OpenStack uses a message broker to coordinate operations and status information among services. The message broker service typically runs on the controller node. OpenStack supports several message brokers including RabbitMQ, Qpid, and ZeroMQ. However, most distributions that package OpenStack support a particular message broker. This guide covers the RabbitMQ message broker which is supported by each distribution. If you prefer to implement a different message broker, consult the documentation associated with it. RabbitMQ Qpid ZeroMQ # apt-get install rabbitmq-server # yum install rabbitmq-server # zypper install rabbitmq-server Start the message broker service and configure it to start when the system boots: # systemctl enable rabbitmq-server.service # systemctl start rabbitmq-server.service On SLES: # service rabbitmq-server start # chkconfig rabbitmq-server on On openSUSE: # systemctl enable rabbitmq-server.service # systemctl start rabbitmq-server.service The message broker creates a default account that uses guest for the username and password. To simplify installation of your test environment, we recommend that you use this account, but change the password for it. Run the following command: Replace RABBIT_PASS with a suitable password. # rabbitmqctl change_password guest RABBIT_PASS Changing password for user "guest" ... ...done. You must configure the rabbit_password key in the configuration file for each OpenStack service that uses the message broker. For production environments, you should create a unique account with suitable password. For more information on securing the message broker, see the documentation. If you decide to create a unique account with suitable password for your test environment, you must configure the rabbit_userid and rabbit_password keys in the configuration file of each OpenStack service that uses the message broker. Congratulations, now you are ready to install OpenStack services!