we're seeing this bringing up a stack of 30 machines. Nothing in -server.log, api-cfn has:
2014-04-14 10:24:25.659 5608 WARNING heat.openstack.common.rpc.amqp [-] _call_waiters: {'6d59b91a13c34f4b8162b396f029fad0': <heat.openstack.common.rpc.amqp.MulticallProxyWaiter object at 0x7f0d82273710>, '767c24691d6944b9b9f0742580e7b6b5': <heat.openstack.common.rpc.amqp.MulticallProxyWaiter object at 0x7f0d8228a710>, '1055cc2049c049e4b5d095d066cc7e38': <heat.openstack.common.rpc.amqp.MulticallProxyWaiter object at 0x7f0d82068a90>, '2983d5b2a5644bf398445da69355c30e': <heat.openstack.common.rpc.amqp.MulticallProxyWaiter object at 0x7f0d8228ced0>, '28083f4fd8324b9693be71c78d8b555a': <heat.openstack.common.rpc.amqp.MulticallProxyWaiter object at 0x7f0d81f6e610>, 'dd5d1108b2434ef791295e7b56c0c34a': <heat.openstack.common.rpc.amqp.MulticallProxyWaiter object at 0x7f0d81c2a1d0>, 'f04465d45957416e92e3d872306fd92c': <heat.openstack.common.rpc.amqp.MulticallProxyWaiter object at 0x7f0d81daa890>, '1032af02237e49239786beaedd9306ce': <heat.openstack.common.rpc.amqp.MulticallProxyWaiter object at 0x7f0d81e32190>, 'abd966cffbd24f3e8b47ef6fd91a35b2': <heat.openstack.common.rpc.amqp.MulticallProxyWaiter object at 0x7f0d81c8d4d0>, '72dcaa030eab4482a30931f7c8240d6b': <heat.openstack.common.rpc.amqp.MulticallProxyWaiter object at 0x7f0d81c38910>, 'b7a9bed3d4f7464aa9f7417e433ff8fa': <heat.openstack.common.rpc.amqp.MulticallProxyWaiter object at 0x7f0d81cd0f90>, 'f19f4da556bf4f68958ab4fbba5f7fa0': <heat.openstack.common.rpc.amqp.MulticallProxyWaiter object at 0x7f0d81f260d0>, '2345700b180e46fea629c44deaab05c4': <heat.openstack.common.rpc.amqp.MulticallProxyWaiter object at 0x7f0d81e7dbd0>, '10b0635721a0404987b6037866aa777d': <heat.openstack.common.rpc.amqp.MulticallProxyWaiter object at 0x7f0d823a4e90>, 'c4e6dea2af154221bdd6690cb3b70896': <heat.openstack.common.rpc.amqp.MulticallProxyWaiter object at 0x7f0d81c6ba10>, '2429128c7c7e4a2ba621207e6ad4502a': <heat.openstack.common.rpc.amqp.MulticallProxyWaiter object at 0x7f0d81bdc4d0>, 'c62f4776976547009ba9aff089e5ab66': <heat.openstack.common.rpc.amqp.MulticallProxyWaiter object at 0x7f0d82126cd0>, '1bb50b1828084e89922b7758d518315b': <heat.openstack.common.rpc.amqp.MulticallProxyWaiter object at 0x7f0d81e59690>}
Not able to assign this bug to myself, but I am working on a fix.