At least one controller is required to redeploy environment

[Julia Aranovich]

Deploy multi-node env, then mark controller as 'pending deletion'. Add new controller and deploy environment. There will be an error (see an attached screenshot): "Not enough deployed controllers - deployed cluster requires at least 1 deployed controller."

From my point of view this message should appear in Deploy Changes dialog and block redeployment (lock Deploy button) as we do for 'New' environments.

[Przemyslaw Kaminski (pkaminski)]

The above messages are moved to 'limits' object in this review request: https://review.openstack.org/#/c/126930/

Unfortunately the situation you describe here is not covered by that request. Let me explain: all limits are checked assuming deployment is successful. I.e. for controller we have min: 1. So in new cluster we add new controller and so number of controllers with pending_addition is 1. The limit checker is happy because this is correct -- after successful deployment there will be 1 controller.

What you describe is to check 'worst case' limits, i.e. that for some time during deployment there will be no controller at all. But when deploying new cluster there is also such situation: for some time there is no controller at all but the deployment procedure is correct!

The solution I see is to modify limit checking code so that it counts number of nodes differently for fresh cluster and for a redeployed one. If you have other suggestions then please share :)

[Vitaly Kramskikh (vkramskikh)]

I think we could add a new key (cannot come up with a proper name, maybe "absolute_min") and set it to 1 for controllers and handle it properly.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Julia Aranovich (<email address hidden>) on branch: master
Review: https://review.openstack.org/257720
Reason: Postponed to 9.0

[Julia Aranovich (jkirnosova)]

Now Nailgun doesn't block deployment without controllers. The issue becomes not actual.