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 message broker supported by each distribution. If you prefer to implement a different message broker, consult the documentation associated with it. RabbitMQ Qpid ZeroMQ Ubuntu and Debian use RabbitMQ. # apt-get install rabbitmq-server Red Hat Enterprise Linux (RHEL), CentOS, Scientific Linux, and Fedora use Qpid. # yum install qpid-cpp-server SUSE Linux Enterprise Server (SLES) and openSUSE use RabbitMQ. # zypper install rabbitmq-server To simplify installation of your test environment, we recommend that you disable authentication. Edit the /etc/qpidd.conf file and change the following key: auth=no For production environments, you should enable authentication. For more information on securing the message broker, see the documentation. If you decide to enable authentication for your test environment, you must configure the qpid_username and qpid_password keys in the configuration file of each OpenStack service that uses the message broker. Start the message broker service: # service rabbitmq-server start 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 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. Start the message broker service and configure it to start when the system boots: # service qpidd start # chkconfig qpidd on Configure the message broker service to start when the system boots: # chkconfig rabbitmq-server on Congratulations, now you are ready to install OpenStack services!