Comment 4 for bug 1366166

The Nova patch is currently -2d and I have a Horizon patch ready for this, so I'm reopening and assigning to myself.

There are 3 issues once this problem occurs:

1. The Instance details page become inaccessible. This is particularly problematic because of the Console tab, as it means end-users cannot access the console anymore
2. The Resize screen doesn't open anymore, so users can't even switch the instance to use another flavor that is accessible to them
3. For operations that requires updates for "in progress" operations, the instance row disappears from the table because of the failure to get the flavor

Even if the Nova patch merges soon, I think the Horizon one remains useful because it lets us handle failures on retrieving flavor information more gracefully. Even if that API call fails and we can't tell what's the size of the instance, we shouldn't bar the user from using the console or accessing other information.

The problem can also be reproduced in Juno and Icehouse.