Server has dependency of original base image used to Create Server or Rebuild Server. If original image is deleted from glance, nova has server.image.id reference to non-existent image. Rescue in stable device rescue mode leads to driver error and Server in ERROR state.
Step to reproduce:
1. Create server from glance image.
2. Delete original glance image.
3. Run rescue server with input parameter of rescue image CD with hw_rescue_device and hw_rescue_bus image properties defined.
Second use case:
1. Restore Server from backup (with server Rebuild)
2. Delete backup image.
3. Run rescue in stable device mode.
Result: Instance 73706a9a-e976-4024-8068-c439404ec953 cannot be rescued: Driver Error: Image be0e302d-79bd-44e1-93a5-68661e93b43a could not be found.
Result2: VM in ERROR state.
Expected: VM returned to original state, or in shutdown state.
Expected2: I see no reason to keep dependency from original image for any operation with server. I tested all other operations with server, and they all were succesful, even if base image deleted. Libvirt driver code shows that rescue mode use only 1 property from image_meta to determine bus type for device attached. So I see no reason to raise exception if image_meta data if empty.
Stack trace for openstack ZED:
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [None req-6611c9f1-63f1-497a-a1bc-51e770d2df09 a27cbf048299483592d84f13e9fe9797 b7df78883aad4ef7ba0a2778c7741462 - - 8a096fed8060480f8f906f57fca19780 8a096fed8060480f8f906f57fca19780] [instance: 73706a9a-e976-4024-8068-c439404ec953] Error trying to Rescue Instance: nova.exception.ImageNotFound: Image be0e302d-79bd-44e1-93a5-68661e93b43a could not be found.
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] Traceback (most recent call last):
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] File "/usr/lib/python3/dist-packages/nova/image/glance.py", line 285, in show
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] image = self._client.call(context, 2, 'get', args=(image_id,))
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] File "/usr/lib/python3/dist-packages/nova/image/glance.py", line 191, in call
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] result = getattr(controller, method)(*args, **kwargs)
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] File "/usr/lib/python3/dist-packages/glanceclient/v2/images.py", line 197, in get
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] return self._get(image_id)
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] File "/usr/lib/python3/dist-packages/glanceclient/common/utils.py", line 670, in inner
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] return RequestIdProxy(wrapped(*args, **kwargs))
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] File "/usr/lib/python3/dist-packages/glanceclient/v2/images.py", line 190, in _get
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] resp, body = self.http_client.get(url, headers=header)
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] File "/usr/lib/python3/dist-packages/keystoneauth1/adapter.py", line 395, in get
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] return self.request(url, 'GET', **kwargs)
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] File "/usr/lib/python3/dist-packages/glanceclient/common/http.py", line 380, in request
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] return self._handle_response(resp)
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] File "/usr/lib/python3/dist-packages/glanceclient/common/http.py", line 120, in _handle_response
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] raise exc.from_response(resp, resp.content)
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] glanceclient.exc.HTTPNotFound: HTTP 404 Not Found: No image found with ID be0e302d-79bd-44e1-93a5-68661e93b43a
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953]
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] During handling of the above exception, another exception occurred:
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953]
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] Traceback (most recent call last):
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] File "/usr/lib/python3/dist-packages/nova/compute/manager.py", line 4485, in rescue_instance
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] self.driver.rescue(context, instance, network_info,
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] File "/usr/lib/python3/dist-packages/nova/virt/libvirt/driver.py", line 4249, in rescue
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] image_meta = objects.ImageMeta.from_image_ref(
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] File "/usr/lib/python3/dist-packages/nova/objects/image_meta.py", line 151, in from_image_ref
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] image_meta = image_api.get(context, image_ref)
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] File "/usr/lib/python3/dist-packages/nova/image/glance.py", line 1205, in get
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] return session.show(context, image_id,
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] File "/usr/lib/python3/dist-packages/nova/image/glance.py", line 287, in show
2023-01-11 07:33:28.761 1207602 ERROR nova.compute.manager [instance: 73706a9a-e976-4024-8068-c439404ec953] _reraise_translated_image_exception(image_id)
This seems to be valid bug exist on master too. At [1] the driver looks up the original image to get the image_metadata but I think we are stashing that in the instance already so instance.image_meta could be used. But we need to make sure that instance.image_meta is not updated before this point to the rescue image's metadata.
Making this as VALID. Feel free to propose patch to fix this.
https:/