Apache ActiveMQ Artemis has an extensive management API that allows a user to modify a server configuration, create new resources (e.g. addresses and queues), inspect these resources (e.g. how many messages are currently held in a queue) and interact with it (e.g. to remove messages from a queue). Apache ActiveMQ Artemis also allows clients to subscribe to management notifications.

There are numerous ways to access Apache ActiveMQ Artemis management API:

  • Using JMX — JMX is the standard way to manage Java applications

  • Using Jolokia — Jolokia exposes the JMX API of an application through an HTTP interface

  • Using the Core Client — management operations are sent to Apache ActiveMQ Artemis server using Core Client messages

  • Using any JMS Client — management operations are sent to Apache ActiveMQ Artemis server using JMS Client messages

  • Web Console — a web application which provides a graphical interface to the management API.

Although there are four different ways to manage Apache ActiveMQ Artemis, each API supports the same functionality. If it is possible to manage a resource using JMX it is also possible to achieve the same result using Core messages.

Besides these four management interfaces, a Web Console and a Command Line management utility are also available to administrators of ActiveMQ Artemis.

The choice depends on your requirements, your application settings, and your environment to decide which way suits you best.

1. The Management API

Regardless of the way you invoke management operations, the management API is the same.

For each managed resource, there exists a Java interface describing what operations can be invoked for this type of resource.

To learn about available management operations, see the Javadoc for these interfaces. They are located in the org.apache.activemq.artemis.api.core.management package and they are named with the word Control at the end.

1.1. Server Management

The ActiveMQServerControl interface is the entry point for broker management.

  • Listing, creating, deploying and destroying queues

    A list of deployed queues can be retrieved using the getQueueNames() method.

    Queues can be created or destroyed using the management operations createQueue() or deployQueue() or destroyQueue().

    createQueue will fail if the queue already exists while deployQueue will do nothing.

  • Listing and closing remote connections

    Client’s remote addresses can be retrieved using listRemoteAddresses(). It is also possible to close the connections associated with a remote address using the closeConnectionsForAddress() method.

    Alternatively, connection IDs can be listed using listConnectionIDs() and all the sessions for a given connection ID can be listed using listSessions().

  • Transaction heuristic operations

    In case of a server crash, when the server restarts, it possible that some transaction requires manual intervention. The listPreparedTransactions() method lists the transactions which are in the prepared states (the transactions are represented as opaque Base64 Strings.) To commit or rollback a given prepared transaction, the commitPreparedTransaction() or rollbackPreparedTransaction() method can be used to resolve heuristic transactions. Heuristically completed transactions can be listed using the listHeuristicCommittedTransactions() and listHeuristicRolledBackTransactions methods.

  • Enabling and resetting Message counters

    Message counters can be enabled or disabled using the enableMessageCounters() or disableMessageCounters() method. To reset message counters, it is possible to invoke resetAllMessageCounters() and resetAllMessageCounterHistories() methods.

  • Retrieving the server configuration and attributes

    The ActiveMQServerControl exposes Apache ActiveMQ Artemis server configuration through all its attributes (e.g. getVersion() method to retrieve the server’s version, etc.)

  • Listing, creating and destroying Core bridges and diverts

    A list of deployed core bridges (resp. diverts) can be retrieved using the getBridgeNames() (resp. getDivertNames()) method.

    Core bridges (resp. diverts) can be created or destroyed using the management operations createBridge() and destroyBridge() (resp. createDivert() and destroyDivert()).

    Diverts can be updated using the management operation updateDivert().

  • It is possible to stop the server and force failover to occur with any currently attached clients.

    To do this use the forceFailover() operation.

    Since this method actually stops the server you will probably receive some sort of error depending on which management service you use to call it.

1.2. Address Management

Individual addresses can be managed using the AddressControl interface.

  • Modifying roles and permissions for an address

    You can add or remove roles associated to a queue using the addRole() or removeRole() methods. You can list all the roles associated to the queue with the getRoles() method

  • Pausing and resuming an Address

    The AddressControl can pause and resume an address and all the queues that are bound to it. Newly added queue will be paused too until the address is resumed. Thus all messages sent to the address will be received but not delivered. When it is resumed, delivering will occur again.

  • Blocking and un blocking an Address

    The AddressControl can block and unblock an address. A blocked address will not issue any more credit to existing producers. New producers will not be granted any credit. When the address is unblocked, credit granting will resume. In this way, it is possible to drain all the queues associated with an address to quiesce a broker in a managed way.

