54 lines
2.9 KiB
XML
54 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" 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
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or another reason, you can evacuate instances to make them
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available again.</para>
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<para>You can choose evacuation parameters for your use
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case.</para>
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<para>To preserve user data on server disk, you must configure
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shared storage on the target host. Also, you must validate
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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 find a different host for the evacuated instance,
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run this command to list hosts:</para>
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<screen><prompt>$</prompt> <userinput>nova host-list</userinput></screen>
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</step>
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<step>
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<para>You can pass the instance password to the command by
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using the <literal>--password <pwd></literal>
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option. If you do not specify a password, one is
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generated and printed after the command finishes
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successfully. The following command evacuates a server
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without shared storage:</para>
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<screen><prompt>$</prompt> <userinput>nova evacuate <replaceable>evacuated_server_name</replaceable> <replaceable>host_b</replaceable></userinput> </screen>
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<para>The command evacuates an instance from a down host
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to a specified host. The instance is booted from a new
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disk, but preserves its configuration including its
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ID, name, uid, IP address, and so on. The command
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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
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server, deploy OpenStack Compute with shared file
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system. To configure your system, see <link
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xlink:href="http://docs.openstack.org/havana/config-reference/content/configuring-openstack-compute-basics.html#section_configuring-compute-migrations"
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>Configure migrations</link> in
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<citetitle>OpenStack Configuration
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Reference</citetitle>. In this example, the
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password remains 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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