This chapter explains how to use the Message Queue Command utility (imqcmd) to manage a broker. The chapter has the following sections:
This chapter does not cover all topics related to managing a broker. Additional topics are covered in the following separate chapters:
For information on configuring and managing connection services, see Chapter 6, Configuring and Managing Connection Services.
For information on managing message delivery services, including how to create, display, update, and destroy physical destinations, see Chapter 7, Managing Message Delivery.
For information on configuring and managing persistence services, for both flat-file and JDBC-based data stores, see Chapter 8, Configuring Persistence Services.
For information about setting up security for the broker, such as user authentication, access control, encryption, and password files, see Chapter 9, Configuring and Managing Security Services.
For information on configuring and managing clustering services, for both conventional and enhanced broker clusters, see Chapter 10, Configuring and Managing Broker Clusters.
For information about monitoring a broker, see Chapter 12, Monitoring Broker Operations.
Before using the Command utility to manage a broker, you must do the following:
Start the broker using the imqbrokerd command. You cannot use the Command utility subcommands l until a broker is running.
Determine whether you want to set up a Message Queue administrative user or use the default account. You must specify a user name and password to use all Command utility subcommands (except to display command help and version information).
When you install Message Queue, a default flat-file user repository is installed. The repository is shipped with two default entries: an administrative user and a guest user. If you are testing Message Queue, you can use the default user name and password (admin/admin) to run the Command utility.
If you are setting up a production system, you must set up authentication and authorization for administrative users. See Chapter 9, Configuring and Managing Security Services for information on setting up a file-based user repository or configuring the use of an LDAP directory server. In a production environment, it is a good security practice to use a nondefault user name and password.
If you want to use a secure connection to the broker, set up and enable the ssladmin service on the target broker instance, For more information, see Message Encryption.
The Message Queue Command utility (imqcmd) enables you to manage the broker and its services interactively from the command line. See Command Utility for general reference information about the syntax, subcommands, and options of the imqcmd command, and Chapter 16, Broker Properties Reference for specific information on the configuration properties used to specify broker behavior.
Because each imqcmd subcommand is authenticated against the user repository, it requires a user name and password. The only exceptions are commands that use the -h or -H option to display help, and those that use the -v option to display the product version.
Use the -u option to specify an administrative user name. For example, the following command displays information about the default broker:
imqcmd query bkr -u admin
If you omit the user name, the command will prompt you for it.
For simplicity, the examples in this chapter use the default user name admin as the argument to the -u option. In a real-life production environment, you would use a custom user name.
Specify the password using one of the following methods:
Create a password file and enter the password into that file as the value of the imq.imqcmd.password property. On the command line, use the -passfile option to provide the name of the password file.
Let the imqcmd command prompt you for the password.
In previous versions of Message Queue, you could use the -p option to specify a password on the imqcmd command line. As of Message Queue 4.0, this option is deprecated and is no longer supported; you must instead use one of the methods listed above.
Most imqcmd subcommands use the -b option to specify the host name and port number of the broker to which the command applies:
If no broker is specified, the command applies by default to a broker running on the local host (localhost) at port number 7676. To issue a command to a broker that is running on a remote host, listening on a nondefault port, or both, you must use the -b option to specify the host and port explicitly.
To display the Message Queue product version, use the -v option. For example:
If you enter an imqcmd command line containing the -v option in addition to a subcommand or other options, the Command utility processes only the -v option. All other items on the command line are ignored.
To display help on the imqcmd command, use the -h or -H option, and do not use a subcommand. You cannot get help about specific subcommands.
For example, the following command displays help about imqcmd:
If you enter an imqcmd command line containing the -h or -H option in addition to a subcommand or other options, the Command utility processes only the -h or -H option. All other items on the command line are ignored.
The examples in this section illustrate how to use the imqcmd command.
The following example lists the properties of the broker running on host localhost at port 7676, so the -b option is unnecessary:
imqcmd query bkr -u admin
The command uses the default administrative user name (admin) and omits the password, so that the command will prompt for it.
The following example lists the properties of the broker running on the host myserver at port 1564. The user name is aladdin:
imqcmd query bkr -b myserver:1564 -u aladdin
(For this command to work, the user repository would need to be updated to add the user name aladdin to the admin group.)
The following example lists the properties of the broker running on localhost at port 7676. The initial timeout for the command is set to 20 seconds and the number of retries after timeout is set to 7. The user’s password is in a password file called myPassfile, located in the current directory at the time the command is invoked.
imqcmd query bkr -u admin -passfile myPassfile -rtm 20 -rtr 7
For a secure connection to the broker, these examples could include the -secure option. This option causes the Command utility to use the ssladmin service if that service has been configured and started.
This section describes how to use Command utility subcommands to perform the following broker management tasks:
In addition to using the subcommands described in the following sections, imqcmd allows you to set system properties using the –D option. This is useful for setting or overriding connection factory properties or connection-related Java system properties.