1.3. Queue Management

The bulk of the management API deals with queues. The QueueControl interface defines the queue management operations.

Most of the management operations on queues take either a single message ID (e.g. to remove a single message) or a filter (e.g. to expire all messages with a given property.)

Passing null or an empty string in the filter parameter means that the management operation will be performed on all messages in a queue.

  • Expiring, sending to a dead letter address and moving messages

    Messages can be expired from a queue by using the expireMessages() method. If an expiry address is defined, messages will be sent to it, otherwise they are discarded.

    Messages can also be sent to a dead letter address with the sendMessagesToDeadLetterAddress() method. It returns the number of messages which are sent to the dead letter address. If a dead letter address is not defined, message are removed from the queue and discarded.

    Messages can also be moved from a queue to another queue by using the moveMessages() method.

  • Listing and removing messages

    Messages can be listed from a queue by using the listMessages() method which returns an array of Map, one Map for each message.

    Messages can also be removed from the queue by using the removeMessages() method which returns a boolean for the single message ID variant or the number of removed messages for the filter variant. The removeMessages() method takes a filter argument to remove only filtered messages. Setting the filter to an empty string will in effect remove all messages.

  • Counting messages

    The number of messages in a queue is returned by the getMessageCount() method. Alternatively, the countMessages() will return the number of messages in the queue which match a given filter.

  • Changing message priority

    The message priority can be changed by using the changeMessagesPriority() method which returns a boolean for the single message ID variant or the number of updated messages for the filter variant.

  • Message counters

    Message counters can be listed for a queue with the listMessageCounter() and listMessageCounterHistory() methods (see Message Counters section). The message counters can also be reset for a single queue using the resetMessageCounter() method.

  • Retrieving the queue attributes

    The QueueControl exposes queue settings through its attributes (e.g. getFilter() to retrieve the queue’s filter if it was created with one, isDurable() to know whether the queue is durable or not, etc.)

  • Pausing and resuming Queues

    The QueueControl can pause and resume the underlying queue. When a queue is paused, it will receive messages but will not deliver them. When it’s resumed, it’ll begin delivering the queued messages, if any.

  • Disabling and Enabling Queues

    The QueueControl can disable and enable the underlying queue. When a queue is disabled, it will not longer have messages routed to it. When it’s enabled, it’ll begin having messages routed to it again.

    This is useful where you may need to disable message routing to a queue but wish to keep consumers active to investigate issues, without causing further message build up in the queue.

1.4. Other Resources Management

Apache ActiveMQ Artemis allows to start and stop its remote resources (acceptors, diverts, bridges, etc.) so that a server can be taken off line for a given period of time without stopping it completely (e.g. if other management operations must be performed such as resolving heuristic transactions). These resources are:

  • Acceptors

    They can be started or stopped using the start() or. stop() method on the AcceptorControl interface. The acceptors parameters can be retrieved using the AcceptorControl attributes (see Understanding Acceptors)

  • Diverts

    They can be started or stopped using the start() or stop() method on the DivertControl interface. Diverts parameters can be retrieved using the DivertControl attributes (see Diverting and Splitting Message Flows)

  • Bridges

    They can be started or stopped using the start() (resp. stop()) method on the BridgeControl interface. Bridges parameters can be retrieved using the BridgeControl attributes (see Core bridges)

  • Broadcast groups

    They can be started or stopped using the start() or stop() method on the BroadcastGroupControl interface. Broadcast groups parameters can be retrieved using the BroadcastGroupControl attributes (see Clusters)

  • Cluster connections

    They can be started or stopped using the start() or stop() method on the ClusterConnectionControl interface. Cluster connections parameters can be retrieved using the ClusterConnectionControl attributes (see Clusters)

2. Management Via JMX

Apache ActiveMQ Artemis can be managed using JMX.

