-br0 inet static |
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address <replaceable>YOUR_IP_ADDRESS</replaceable> |
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netmask <replaceable>YOUR_NETMASK</replaceable> |
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network <replaceable>YOUR_NETWORK</replaceable> |
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broadcast <replaceable>YOUR_BROADCAST_ADDRESS</replaceable> |
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gateway <replaceable>YOUR_GATEWAY</replaceable> |
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bridge_ports eth0 |
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bridge_stp off |
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bridge_fd 0 |
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</screen> |
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</para> |
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</formalpara> |
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|
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<para> |
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The following commands need to be executed on the local console |
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</para> |
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<screen> |
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ifdown eth0 |
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ifup xen-br0 |
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</screen> |
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|
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<para> |
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To check if the bridge is setup, use <command>ip</command> |
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and <command>brctl show</command>: |
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<para> |
510 |
|
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<screen> |
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# ip a show xen-br0 |
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9: xen-br0: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc noqueue |
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link/ether 00:20:fc:1e:d5:5d brd ff:ff:ff:ff:ff:ff |
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inet 10.1.1.200/24 brd 10.1.1.255 scope global xen-br0 |
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inet6 fe80::220:fcff:fe1e:d55d/64 scope link |
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valid_lft forever preferred_lft forever |
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|
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# brctl show xen-br0 |
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bridge name bridge id STP enabled interfaces |
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xen-br0 8000.0020fc1ed55d no eth0 |
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</screen> |
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|
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|
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</sect2> |
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|
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<sect2> |
528 |
<title>Configuring LVM</title> |
529 |
|
530 |
|
531 |
<para><emphasis role="strong">Mandatory</emphasis> on all nodes.</para> |
532 |
|
533 |
<note> |
534 |
<simpara>The volume group is required to be at least |
535 |
<constant>20GiB</constant>.</simpara> |
536 |
</note> |
537 |
<para> |
538 |
If you haven't configured your LVM volume group at install |
539 |
time you need to do it before trying to initialize the Ganeti |
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cluster. This is done by formatting the devices/partitions you |
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want to use for it and then adding them to the relevant volume |
542 |
group: |
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|
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<screen> |
545 |
pvcreate /dev/sda3 |
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vgcreate xenvg /dev/sda3 |
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</screen> |
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or |
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<screen> |
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pvcreate /dev/sdb1 |
