diff options
author | Zuul <zuul@review.opendev.org> | 2020-04-21 13:05:08 +0000 |
---|---|---|
committer | Gerrit Code Review <review@openstack.org> | 2020-04-21 13:05:08 +0000 |
commit | 58aaffade9f78c5fdc6b0d26ec26b70908b7a6aa (patch) | |
tree | 2adb833e7e5fa55f9553e7a228f580efd94508fa | |
parent | b0cc9bad3ae4a5668c042ab17e8422eb999c039d (diff) | |
parent | 30fcb2ddfd2ab5ef26df9a6726806b011d335f31 (diff) | |
download | nova-58aaffade9f78c5fdc6b0d26ec26b70908b7a6aa.tar.gz |
Merge "docs: Add stable device rescue docs"
-rw-r--r-- | doc/source/user/rescue.rst | 51 |
1 files changed, 45 insertions, 6 deletions
diff --git a/doc/source/user/rescue.rst b/doc/source/user/rescue.rst index 3ac940bea1..8a50fe1114 100644 --- a/doc/source/user/rescue.rst +++ b/doc/source/user/rescue.rst @@ -2,9 +2,51 @@ 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. +Instance rescue provides a mechanism for access, even if an image renders the +instance inaccessible. Two rescue modes are currently provided. + +Instance rescue +--------------- + +By default the instance is booted from the provided rescue image or a fresh +copy of the original instance image if a rescue image is not provided. The root +disk and optional regenerated config drive are also attached to the instance +for data recovery. + +.. note:: + + Rescuing a volume-backed instance is not supported with this mode. + +Stable device instance rescue +----------------------------- + +As of 21.0.0 (Ussuri) an additional stable device rescue mode is available. +This mode now supports the rescue of volume-backed instances. + +This mode keeps all devices both local and remote attached in their original +order to the instance during the rescue while booting from the provided rescue +image. This mode is enabled and controlled by the presence of +``hw_rescue_device`` or ``hw_rescue_bus`` image properties on the provided +rescue image. + +As their names suggest these properties control the rescue device type +(``cdrom``, ``disk`` or ``floppy``) and bus type (``scsi``, ``virtio``, +``ide``, or ``usb``) used when attaching the rescue image to the instance. + +Support for each combination of the ``hw_rescue_device`` and ``hw_rescue_bus`` +image properties is dependent on the underlying hypervisor and platform being +used. For example the ``IDE`` bus is not available on POWER KVM based compute +hosts. + +.. note:: + + This mode is only supported when using the Libvirt virt driver. + + This mode is not supported when using LXC or Xen hypervisors as enabled by + the :oslo.config:option:`libvirt.virt_type` configurable on the computes. + +Usage +----- .. note:: @@ -13,9 +55,6 @@ initial image attaching the current boot disk as a secondary one. loss of the original instance state and makes it impossible to unrescue the instance. - As of the 20.0.0 (Train) release rescuing a volume-backed server - is not supported. - To perform an instance rescue, use the :command:`openstack server rescue` command: |