The management API is exposed by Apache ActiveMQ Artemis using MBeans. By default, Apache ActiveMQ Artemis registers its resources with the domain org.apache.activemq.artemis. For example, the ObjectName to manage the anycast queue exampleQueue on the address exampleAddress is:

  1. org.apache.activemq.artemis:broker=<brokerName>,component=addresses,address="exampleAddress",subcomponent=queues,routing-type="anycast",queue="exampleQueue"

and the MBean is:

  1. org.apache.activemq.artemis.api.core.management.QueueControl

The MBean’s ObjectName is built using the helper class org.apache.activemq.artemis.api.core.management.ObjectNameBuilder. Example usage of the ObjectNameBuilder to obtain ActiveMQServerControl‘s name:

  1. brokerName = "0.0.0.0";  // configured e.g. in broker.xml <broker-name> element
  2. objectNameBuilder = ObjectNameBuilder.create(ArtemisResolver.DEFAULT_DOMAIN, brokerName, true);
  3. serverObjectName = objectNameBuilder.getActiveMQServerObjectName()

Managing Apache ActiveMQ Artemis using JMX is identical to management of any Java Applications using JMX. It can be done by reflection or by creating proxies of the MBeans.

2.1. Configuring JMX

By default, JMX is enabled to manage Apache ActiveMQ Artemis. It can be disabled by setting jmx-management-enabled to false in broker.xml:

  1. <jmx-management-enabled>false</jmx-management-enabled>

2.1.1. Role Based Authorisation for JMX

Artemis uses the Java Virtual Machine’s Platform MBeanServer by default. This is guarded using role based authorisation that leverages the broker’s JAAS plugin support.

The RBAC used to restrict access to Mbeans and their operations can be configured in one of two ways. Via security-settings in broker.xml, described in JMX authorization in broker.xml, or via the authorization element in the management.xml that is described below.

JMX authorisation in management.xml

There are 3 elements within the authorisation element, allowlist, default-access and role-access. Let’s discuss each in turn.

Allowlist contains a list of MBeans that will bypass the authorisation, this is typically used for any MBeans that are needed by the console to run etc. The default configuration is:

  1. <allowlist>
  2.    <entry domain="hawtio"/>
  3. </allowlist>

This means that any MBean with the domain hawtio will be allowed access without authorisation. for instance hawtio:plugin=artemis. You can also use wildcards for the MBean properties so the following would also match.

  1. <allowlist>
  2.    <entry domain="hawtio" key="type=*"/>
  3. </allowlist>

The allowlist element has replaced the whitelist element which is now deprecated

The role-access defines how roles are mapped to particular MBeans and its attributes and methods. The default configuration looks like:

  1. <role-access>
  2.   <match domain="org.apache.activemq.artemis">
  3.      <access method="list*" roles="view,update,amq"/>
  4.      <access method="get*" roles="view,update,amq"/>
  5.      <access method="is*" roles="view,update,amq"/>
  6.      <access method="set*" roles="update,amq"/>
  7.      <access method="*" roles="amq"/>
  8.   </match>
  9. </role-access>

This contains 1 match and will be applied to any MBean that has the domain org.apache.activemq.artemis. Any access to any MBeans that have this domain are controlled by the access elements which contain a method and a set of roles. The method being invoked will be used to pick the closest matching method and the roles for this will be applied for access. For instance if you try to invoke a method called listMessages on an MBean with the org.apache.activemq.artemis domain then this would match the access with the method of list*. You could also explicitly configure this by using the full method name, like so:

  1. <access method="listMessages" roles="view,update,amq"/>

You can also match specific MBeans within a domain by adding a key attribute that is used to match one of the properties on the MBean, like:

  1. <match domain="org.apache.activemq.artemis" key="subcomponent=queues">
  2.    <access method="list*" roles="view,update,amq"/>
  3.    <access method="get*" roles="view,update,amq"/>
  4.    <access method="is*" roles="view,update,amq"/>
  5.    <access method="set*" roles="update,amq"/>
  6.    <access method="*" roles="amq"/>
  7. </match>

You could also match a specific queue for instance:

  1. org.apache.activemq.artemis:broker=<brokerName>,component=addresses,address="exampleAddress",subcomponent=queues,routing-type="anycast",queue="exampleQueue"

by configuring:

  1. <match domain="org.apache.activemq.artemis" key="queue=exampleQueue">
  2.    <access method="list*" roles="view,update,amq"/>
  3.    <access method="get*" roles="view,update,amq"/>
  4.    <access method="is*" roles="view,update,amq"/>
  5.    <access method="set*" roles="update,amq"/>
  6.    <access method="*" roles="amq"/>
  7. </match>

You can also use wildcards for the MBean properties so the following would also match, allowing prefix match for the MBean properties.

