46 lines
2.9 KiB
XML
46 lines
2.9 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"
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version="5.0"
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xml:id="nova_cli_evacuate">
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<title>Evacuate instances</title>
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<para>If a cloud compute node fails due to a hardware malfunction or another reason, you can
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evacuate instances to make them available again. You can optionally include the target host
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on the <command>evacuate</command> command. If you omit the host, the scheduler determines
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the target host.</para>
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<para>To preserve user data on server disk, you must configure shared storage on the target
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host. Also, you must validate that the current VM host is down; otherwise, the evacuation
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fails with an error.</para>
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<procedure xml:id="evacuate_shared">
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<step>
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<para>To list hosts and find a different host for the evacuated instance, run:</para>
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<screen><prompt>$</prompt> <userinput>nova host-list</userinput></screen>
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</step>
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<step>
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<para>Evacuate the instance. You can pass the instance password to the command by using
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the <literal>--password <pwd></literal> option. If you do not specify a
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password, one is generated and printed after the command finishes successfully. The
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following command evacuates a server without shared storage from a host that is down
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to the specified <replaceable>host_b</replaceable>:</para>
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<screen><prompt>$</prompt> <userinput>nova evacuate <replaceable>evacuated_server_name</replaceable> <replaceable>host_b</replaceable></userinput> </screen>
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<para>The instance is booted from a new disk, but preserves its configuration including
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its ID, name, uid, IP address, and so on. The command returns a password:</para>
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<screen><computeroutput><?db-font-size 70%?>+-----------+--------------+
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| Property | Value |
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+-----------+--------------+
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| adminPass | kRAJpErnT4xZ |
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+-----------+--------------+</computeroutput></screen>
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</step>
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<step>
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<para>To preserve the user disk data on the evacuated server, deploy OpenStack Compute
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with a shared file system. To configure your system, see <link
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xlink:href="http://docs.openstack.org/admin-guide-cloud/content/section_configuring-compute-migrations.html"
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>Configure migrations</link> in <citetitle>OpenStack Cloud Administrator
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Guide</citetitle>. In the following example, the password remains
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unchanged:</para>
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<screen><prompt>$</prompt> <userinput>nova evacuate <replaceable>evacuated_server_name</replaceable> <replaceable>host_b</replaceable> --on-shared-storage</userinput> </screen>
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</step>
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</procedure>
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</section>
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