Comment 2 for bug 422433

The problem is that when ec2 test is starting up, it looks for a key pair called 'ec2-test-runner'. If it finds it, it deletes it. Then it creates a key pair with this name and uses it to start an instance. The race occurs when one invocation deletes the key pair after another has created it but before it uses it.

I think a fix would be to instead of deleting an existing key pair, to mutate the key pair name until one can be created, and then deleting it again after the instance is safely booted.