  1. <match domain="org.apache.activemq.artemis" key="queue=example*">
  2.    <access method="list*" roles="view,update,amq"/>
  3.    <access method="get*" roles="view,update,amq"/>
  4.    <access method="is*" roles="view,update,amq"/>
  5.    <access method="set*" roles="update,amq"/>
  6.    <access method="*" roles="amq"/>
  7. </match>

In case of multiple matches, the exact matches have higher priority than the wildcard matches and the longer wildcard matches have higher priority than the shorter wildcard matches.

Access to JMX MBean attributes are converted to method calls so these are controlled via the set*, get* and is*. The * access is the catch-all for everything other method that isn’t specifically matched.

The default-access element is basically the catch-all for every method call that isn’t handled via the role-access configuration. This has the same semantics as a match element.

2.1.2. JMX authorization in broker.xml

The existing security-settings in broker.xml can be used for JMX RBAC.

Using the view and edit permissions on matches in security-settings provides an alternative to the authorization section in management.xml. Using a single security model based on addresses, with reloadable configuration, simplifies operation.

An MBeanServer interceptor that delegates to the broker security manager must be configured with a JVM system property that allows it to be added to all MBeanServers in the JVM.

This is configured via a system property as follows:

  1.  java -Djavax.management.builder.initial=org.apache.activemq.artemis.core.server.management.ArtemisRbacMBeanServerBuilder
When this property is provided, the authorization section of management.xml MUST be omitted/removed as that depends on an alternative MBeanServer interceptor and builder.

The security-settings match addresses used for JMX RBAC use the mops. (shorthand for management operations) prefix.

The MBeanServer guard maps JMX MBean ObjectNames to a hierarchical address of the general form:

  1. mops<.jmx domain><.type><.component><.name>[.operation]
for the broker domain, the domain is omitted.

For example, to give the admin role view and edit permissions on all MBeans, use the following security-setting:

  1. <security-setting match="mops.#">
  2.    <permission type="view" roles="admin"/>
  3.    <permission type="edit" roles="admin"/>
  4. </security-setting>

To grant the managerRole role view permission to just the activemq.management address, target the address component with name activemq.management and with .* to include all operations.

  1. <security-setting match="mops.address.activemq.management.*">
  2.    <permission type="view" roles="managerRole"/>
  3. </security-setting>

To ensure no user has permission to force a failover using the broker (server control) MBean, use the following that defines the empty roles set for a particular mutating operation on the broker component:

  1. <security-setting match="mops.broker.forceFailover">
  2.    <permission type="edit" roles=""/>
  3. </security-setting>

2.1.3. Local JMX Access with JConsole

Due to the authorisation which is enabled by default Apache ActiveMQ Artemis can not be managed locally using JConsole when connecting as a local process. This is because JConsole does not pass any authentication information when connecting this way which means the user cannot therefore be authorised for any management operations. In order to use JConsole the user will either have to disable authorisation by completely removing the authorisation element from management.xml or by enabling remote access and providing the proper username and password credentials (discussed next).

2.1.4. Remote JMX Access

By default, remote JMX access to Artemis is disabled for security reasons.

Artemis has a JMX agent which allows access to JMX MBeans remotely. This is configured via the connector element in the management.xml configuration file. To enable this you simply add the following xml:

  1. <connector connector-port="1099"/>

This exposes the agent remotely on the port 1099. If you were connecting via JConsole you would connect as a remote process using the service url:

  1. service:jmx:rmi:///jndi/rmi://localhost:1099/jmxrmi

You’d be able to supply an appropriate user name and password in this case as well.

You can also configure the connector using the following:

connector-host

The host to expose the agent on.

connector-port

The port to expose the agent on.

rmi-registry-port

The port that the RMI registry binds to. If not set, the port is always random. Set to avoid problems with remote JMX connections tunnelled through firewall.

jmx-realm

The jmx realm to use for authentication, defaults to activemq to match the JAAS configuration.

object-name

The object name to expose the remote connector on; default is connector:name=rmi.

secured

Whether the connector is secured using SSL.

key-store-path

The location of the keystore.

key-store-password

The keystore password. This can be masked.

key-store-provider

The provider; JKS by default.

trust-store-path

The location of the truststore.

trust-store-password

The trustore password. This can be masked.

trust-store-provider

The provider; JKS by default.

password-codec

The fully qualified class name of the password codec to use. See the password masking documentation for more details on how this works.

