Hello, We are attempting to use Heat stacks with wait conditions with nested stacks. We have a test stack similar to this one https://github.com/openstack/heat-templates/tree/master/hot/autohealing where we are scaling a template. We are testing with the proposed fix in the link below. https://review.opendev.org/c/openstack/heat/+/915209/2/heat/engine/resources... Problem being faced is when updating the heat stack, all of the resources are replaced. This is not ideal as we would like the server resources to update with rolling updates. The rolling updates do take place as described in the auto-scaling group, but only after all resources are replaced. Seems the _needs_update call for the wait handle is triggering a replaced for all resources in the nested stack which is not the desired outcome. 2024-04-19 18:12:03Z [stack_1-j190L]: UPDATE_IN_PROGRESS Stack UPDATE started 2024-04-19 18:12:03Z [stack_1-j190L.asg]: UPDATE_IN_PROGRESS state changed 2024-04-19 18:12:04Z [stack_1-j190L.asg]: UPDATE_IN_PROGRESS Stack UPDATE started 2024-04-19 18:12:04Z [stack_1-j190L.asg.4s52xugnxsrl]: UPDATE_IN_PROGRESS state changed 2024-04-19 18:12:05Z [stack_1-j190L.asg.fpe6jz2dccpg]: UPDATE_IN_PROGRESS state changed 2024-04-19 18:12:05Z [stack_1-j190L.asg.4s52xugnxsrl]: UPDATE_IN_PROGRESS Stack UPDATE started 2024-04-19 18:12:06Z [stack_1-j190L.asg.4s52xugnxsrl.wait_handle]: CREATE_IN_PROGRESS state changed 2024-04-19 18:12:06Z [stack_1-j190L.asg.o7dhu7neswv4]: UPDATE_IN_PROGRESS state changed 2024-04-19 18:12:06Z [stack_1-j190L.asg.fpe6jz2dccpg]: UPDATE_IN_PROGRESS Stack UPDATE started 2024-04-19 18:12:07Z [stack_1-j190L.asg.4s52xugnxsrl.wait_handle]: CREATE_COMPLETE state changed 2024-04-19 18:12:07Z [stack_1-j190L.asg.fpe6jz2dccpg.wait_handle]: CREATE_IN_PROGRESS state changed 2024-04-19 18:12:07Z [stack_1-j190L.asg.4s52xugnxsrl.instance1]: UPDATE_IN_PROGRESS state changed 2024-04-19 18:12:07Z [stack_1-j190L.asg.4s52xugnxsrl.wait_condition]: UPDATE_IN_PROGRESS state changed 2024-04-19 18:12:07Z [stack_1-j190L.asg.4s52xugnxsrl.wait_condition]: UPDATE_COMPLETE The Resource wait_condition requires replacement. 2024-04-19 18:12:07Z [stack_1-j190L.asg.4s52xugnxsrl.wait_condition]: CREATE_IN_PROGRESS state changed 2024-04-19 18:12:07Z [stack_1-j190L.asg.o7dhu7neswv4]: UPDATE_IN_PROGRESS Stack UPDATE started 2024-04-19 18:12:07Z [stack_1-j190L.asg.fpe6jz2dccpg.wait_handle]: CREATE_COMPLETE state changed 2024-04-19 18:12:08Z [stack_1-j190L.asg.o7dhu7neswv4.wait_handle]: CREATE_IN_PROGRESS state changed 2024-04-19 18:12:08Z [stack_1-j190L.asg.fpe6jz2dccpg.instance1]: UPDATE_IN_PROGRESS state changed 2024-04-19 18:12:08Z [stack_1-j190L.asg.fpe6jz2dccpg.wait_condition]: UPDATE_IN_PROGRESS state changed 2024-04-19 18:12:08Z [stack_1-j190L.asg.fpe6jz2dccpg.wait_condition]: UPDATE_COMPLETE The Resource wait_condition requires replacement. 2024-04-19 18:12:08Z [stack_1-j190L.asg.fpe6jz2dccpg.wait_condition]: CREATE_IN_PROGRESS state changed 2024-04-19 18:12:08Z [stack_1-j190L.asg.o7dhu7neswv4.wait_handle]: CREATE_COMPLETE state changed 2024-04-19 18:12:09Z [stack_1-j190L.asg.o7dhu7neswv4.instance1]: UPDATE_IN_PROGRESS state changed 2024-04-19 18:12:09Z [stack_1-j190L.asg.o7dhu7neswv4.wait_condition]: UPDATE_IN_PROGRESS state changed 2024-04-19 18:12:09Z [stack_1-j190L.asg.o7dhu7neswv4.wait_condition]: UPDATE_COMPLETE The Resource wait_condition requires replacement. 2024-04-19 18:12:09Z [stack_1-j190L.asg.o7dhu7neswv4.wait_condition]: CREATE_IN_PROGRESS state changed 2024-04-19 18:12:11Z [stack_1-j190L.asg.4s52xugnxsrl.instance1]: UPDATE_COMPLETE The Resource Server "instance1" [27bbecab-bca3-48f0-9b1b-75d240d741a4] Stack "stack_1-j190L-asg-fmddtpch4ekg-4s52xugnxsrl-n56r3c5cxvwm" [8c4b9dcb-d4e3-4ff5-a442-c2b4f6302c38] requires replacement. 2024-04-19 18:12:11Z [stack_1-j190L.asg.4s52xugnxsrl.instance1]: CREATE_IN_PROGRESS state changed 2024-04-19 18:12:11Z [stack_1-j190L.asg.fpe6jz2dccpg.instance1]: UPDATE_COMPLETE The Resource Server "instance1" [58cffc7c-9278-43eb-bc36-fbbf9537a580] Stack "stack_1-j190L-asg-fmddtpch4ekg-fpe6jz2dccpg-7ipvlcpw237k" [1fd36182-6ac6-4f7b-aa3c-8ddaac1d933c] requires replacement. 2024-04-19 18:12:11Z [stack_1-j190L.asg.fpe6jz2dccpg.instance1]: CREATE_IN_PROGRESS state changed 2024-04-19 18:12:12Z [stack_1-j190L.asg.o7dhu7neswv4.instance1]: UPDATE_COMPLETE The Resource Server "instance1" [61dbda35-f20e-4018-85ad-66ba2e03c506] Stack "stack_1-j190L-asg-fmddtpch4ekg-o7dhu7neswv4-bqwgkjmslxkq" [c4b73bac-fdc8-4a78-8c18-1963054bc2fe] requires replacement. Regards, Devin