51 lines
1.9 KiB
ReStructuredText
51 lines
1.9 KiB
ReStructuredText
==================
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Evacuate instances
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==================
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If a hardware malfunction or other error causes a cloud compute node to fail,
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you can evacuate instances to make them available again. You can optionally
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include the target host on the :command:`nova evacuate` command. If you omit
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the host, the scheduler chooses the target host.
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To preserve user data on the server disk, configure shared storage on the
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target host. When you evacuate the instance, Compute detects whether shared
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storage is available on the target host. Also, you must validate that the
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current VM host is not operational. Otherwise, the evacuation fails.
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#. To find a host for the evacuated instance, list all hosts:
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.. code-block:: console
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$ nova host-list
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#. Evacuate the instance. You can use the :option:`--password PWD` option
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to pass the instance password to the command. If you do not specify a
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password, the command generates and prints one after it finishes
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successfully. The following command evacuates a server from a failed host
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to HOST_B.
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.. code-block:: console
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$ nova evacuate EVACUATED_SERVER_NAME HOST_B
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The command rebuilds the instance from the original image or volume and
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returns a password. The command preserves the original configuration, which
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includes the instance ID, name, uid, IP address, and so on.
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.. code-block:: console
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+-----------+--------------+
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| Property | Value |
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+-----------+--------------+
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| adminPass | kRAJpErnT4xZ |
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+-----------+--------------+
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#. To preserve the user disk data on the evacuated server, deploy Compute
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with a shared file system. To configure your system, see
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:ref:`section_configuring-compute-migrations`.
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The following example does not change the password.
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.. code-block:: console
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$ nova evacuate EVACUATED_SERVER_NAME HOST_B --on-shared-storage
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