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pvcreate /dev/sdc1 |
552 |
vgcreate xenvg /dev/sdb1 /dev/sdc1 |
553 |
</screen> |
554 |
</para> |
555 |
|
556 |
<para> |
557 |
If you want to add a device later you can do so with the |
558 |
<citerefentry><refentrytitle>vgextend</refentrytitle> |
559 |
<manvolnum>8</manvolnum></citerefentry> command: |
560 |
</para> |
561 |
|
562 |
<screen> |
563 |
pvcreate /dev/sdd1 |
564 |
vgextend xenvg /dev/sdd1 |
565 |
</screen> |
566 |
|
567 |
<formalpara> |
568 |
<title>Optional</title> |
569 |
<para> |
570 |
It is recommended to configure LVM not to scan the DRBD |
571 |
devices for physical volumes. This can be accomplished by |
572 |
editing <filename>/etc/lvm/lvm.conf</filename> and adding |
573 |
the <literal>/dev/drbd[0-9]+</literal> regular expression to |
574 |
the <literal>filter</literal> variable, like this: |
575 |
<screen> |
576 |
filter = [ "r|/dev/cdrom|", "r|/dev/drbd[0-9]+|" ] |
577 |
</screen> |
578 |
</para> |
579 |
</formalpara> |
580 |
|
581 |
</sect2> |
582 |
|
583 |
<sect2> |
584 |
<title>Installing Ganeti</title> |
585 |
|
586 |
<para><emphasis role="strong">Mandatory</emphasis> on all nodes.</para> |
587 |
|
588 |
<para> |
589 |
It's now time to install the Ganeti software itself. Download |
590 |
the source from <ulink |
591 |
url="http://code.google.com/p/ganeti/"></ulink>. |
592 |
</para> |
593 |
|
594 |
<screen> |
595 |
tar xvzf ganeti-@GANETI_VERSION@.tar.gz |
596 |
cd ganeti-@GANETI_VERSION@ |
597 |
./configure --localstatedir=/var --sysconfdir=/etc |
598 |
make |
599 |
make install |
600 |
mkdir /srv/ganeti/ /srv/ganeti/os /srv/ganeti/export |
601 |
</screen> |
602 |
|
603 |
<para> |
604 |
You also need to copy the file |
605 |
<filename>doc/examples/ganeti.initd</filename> |
606 |
from the source archive to |
607 |
<filename>/etc/init.d/ganeti</filename> and register it with |
608 |
your distribution's startup scripts, for example in Debian: |
609 |
</para> |
610 |
<screen>update-rc.d ganeti defaults 20 80</screen> |
611 |
|
612 |
<para> |
613 |
In order to automatically restart failed instances, you need |
614 |
to setup a cron job run the |
615 |
<computeroutput>ganeti-watcher</computeroutput> program. A |
616 |
sample cron file is provided in the source at |
617 |
<filename>doc/examples/ganeti.cron</filename> and you can |
618 |
copy that (eventually altering the path) to |
619 |
<filename>/etc/cron.d/ganeti</filename> |
620 |
</para> |
621 |
|
622 |
</sect2> |
623 |
|
624 |
<sect2> |
625 |
<title>Installing the Operating System support packages</title> |
626 |
|
627 |
<para><emphasis role="strong">Mandatory</emphasis> on all nodes.</para> |
628 |
|
629 |
<para> |
630 |
To be able to install instances you need to have an Operating |
631 |
System installation script. An example for Debian Etch is |
632 |
provided on the project web site. Download it from <ulink |
633 |
url="http://code.google.com/p/ganeti/"></ulink> and follow the |
634 |
instructions in the <filename>README</filename> file. Here is |
635 |
the installation procedure (replace <constant>0.2</constant> |
636 |
with the latest version that is compatible with your ganeti |
637 |
version): |
638 |
</para> |
639 |
|
640 |
<screen> |
641 |
cd /srv/ganeti/os |
642 |
tar xvf ganeti-instance-debian-etch-0.4.tar |
643 |
mv ganeti-instance-debian-etch-0.4 debian-etch |
644 |
</screen> |
645 |
|
646 |
<para> |
647 |
In order to use this OS definition, you need to have internet |
648 |
access from your nodes and have the <citerefentry> |
649 |
<refentrytitle>debootstrap</refentrytitle> |
650 |
<manvolnum>8</manvolnum></citerefentry>, <citerefentry> |
651 |
<refentrytitle>dump</refentrytitle><manvolnum>8</manvolnum> |
652 |
</citerefentry> and <citerefentry> |
653 |
<refentrytitle>restore</refentrytitle> |
654 |
<manvolnum>8</manvolnum> </citerefentry> commands installed on |
655 |
all nodes. |
656 |
</para> |
657 |
<formalpara> |
658 |
<title>Debian</title> |
659 |
<para> |
660 |
Use this command on all nodes to install the required |
661 |
packages: |
662 |
|
663 |
<screen>apt-get install debootstrap dump</screen> |
664 |
</para> |
665 |
</formalpara> |
666 |
|
667 |
<para> |
668 |
Alternatively, you can create your own OS definitions. See the |
669 |
manpage |
670 |
<citerefentry> |
671 |
<refentrytitle>ganeti-os-interface</refentrytitle> |
672 |
<manvolnum>8</manvolnum> |
673 |
</citerefentry>. |
674 |
</para> |
675 |
|
676 |
</sect2> |
