Chapter 8. Sending Commands to the Broker
Abstract
Red Hat AMQ provides a number of commands that can be used to manage a broker, deploy new brokers, and report administrative details. You can send these commands to a broker using either the broker command console or the administration client.
Overview
The default mode for running a Red Hat AMQ broker is to run in daemon mode. In this mode, the broker runs as a background process and you have no direct means for managing it or requesting status information. You can access a broker in daemon mode in the following ways:
- the AMQ administration client that can be used to send any of the console commands to a broker running in daemon mode
- a broker running in console mode can connect to a remote broker and be used to manage the remote broker
- Red Hat AMQ includes a vanilla Apache Karaf shell that can connect to a remote broker and be used to manage the remote broker
If a broker is started in console mode, you can simply enter commands directly in the command console.
Running the administration client
The AMQ administration client is run using the client in
InstallDir/bin. Example 8.1, “Client Command” shows the syntax for the command.
Example 8.1. Client Command
client [
--help
] [
-a port
] [
-h host
] [
-u user
] [
-p password
] [
-v
] [
-r attempts
] [
-d delay
] [
commands
]
Table 8.1, “Administration Client Arguments” describes the command's arguments.
| Argument | Description |
|---|---|
--help | Displays the help message. |
-a | Specifies the remote host's port. |
-h | Specify the remote host's name. |
-u | Specifies user name used to log into the broker. |
-p | Specifies the password used to log into the broker. |
-v | Use verbose output. |
-r | Specifies the maximum number of attempts to establish a connection. |
-d | Specifies, in seconds, the delay between retries. The default is 2 seconds. |
| commands | Specifies one or more commands to run. If no commands are specified, the client enters an interactive mode. |
Using the broker console
The console provides commands that you can use to perform basic management of your AMQ environment, including managing destinations, connections and other administrative objects in the broker.
The console uses prefixes to group commands relating to the same functionality. For example commands related to configuration are prefixed config:, and logging-related commands are prefixed log:.
The console provides two levels of help:
- console help—list all of the commands along with a brief summary of the commands function
- command help—a detailed description of a command and its arguments
To access the console help you use the help command from the console prompt. It will display a grouped list of all the commands available in the console. Each command in the list will be followed by a description of the command as shown in Example 8.2, “Console Help”.
Example 8.2. Console Help
JBossA-MQ:karaf@root>helpCOMMANDS activemq:browse activemq:bstat activemq:list activemq:purge activemq:query admin:change-opts Changes the Java options of an existing container instance. admin:change-rmi-registry-port Changes the RMI registry port (used by management layer) of an existing container instance....JBossA-MQ:karaf@root>
The help for each command includes the definition, the syntax, and the arguments and any options. To display the help for a command, type the command with the
--help option. As shown in Example 8.3, “Help for a Command”, entering admin:start --help displays the help for that command.
Example 8.3. Help for a Command
JBossA-MQ:karaf@root>admin:start --helpDESCRIPTION admin:start Starts an existing container instance. SYNTAX admin:start [options] name ARGUMENTS name The name of the container instance OPTIONS --help Display this help message -o, --java-opts Java options when launching the instanceJBossA-MQ:karaf@root>
Connecting a console to a remote broker
How you connect a command console to a broker on a remote machine depends on if the brokers are part of the same fabric. If the remote broker you want to command is a part of the same fabric as the broker whose command console you are using, then you can use the fabric:container-connect command to establish a connection to the remote broker.
The fabric:container-connect command has one required argument that specifies the name of the container to which a connection will be opened. You can also specify a command to be executed by the remote console connection. If you do not specify a command, you are presented with a prompt that will pass commands to the remote broker's console..
If you are not using fabric, or the remote broker is not part of the same fabric as the broker whose command console you are using, you create a remote connection using the ssh:ssh command. The ssh:ssh command also only requires a single argument to establish the remote connection. In this case, it is the hostname, or IP address, of the machine on which the broker is running. If the remote broker is not using the default SSH port (8101), you will also need to specify the remote broker's SSH port using the
-p flag. You can also specify a command to be executed by the remote console connection. If you do not specify a command, you are presented with a prompt that will pass commands to the remote broker's console.
To disconnect from the remote console, you use the logout command or press Control+D.
Starting a basic console
Red Hat AMQ includes a shell command that will open a vanilla command console without starting a broker instance. You can use this command console to connect to remote brokers in the same way as you would a broker's command console.
Available commands
The remote client can execute any of the broker's console commands. For a complete list of commands see the [Console Reference].
