f9cdba79aa
Docs on a plane returns. A cohort of small changes, reducing cruft and improving clarity of these common sections. Change-Id: I11c0ee83f4b2805304bb2e84e548c0a6aeaa135e
87 lines
5.9 KiB
XML
87 lines
5.9 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<section xmlns="http://docbook.org/ns/docbook"
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xmlns:xi="http://www.w3.org/2001/XInclude"
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xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0"
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xml:id="configuring-multiple-compute-nodes">
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<title>Configuring Multiple Compute Nodes</title>
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<para>If your goal is to split your VM load across more than one
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server, you can connect an additional <systemitem
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class="service">nova-compute</systemitem> node to a cloud
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controller node. This configuring can be reproduced on
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multiple compute servers to start building a true multi-node
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OpenStack Compute cluster.</para>
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<para>To build out and scale the Compute platform, you spread
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out services amongst many servers. While there are additional
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ways to accomplish the build-out, this section describes
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adding compute nodes, and the service we are scaling out is
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called <systemitem class="service"
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>nova-compute</systemitem>.</para>
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<para>For a multi-node install you only make changes to
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<filename>nova.conf</filename> and copy it to additional
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compute nodes. Ensure each <filename>nova.conf</filename> file
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points to the correct IP addresses for the respective
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services.</para>
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<para>By default, <systemitem class="service">nova-network</systemitem>
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sets the bridge device based on the
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setting in <literal>flat_network_bridge</literal>. Now you can
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edit <filename>/etc/network/interfaces</filename> with the
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following template, updated with your IP information.</para>
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<programlisting language="bash"># The loopback network interface
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auto lo
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iface lo inet loopback
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# The primary network interface
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auto br100
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iface br100 inet static
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bridge_ports eth0
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bridge_stp off
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bridge_maxwait 0
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bridge_fd 0
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address <replaceable>xxx.xxx.xxx.xxx</replaceable>
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netmask <replaceable>xxx.xxx.xxx.xxx</replaceable>
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network <replaceable>xxx.xxx.xxx.xxx</replaceable>
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broadcast <replaceable>xxx.xxx.xxx.xxx</replaceable>
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gateway <replaceable>xxx.xxx.xxx.xxx</replaceable>
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# dns-* options are implemented by the resolvconf package, if installed
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dns-nameservers <replaceable>xxx.xxx.xxx.xxx</replaceable></programlisting>
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<para>Restart networking:</para>
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<screen><prompt>$</prompt> <userinput>sudo service networking restart</userinput></screen>
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<para>With <filename>nova.conf</filename> updated and networking
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set, configuration is nearly complete. First, bounce the
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relevant services to take the latest updates:</para>
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<screen><prompt>$</prompt> <userinput>sudo service libvirtd restart</userinput>
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$ <userinput>sudo service nova-compute restart</userinput></screen>
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<para>To avoid issues with KVM and permissions with Nova, run
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the following commands to ensure we have VM's that are running
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optimally:</para>
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<screen><prompt>#</prompt> <userinput>chgrp kvm /dev/kvm</userinput>
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<prompt>#</prompt> <userinput>chmod g+rwx /dev/kvm</userinput></screen>
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<para>Any server that does not have
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<command>nova-api</command> running on it needs this
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iptables entry so that images can get metadata info. On
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compute nodes, configure the iptables with this next
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step:</para>
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<screen><prompt>#</prompt> <userinput>iptables -t nat -A PREROUTING -d 169.254.169.254/32 -p tcp -m tcp --dport 80 -j DNAT --to-destination <replaceable>$NOVA_API_IP</replaceable>:8773</userinput></screen>
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<para>Lastly, confirm that your compute node is talking to your
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cloud controller. From the cloud controller, run this database
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query:</para>
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<screen><prompt>$</prompt> <userinput>mysql -u<replaceable>$MYSQL_USER</replaceable> -p<replaceable>$MYSQL_PASS</replaceable> nova -e 'select * from services;'</userinput></screen>
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<para>In return, you should see something similar to
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this:</para> <screen><computeroutput>+---------------------+---------------------+------------+---------+----+----------+----------------+-----------+--------------+----------+-------------------+
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| created_at | updated_at | deleted_at | deleted | id | host | binary | topic | report_count | disabled | availability_zone |
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+---------------------+---------------------+------------+---------+----+----------+----------------+-----------+--------------+----------+-------------------+
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| 2011-01-28 22:52:46 | 2011-02-03 06:55:48 | NULL | 0 | 1 | osdemo02 | nova-network | network | 46064 | 0 | nova |
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| 2011-01-28 22:52:48 | 2011-02-03 06:55:57 | NULL | 0 | 2 | osdemo02 | nova-compute | compute | 46056 | 0 | nova |
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| 2011-01-28 22:52:52 | 2011-02-03 06:55:50 | NULL | 0 | 3 | osdemo02 | nova-scheduler | scheduler | 46065 | 0 | nova |
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| 2011-01-29 23:49:29 | 2011-02-03 06:54:26 | NULL | 0 | 4 | osdemo01 | nova-compute | compute | 37050 | 0 | nova |
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| 2011-01-30 23:42:24 | 2011-02-03 06:55:44 | NULL | 0 | 9 | osdemo04 | nova-compute | compute | 28484 | 0 | nova |
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| 2011-01-30 21:27:28 | 2011-02-03 06:54:23 | NULL | 0 | 8 | osdemo05 | nova-compute | compute | 29284 | 0 | nova |
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+---------------------+---------------------+------------+---------+----+----------+----------------+-----------+--------------+----------+-------------------+</computeroutput></screen>
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<para>You can see that <literal>osdemo0{1,2,4,5}</literal> are
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all running <systemitem class="service"
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>nova-compute</systemitem>. When you start spinning up
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instances, they will allocate on any node that is running
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<systemitem class="service">nova-compute</systemitem> from
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this list.</para>
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</section>
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