b609bdc20e
The API reference already says this [1] so the doc should also. [1] https://docs.openstack.org/api-ref/compute/?expanded=rescue-server-rescue-action-detail#rescue-server-rescue-action Change-Id: I085bb3f01802332fcf4820d3ead6f74785dff8b9
56 lines
1.8 KiB
ReStructuredText
56 lines
1.8 KiB
ReStructuredText
==================
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Rescue an instance
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==================
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Rescue mode provides a mechanism for access, even if an image renders
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the instance inaccessible. By default, it starts an instance from the
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initial image attaching the current boot disk as a secondary one.
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.. note::
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Pause, suspend, and stop operations are not allowed when an instance
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is running in rescue mode, as triggering these actions causes the
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loss of the original instance state and makes it impossible to
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unrescue the instance.
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As of the 20.0.0 (Train) release rescuing a volume-backed server
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is not supported.
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To perform an instance rescue, use the :command:`openstack server rescue`
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command:
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.. code-block:: console
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$ openstack server rescue SERVER
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.. note::
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On running the :command:`openstack server rescue` command,
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an instance performs a soft shutdown first. This means that
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the guest operating system has a chance to perform
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a controlled shutdown before the instance is powered off.
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The shutdown behavior is configured by the
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:oslo.config:option:`shutdown_timeout` parameter that can be set in the
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``nova.conf`` file.
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Its value stands for the overall period (in seconds)
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a guest operating system is allowed to complete the shutdown.
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The timeout value can be overridden on a per image basis
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by means of ``os_shutdown_timeout`` that is an image metadata
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setting allowing different types of operating systems to specify
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how much time they need to shut down cleanly.
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If you want to rescue an instance with a specific image, rather than the
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default one, use the ``--image`` parameter:
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.. code-block:: console
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$ openstack server rescue --image IMAGE_ID SERVER
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To restart the instance from the normal boot disk, run the following
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command:
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.. code-block:: console
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$ openstack server unrescue SERVER
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