For example, the following command changes the default value of imqSSLIsHostTrusted:
imqcmd list svc -secure -DimqSSLIsHostTrusted=true
The following command specifies the password file and the password used for the SSL trust store that is used by the imqcmd command:
imqcmd list svc -secure -DJavax.net.ssl.trustStore=/tmp/MyTruststore -Djavax.net.ssl.trustStorePassword=MyTrustword
imqcmd shutdown bkr [-b hostName:portNumber] [-time nSeconds] [-nofailover]
The broker stops accepting new connections and messages, completes delivery of existing messages, and terminates the broker process.
The -time option, if present, specifies the interval, in seconds, to wait before shutting down the broker. For example, the following command delays 90 seconds and then shuts down the broker running on host wolfgang at port 1756:
imqcmd shutdown bkr -b wolfgang:1756 -time 90 -u admin
The broker will not block, but will return immediately from the delayed shutdown request. During the shutdown interval, the broker will not accept any new jms connections; admin connections will be accepted, and existing jms connections will continue to operate. If the broker belongs to an enhanced broker cluster, it will not attempt to take over for any other broker during the shutdown interval.
If the broker is part of an enhanced broker cluster (see High-Availability Clusters in Sun Java System Message Queue 4.3 Technical Overview), another broker in the cluster will ordinarily attempt to take over its persistent data on shutdown; the -nofailover option to the imqcmd shutdown bkr subcommand suppresses this behavior. Conversely, you can use the imqcmd takeover bkr subcommand to force such a takeover manually (for instance, if the takeover broker were to fail before completing the takeover process); see Preventing or Forcing Broker Failover for more information.
The imqcmd takeover bkr subcommand is intended only for use in failed-takeover situations. You should use it only as a last resort, and not as a general way of forcibly taking over a running broker.
imqcmd restart bkr [-b hostName:portNumber]
This shuts down the broker and then restarts it using the same options that were specified when it was first started. To choose different options, shut down the broker with imqcmd shutdown bkr and then start it again with the Broker utility (imqbrokerd), specifying the options you want.
imqcmd quiesce bkr [-b hostName:portNumber]
If the broker is part of an enhanced broker cluster, this allows its operations to wind down normally without triggering a takeover by another broker, for instance in preparation for shutting it down administratively for upgrade or similar purposes. For example, the following command quiesces the broker running on host hastings at port 1066:
imqcmd quiesce bkr -b hastings:1066 -u admin
imqcmd unquiesce bkr [-b hostName:portNumber]
For example, the following command unquiesces the broker that was quiesced in the preceding example:
imqcmd unquiesce bkr -b hastings:1066 -u admin
imqcmd pause bkr [-b hostName:portNumber]
For example, the following command pauses the broker running on host myhost at port 1588:
imqcmd pause bkr -b myhost:1588 -u admin
Because its connection service threads are suspended, a paused broker is unable to accept new connections, receive messages, or dispatch messages. The admin connection service is not suspended, allowing you to continue performing administrative tasks needed to regulate the flow of messages to the broker. Pausing a broker also does not suspend the cluster connection service; however, since message delivery within a cluster depends on the delivery functions performed by the different brokers in the cluster, pausing a broker in a cluster may result in a slowing of some message traffic.
imqcmd resume bkr [-b hostName:portNumber]
For example, the following command resumes the default broker (host localhost at port 7676):
imqcmd resume bkr -u admin
The subcommand imqcmd update bkr can be used to change the values of a subset of broker properties for the default broker (or for the broker at a specified host and port):
imqcmd update bkr [-b hostName:portNumber] -o property1=value1 [ [-o property2=value2] … ]
For example, the following command turns off the auto-creation of queue destinations for the default broker:
imqcmd update bkr -o imq.autocreate.queue=false -u admin
You can use imqcmd update bkr to update any of the following broker properties:
See Chapter 16, Broker Properties Reference for detailed information about these properties.
imqcmd query bkr -b hostName:portNumber
This lists the current settings of the broker’s properties, as shown in Example 5–1.
imqcmd metrics bkr [-b hostName:portNumber] [-m metricType] [-int interval] [-msp numSamples]
The -m option specifies the type of metric information to display:
ttl (default): Messages and packets flowing into and out of the broker
rts: Rate of flow of messages and packets into and out of the broker per second
cxn: Connections, virtual memory heap, and threads
The -int and -msp options specify, respectively, the interval (in seconds) at which to display the metrics and the number of samples to display in the output. The default values are 5 seconds and an unlimited number of samples.
For example, the following command displays the rate of message flow into and out of the default broker (host localhost at port 7676) at 10-second intervals:
imqcmd metrics bkr -m rts -int 10 -u admin
Example 5–2 shows an example of the resulting output.
For a more detailed description of the data gathered and reported by the broker, see Brokerwide Metrics.
For brokers belonging to a broker cluster, the imqcmd list bkr subcommand displays information about the configuration of the cluster; see Displaying a Cluster Configuration for more information.