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Merge "docs: Extract rescue from reboot"

changes/17/694717/1
Zuul 3 weeks ago
parent
commit
1c7437e345
3 changed files with 55 additions and 51 deletions
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      doc/source/user/index.rst
  2. +2
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      doc/source/user/reboot.rst
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      doc/source/user/rescue.rst

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doc/source/user/index.rst View File

@@ -15,6 +15,7 @@ End user guide
certificate-validation
resize
reboot
rescue
availability-zones
block-device-mapping
/reference/api-microversion-history

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doc/source/user/reboot.rst View File

@@ -20,54 +20,5 @@ To perform a hard reboot, pass the ``--hard`` parameter as follows:
$ openstack server reboot --hard SERVER

It is also possible to reboot a running instance into rescue mode. For example,
this operation may be required if a filesystem of an instance becomes
corrupted with prolonged use.

.. note::

Pause, suspend, and stop operations are not allowed when an instance
is running in rescue mode, as triggering these actions causes the
loss of the original instance state and makes it impossible to
unrescue the instance.

Rescue mode provides a mechanism for access, even if an image renders
the instance inaccessible. By default, it starts an instance from the
initial image attaching the current boot disk as a secondary one.

To perform an instance reboot into rescue mode, use the :command:`openstack
server rescue` command:

.. code-block:: console

$ openstack server rescue SERVER

.. note::

On running the :command:`openstack server rescue` command,
an instance performs a soft shutdown first. This means that
the guest operating system has a chance to perform
a controlled shutdown before the instance is powered off.
The shutdown behavior is configured by the
:oslo.config:option:`shutdown_timeout` parameter that can be set in the
``nova.conf`` file.
Its value stands for the overall period (in seconds)
a guest operating system is allowed to complete the shutdown.

The timeout value can be overridden on a per image basis
by means of ``os_shutdown_timeout`` that is an image metadata
setting allowing different types of operating systems to specify
how much time they need to shut down cleanly.

To restart the instance from the normal boot disk, run the following
command:

.. code-block:: console

$ openstack server unrescue SERVER

If you want to rescue an instance with a specific image, rather than the
default one, use the ``--image`` parameter:

.. code-block:: console

$ openstack server rescue --image IMAGE_ID SERVER
this operation may be required if a filesystem of an instance becomes corrupted
with prolonged use. See :doc:`rescue` for more details.

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doc/source/user/rescue.rst View File

@@ -0,0 +1,52 @@
==================
Rescue an instance
==================

Rescue mode provides a mechanism for access, even if an image renders
the instance inaccessible. By default, it starts an instance from the
initial image attaching the current boot disk as a secondary one.

.. note::

Pause, suspend, and stop operations are not allowed when an instance
is running in rescue mode, as triggering these actions causes the
loss of the original instance state and makes it impossible to
unrescue the instance.

To perform an instance rescue, use the :command:`openstack server rescue`
command:

.. code-block:: console

$ openstack server rescue SERVER

.. note::

On running the :command:`openstack server rescue` command,
an instance performs a soft shutdown first. This means that
the guest operating system has a chance to perform
a controlled shutdown before the instance is powered off.
The shutdown behavior is configured by the
:oslo.config:option:`shutdown_timeout` parameter that can be set in the
``nova.conf`` file.
Its value stands for the overall period (in seconds)
a guest operating system is allowed to complete the shutdown.

The timeout value can be overridden on a per image basis
by means of ``os_shutdown_timeout`` that is an image metadata
setting allowing different types of operating systems to specify
how much time they need to shut down cleanly.

If you want to rescue an instance with a specific image, rather than the
default one, use the ``--image`` parameter:

.. code-block:: console

$ openstack server rescue --image IMAGE_ID SERVER

To restart the instance from the normal boot disk, run the following
command:

.. code-block:: console

$ openstack server unrescue SERVER

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