From 4a2c9a4887a219a6d4dfe83c430b040713fc4109 Mon Sep 17 00:00:00 2001 From: Matt Riedemann Date: Mon, 29 Jan 2018 10:50:36 -0500 Subject: [PATCH] Rollback instance.image_ref on failed rebuild When rebuilding and changing the image, we run the new image through the scheduler to see if it's valid for the instance on its current compute host. The API saves off the new image ref on the instance before casting to conductor to run through the scheduler. If the scheduler fails, the instance.image_ref was not being rolled back, which meant a user could attempt the rebuild with the same invalid image a second time and the API, seeing the instance.image_ref hasn't changed (even though it's not the actual backing image for the server), will bypass the scheduler and rebuild the instance with that invalid image. This fixes the issue by using the original image ref, passed from API to conductor during rebuild, to reset the instance.image_ref in the case of a failure. Note that there are other things changed on the instance in the API which this patch does not attempt to recover as that's a bigger work item which likely involves substantial refactoring of the code. Closes-Bug: #1746032 Change-Id: I3399a66fe9b1297cd6b0dca440145393ceaef41f --- nova/conductor/manager.py | 10 ++++++++++ nova/tests/functional/test_servers.py | 21 +++++++++++++++------ 2 files changed, 25 insertions(+), 6 deletions(-) diff --git a/nova/conductor/manager.py b/nova/conductor/manager.py index 6497e0f77e95..a026d36aa483 100644 --- a/nova/conductor/manager.py +++ b/nova/conductor/manager.py @@ -953,6 +953,11 @@ class ComputeTaskManager(base.Base): if migration: migration.status = 'error' migration.save() + # Rollback the image_ref if a new one was provided (this + # only happens in the rebuild case, not evacuate). + if orig_image_ref and orig_image_ref != image_ref: + instance.image_ref = orig_image_ref + instance.save() with excutils.save_and_reraise_exception(): self._set_vm_state_and_notify(context, instance.uuid, 'rebuild_server', @@ -966,6 +971,11 @@ class ComputeTaskManager(base.Base): if migration: migration.status = 'error' migration.save() + # Rollback the image_ref if a new one was provided (this + # only happens in the rebuild case, not evacuate). + if orig_image_ref and orig_image_ref != image_ref: + instance.image_ref = orig_image_ref + instance.save() request_spec = request_spec.to_legacy_request_spec_dict() with excutils.save_and_reraise_exception(): self._set_vm_state_and_notify(context, instance.uuid, diff --git a/nova/tests/functional/test_servers.py b/nova/tests/functional/test_servers.py index eb45ab5a43d9..25ac05df46f1 100644 --- a/nova/tests/functional/test_servers.py +++ b/nova/tests/functional/test_servers.py @@ -1164,11 +1164,12 @@ class ServerRebuildTestCase(integrated_helpers._IntegratedTestBase, self.flags(host='host2') self.compute2 = self.start_service('compute', host='host2') + # We hard-code from a fake image since we can't get images + # via the compute /images proxy API with microversion > 2.35. + original_image_ref = '155d900f-4e14-4e4c-a73d-069cbf4541e6' server_req_body = { 'server': { - # We hard-code from a fake image since we can't get images - # via the compute /images proxy API with microversion > 2.35. - 'imageRef': '155d900f-4e14-4e4c-a73d-069cbf4541e6', + 'imageRef': original_image_ref, 'flavorRef': '1', # m1.tiny from DefaultFlavorsFixture, 'name': 'test_rebuild_with_image_novalidhost', # We don't care about networking for this test. This requires @@ -1211,15 +1212,23 @@ class ServerRebuildTestCase(integrated_helpers._IntegratedTestBase, # Before microversion 2.51 events are only returned for instance # actions if you're an admin. self.api_fixture.admin_api) - # Unfortunately the server's image_ref is updated to be the new image - # even though the rebuild should not work. + # Assert the server image_ref was rolled back on failure. server = self.api.get_server(server['id']) - self.assertEqual(rebuild_image_ref, server['image']['id']) + self.assertEqual(original_image_ref, server['image']['id']) # The server should be in ERROR state self.assertEqual('ERROR', server['status']) self.assertIn('No valid host', server['fault']['message']) + # Rebuild it again with the same bad image to make sure it's rejected + # again. Since we're using CastAsCall here, there is no 202 from the + # API, and the exception from conductor gets passed back through the + # API. + ex = self.assertRaises( + client.OpenStackApiException, self.api.api_post, + '/servers/%s/action' % server['id'], rebuild_req_body) + self.assertIn('NoValidHost', six.text_type(ex)) + def test_rebuild_with_new_image(self): """Rebuilds a server with a different image which will run it through the scheduler to validate the image is still OK with the compute host