Boot from rescue image¶

Sometimes you need to boot your instance from an ISO image because the mounted filesystem on the boot volume prevents you from fixing certain issues.

You can use a rescue image in these scenarios to boot an alternate operating system, which can then fix problems with the volume.

The Cloud management portal includes a rescue function, but it only lets you mount a rescue image on instances that don’t boot from a volume. We’ll focus on how to use the OpenStack Terminal Client instead to workaround this limitation.

OpenStack Terminal Client¶

To boot your instance from a rescue image by using the OpenStack Terminal Client

• We provide a public SystemRescue image that you can use.

• You can use a custom rescue image or use our guide here to create one.

• To connect the image to the instance run the command openstack --os-compute-api-version 2.87 server rescue --image <ISO_NAME> <INSTANCE_NAME>, replacing <ISO_NAME> with the name from previous step and <INSTANCE_NAME> with the name of the instance that should mount the image.

  • It will take up to a few minutes to add the rescue image and for the instance to start. Use the console to manage the instance when it’s done.

• When you’re done with the rescue remove the rescue image from the instance by running the command openstack server unrescue <INSTANCE_NAME>.