The Bare Metal Service supports putting nodes in rescue mode using hardware
types that support rescue interfaces. The hardware types utilizing
Virtual Media based boot interface can
support rescue operation when configured appropriately.
The rescue operation is currently supported only when tenant networks use DHCP to obtain IP addresses.
Rescue operation can be used to boot nodes into a rescue ramdisk so that the
rescue user can access the node, in order to provide the ability to
access the node in case access to OS is not possible.
For example, if there is a need to perform manual password reset or data
recovery in the event of some failure, rescue operation can be used.
Configuring The Bare Metal Service¶
Configure the Bare Metal Service appropriately so that the service has the information needed to boot the ramdisk before a user tries to initiate rescue operation. This will differ somewhat between different deploy environments, but an example of how to do this is outlined below:
Create and configure ramdisk that supports rescue operation. Please see Building or downloading a deploy ramdisk image for detailed instructions to build a ramdisk.
Configure a network to use for booting nodes into the rescue ramdisk in neutron, and note the UUID or name of this network. This is required if you’re using the neutron DHCP provider and have Bare Metal Service managing ramdisk booting (the default). This can be the same network as your cleaning or tenant network (for flat network). For an example of how to configure new networks with Bare Metal Service, see the Configure the Networking service for bare metal provisioning documentation.
Add the unique name or UUID of your rescue network to
This can be set per node via driver_info[‘rescuing_network’]
Restart the ironic conductor service.
Specify a rescue kernel and ramdisk or rescue ISO compatible with the node’s driver for pxe based boot interface or virtual-media based boot interface respectively.
Example for pxe based boot interface:
baremetal node set $NODE_UUID \ --driver-info rescue_ramdisk=$RESCUE_INITRD_UUID \ --driver-info rescue_kernel=$RESCUE_VMLINUZ_UUID
See Add images to the Image service for details. If you are not using Image service, it is possible to provide images to Bare Metal service via hrefs.
After this, The Bare Metal Service should be ready for
Test it out by attempting to rescue an active node and connect to the instance
using ssh, as given below:
baremetal node rescue $NODE_UUID \ --rescue-password <PASSWORD> --wait ssh rescue@$INSTANCE_IP_ADDRESS
To move a node back to active state after using rescue mode you can
unrescue. Please unmount any filesystems that were manually mounted
before proceeding with unrescue. The node unrescue can be done as given below:
baremetal node unrescue $NODE_UUID
unrescue operations can also be triggered via the Compute
Service using the following commands:
openstack server rescue --password <password> <server> openstack server unrescue <server>