677 |
|
678 |
<sect2> |
679 |
<title>Initializing the cluster</title> |
680 |
|
681 |
<para><emphasis role="strong">Mandatory:</emphasis> only on one |
682 |
node per cluster.</para> |
683 |
|
684 |
|
685 |
<para>The last step is to initialize the cluster. After you've repeated |
686 |
the above process on all of your nodes, choose one as the master, and execute: |
687 |
</para> |
688 |
|
689 |
<screen> |
690 |
gnt-cluster init <replaceable>CLUSTERNAME</replaceable> |
691 |
</screen> |
692 |
|
693 |
<para> |
694 |
The <replaceable>CLUSTERNAME</replaceable> is a hostname, |
695 |
which must be resolvable (e.g. it must exist in DNS or in |
696 |
<filename>/etc/hosts</filename>) by all the nodes in the |
697 |
cluster. You must choose a name different from any of the |
698 |
nodes names for a multi-node cluster. In general the best |
699 |
choice is to have a unique name for a cluster, even if it |
700 |
consists of only one machine, as you will be able to expand it |
701 |
later without any problems. |
702 |
</para> |
703 |
|
704 |
<para> |
705 |
If the bridge name you are using is not |
706 |
<literal>xen-br0</literal>, use the <option>-b |
707 |
<replaceable>BRIDGENAME</replaceable></option> option to |
708 |
specify the bridge name. In this case, you should also use the |
709 |
<option>--master-netdev |
710 |
<replaceable>BRIDGENAME</replaceable></option> option with the |
711 |
same <replaceable>BRIDGENAME</replaceable> argument. |
712 |
</para> |
713 |
|
714 |
<para> |
715 |
You can use a different name than <literal>xenvg</literal> for |
716 |
the volume group (but note that the name must be identical on |
717 |
all nodes). In this case you need to specify it by passing the |
718 |
<option>-g <replaceable>VGNAME</replaceable></option> option |
719 |
to <computeroutput>gnt-cluster init</computeroutput>. |
720 |
</para> |
721 |
|
722 |
<para> |
723 |
To set up the cluster as an HVM cluster, use the |
724 |
<option>--hypervisor=xen-hvm3.1</option> option to use |
725 |
the Xen 3.1 HVM hypervisor. Note that with the |
726 |
HVM support, you will only be able to create |
727 |
HVM instances in a cluster set to this hypervisor type. Mixed |
728 |
PVM/HVM clusters are not supported by the Ganeti 1.2 |
729 |
HVM support. You will also need to create the VNC |
730 |
cluster password file |
731 |
<filename>/etc/ganeti/vnc-cluster-password</filename> |
732 |
which contains one line with the default VNC password for the |
733 |
cluster. |
734 |
</para> |
735 |
|
736 |
<para> |
737 |
You can also invoke the command with the |
738 |
<option>--help</option> option in order to see all the |
739 |
possibilities. |
740 |
</para> |
741 |
|
742 |
</sect2> |
743 |
|
744 |
<sect2> |
745 |
<title>Joining the nodes to the cluster</title> |
746 |
|
747 |
<para> |
748 |
<emphasis role="strong">Mandatory:</emphasis> for all the |
749 |
other nodes. |
750 |
</para> |
751 |
|
752 |
<para> |
753 |
After you have initialized your cluster you need to join the |
754 |
other nodes to it. You can do so by executing the following |
755 |
command on the master node: |
756 |
</para> |
757 |
<screen> |
758 |
gnt-node add <replaceable>NODENAME</replaceable> |
759 |
</screen> |
760 |
</sect2> |
761 |
|
762 |
<sect2> |
763 |
<title>Separate replication network</title> |
764 |
|
765 |
<para><emphasis role="strong">Optional</emphasis></para> |
766 |
<para> |
767 |
Ganeti uses DRBD to mirror the disk of the virtual instances |
768 |
between nodes. To use a dedicated network interface for this |
769 |
(in order to improve performance or to enhance security) you |
770 |
need to configure an additional interface for each node. Use |
771 |
the <option>-s</option> option with |
772 |
<computeroutput>gnt-cluster init</computeroutput> and |
773 |
<computeroutput>gnt-node add</computeroutput> to specify the |
774 |
IP address of this secondary interface to use for each |
775 |
node. Note that if you specified this option at cluster setup |
776 |
time, you must afterwards use it for every node add operation. |
777 |
</para> |
778 |
</sect2> |
779 |
|
780 |
<sect2> |
781 |
<title>Testing the setup</title> |
782 |
|
783 |
<para> |
784 |
Execute the <computeroutput>gnt-node list</computeroutput> |
785 |
command to see all nodes in the cluster: |
786 |
<screen> |
787 |
# gnt-node list |
788 |
Node DTotal DFree MTotal MNode MFree Pinst Sinst |
789 |
node1.example.com 197404 197404 2047 1896 125 0 0 |
790 |
</screen> |
