If you use Rabbitmq message service in OpenStack, and if you have installed the kilo release, then you probably have seen that every connection is broken between services (nova, neutron...) and RabbitMQ.
AMQP server on controller:5672 is unreachable: [Errno 111] ECONNREFUSED. Trying again in 2 seconds
Indeed, starting from the 3.3.0 version, rabbitmq no longer permit the guest account to be used from a remote location.
All right, so, we need either to change the guest account behavior, or create a new account, with the same privilege as the guest account. I picked up the second solution. Execute these commands on the node where RabbitMQ is running :
Then change in all your OpenStack configuration file (nova.conf, neutron.con, ceilometer.conf etc...) the rabbitmq credentials :
rabbit_userid=fred rabbit_password=changeme