I don't remember when the change to log attempts to grab locks landed. Maybe your version doesn't have that. In that case, my guess is that it's attempting to grab a lock to fiddle with iptables, but something is already holding that lock. There should be a nova directory in /var/lock. Can you provide an "ls - l" of that dir? -- Soren Hansen | http://linux2go.dk/ Ubuntu Developer | http://www.ubuntu.com/ OpenStack Developer | http://www.openstack.org/