Comment 5 for bug 1709739

This is not a bug in Cinder API. It should be fixed in the tempest update_group test. I'll work on a patch. There are two ways to fix this:

1. When the volume is created outside of the group, we should check whether the volume is created on the same backend as the group. If yes, add volume to the group; otherwise don't add it.

2. Create two volumes in the group, first test remove a volume from the group, then test add the volume back to the group. This involves two update_group API calls and makes the test longer. During the review, I was recommended to make one update_group API call to speed up the test.

I'll submit a patch using approach #1.