4.7.3. Launching an instance in rescue mode

Because you need to rescue an instance with a specific image, rather than the default one, use the --image parameter:
```
# openstack server rescue --image <image> <instance>
```
- Replace <image> with the name or ID of the image you want to use.
- Replace <instance> with the name or ID of the instance that you want to rescue.
注記
For more information on rescuing an instance, see https://access.redhat.com/documentation/en-us/red_hat_openstack_platform/16.1/html/instances_and_images_guide/assembly-managing-an-instance_instances#rescuing-an-instance_instances
By default, the instance has 60 seconds to shut down. You can override the timeout value on a per image basis by using the image metadata setting os_shutdown_timeout to specify the time that different types of operating systems require to shut down cleanly.
Reboot the virtual machine.
Confirm the status of the virtual machine is RESCUE on the controller node by using nova list command or by using dashboard.
Log in to the new virtual machine dashboard by using the password for rescue mode.

You can now make the necessary changes to your instance to fix any issues.