Comment 17 for bug 1607808

As far as I recall, 'Create volume and boot instance from it' pretty frequently failed on instance deletion if the test is run after RabbitMQ failover. I mean, that happened pretty frequently on custom destructive tests for me in previous releases (7.0, 8.0).

The reason is that after RabbitMQ failover OpenStack needs a 'warm-up' load to clean broken connections. Until that load passes, OpenStack lags a little as it clears broken connections and establishes new one on the fly. So either the failed test serves as a 'warm-up' for later tests (the test comes first in the list). Or it just executes almost hitting the limit under normal conditions and lags beyond the limit after failover.