791 |
</para> |
792 |
</sect2> |
793 |
|
794 |
<sect1> |
795 |
<title>Setting up and managing virtual instances</title> |
796 |
<sect2> |
797 |
<title>Setting up virtual instances</title> |
798 |
<para> |
799 |
This step shows how to setup a virtual instance with either |
800 |
non-mirrored disks (<computeroutput>plain</computeroutput>) or |
801 |
with network mirrored disks |
802 |
(<computeroutput>drbd</computeroutput>). All |
803 |
commands need to be executed on the Ganeti master node (the |
804 |
one on which <computeroutput>gnt-cluster init</computeroutput> |
805 |
was run). Verify that the OS scripts are present on all |
806 |
cluster nodes with <computeroutput>gnt-os |
807 |
list</computeroutput>. |
808 |
</para> |
809 |
<para> |
810 |
To create a virtual instance, you need a hostname which is |
811 |
resolvable (DNS or <filename>/etc/hosts</filename> on all |
812 |
nodes). The following command will create a non-mirrored |
813 |
instance for you: |
814 |
</para> |
815 |
<screen> |
816 |
gnt-instance add --node=node1 -o debian-etch -t plain inst1.example.com |
817 |
* creating instance disks... |
818 |
adding instance inst1.example.com to cluster config |
819 |
Waiting for instance inst1.example.com to sync disks. |
820 |
Instance inst1.example.com's disks are in sync. |
821 |
creating os for instance inst1.example.com on node node1.example.com |
822 |
* running the instance OS create scripts... |
823 |
</screen> |
824 |
|
825 |
<para> |
826 |
The above instance will have no network interface enabled. |
827 |
You can access it over the virtual console with |
828 |
<computeroutput>gnt-instance console |
829 |
<literal>inst1</literal></computeroutput>. There is no |
830 |
password for root. As this is a Debian instance, you can |
831 |
modify the <filename>/etc/network/interfaces</filename> file |
832 |
to setup the network interface (<literal>eth0</literal> is the |
833 |
name of the interface provided to the instance). |
834 |
</para> |
835 |
|
836 |
<para> |
837 |
To create a network mirrored instance, change the argument to |
838 |
the <option>-t</option> option from <literal>plain</literal> |
839 |
to <literal>drbd</literal> and specify the node on |
840 |
which the mirror should reside with the second value of the |
841 |
<option>--node</option> option, like this: |
842 |
</para> |
843 |
|
844 |
<screen> |
845 |
# gnt-instance add -t drbd -n node1:node2 -o debian-etch instance2 |
846 |
* creating instance disks... |
847 |
adding instance instance2 to cluster config |
848 |
Waiting for instance instance1 to sync disks. |
849 |
- device sdb: 3.50% done, 304 estimated seconds remaining |
850 |
- device sdb: 21.70% done, 270 estimated seconds remaining |
851 |
- device sdb: 39.80% done, 247 estimated seconds remaining |
852 |
- device sdb: 58.10% done, 121 estimated seconds remaining |
853 |
- device sdb: 76.30% done, 72 estimated seconds remaining |
854 |
- device sdb: 94.80% done, 18 estimated seconds remaining |
855 |
Instance instance2's disks are in sync. |
856 |
creating os for instance instance2 on node node1.example.com |
857 |
* running the instance OS create scripts... |
858 |
* starting instance... |
859 |
</screen> |
860 |
|
861 |
</sect2> |
862 |
|
863 |
<sect2> |
864 |
<title>Managing virtual instances</title> |
865 |
<para> |
866 |
All commands need to be executed on the Ganeti master node |
867 |
</para> |
868 |
|
869 |
<para> |
870 |
To access the console of an instance, use |
871 |
<computeroutput>gnt-instance console |
872 |
<replaceable>INSTANCENAME</replaceable></computeroutput>. |
873 |
</para> |
874 |
|
875 |
<para> |
876 |
To shutdown an instance, use <computeroutput>gnt-instance |
877 |
shutdown |
878 |
<replaceable>INSTANCENAME</replaceable></computeroutput>. To |
879 |
startup an instance, use <computeroutput>gnt-instance startup |
880 |
<replaceable>INSTANCENAME</replaceable></computeroutput>. |
881 |
</para> |
882 |
|
883 |
<para> |
884 |
To failover an instance to its secondary node (only possible |
885 |
with <literal>drbd</literal> disk templates), use |
886 |
<computeroutput>gnt-instance failover |
887 |
<replaceable>INSTANCENAME</replaceable></computeroutput>. |
888 |
</para> |
889 |
|
890 |
<para> |
891 |
For more instance and cluster administration details, see the |
892 |
<emphasis>Ganeti administrator's guide</emphasis>. |
893 |
</para> |
894 |
|
895 |
</sect2> |
896 |
|
897 |
</sect1> |
898 |
|
899 |
</article> |