It is important to note that the rmi registry will pick an ip address to bind to, If you have a multi IP addresses/NICs present on the system then you can choose the ip address to use by adding the following to artemis.profile -Djava.rmi.server.hostname=localhost

Remote connections using the default JVM Agent not enabled by default as Artemis exposes the MBean Server via its own configuration. This is so Artemis can leverage the JAAS authentication layer via JMX. If you want to expose this then you will need to disable both the connector and the authorisation by removing them from the management.xml configuration. Please refer to Java Management guide to configure the server for remote management (system properties must be set in artemis.profile).

By default, Apache ActiveMQ Artemis server uses the JMX domain “org.apache.activemq.artemis”. To manage several Apache ActiveMQ Artemis servers from the same MBeanServer, the JMX domain can be configured for each individual Apache ActiveMQ Artemis server by setting jmx-domain in broker.xml:

  1. <!-- use a specific JMX domain for ActiveMQ Artemis MBeans -->
  2. <jmx-domain>my.org.apache.activemq</jmx-domain>

2.2. Example

See the JMX Management Example which shows how to use a remote connection to JMX and MBean proxies to manage Apache ActiveMQ Artemis.

2.3. Exposing JMX using Jolokia

The default Broker configuration ships with the Jolokia HTTP agent deployed as a web application. Jolokia is a remote JMX-over-HTTP bridge that exposes MBeans. For a full guide as to how to use it refer to Jolokia Documentation, however a simple example to query the broker’s version would be to use a curl command like this:

  1. $ curl -v -H "Origin: http://localhost" -u myUser:myPass http://localhost:8161/console/jolokia/read/org.apache.activemq.artemis:broker=\"0.0.0.0\"/Active

Or you could send a JSON formatted request instead of using the URL

  1. $ curl -v -H "Origin: http://localhost" -u myUser:myPass --header "Content-type: application/json" --request POST --data '{"attribute": "Active", "mbean": "org.apache.activemq.artemis:broker=\"0.0.0.0\"", "type": "read"}' http://localhost:8161/console/jolokia

By default it’s necessary to pass the Origin header due to the CORS checking which is configured in etc/jolokia-access.xml.

Such a curl command would give you back something like the following (after formatting):

  1. {
  2.   "request": {
  3.     "mbean": "org.apache.activemq.artemis:broker=\"0.0.0.0\"",
  4.     "attribute": "Version",
  5.     "type": "read"
  6.   },
  7.   "value": "2.24.0",
  8.   "timestamp": 1663086398,
  9.   "status": 200
  10. }

2.4. JMX and the Web Console

The web console that ships with Artemis uses Jolokia under the covers which in turn uses JMX. This will use the authentication configuration as described in the Role Based Authorisation for JMX section. This means that when MBeans are accessed via the console the credentials used to log into the console and the roles associated with them. By default, access to the console is only allow via users with the amq role. This is configured in the artemis.profile via the system property -Dhawtio.role=amq. You can configure multiple roles by changing this to -Dhawtio.roles=amq,view,update.

If a user doesn’t have the correct role to invoke a specific operation then this will display an authorisation exception in the console.

2.4.1. ArtemisRbacMBeanServerBuilder and ArtemisRbacInvocationHandler

The ArtemisRbacMBeanServerBuilder class, when configured as value for the system property javax.management.builder.initial will cause the ArtemisRbacInvocationHandler to be installed on every JMX MBeanServer in the JVM. The ArtemisRbacInvocationHandler intercepts all operations on the MBeanServer and chooses to guard a subsection of those operations.

For guarded operations the view or edit permissions are required to make an invocation. If the current authenticated subject does not have the required roles to grant those permissions, a security exception is thrown.

For query operations on the MBeanServer, the results of the query are limited to entries that have the required view permission.

3. Using Management Message API

The management message API in ActiveMQ Artemis is accessed by sending Core Client messages to a special address, the management address.

Management messages are regular Core Client messages with well-known properties that the server needs to understand to interact with the management API:

  • The name of the managed resource

  • The name of the management operation

  • The parameters of the management operation

When such a management message is sent to the management address, Apache ActiveMQ Artemis server will handle it, extract the information, invoke the operation on the managed resources and send a management reply to the management message’s reply-to address (specified by ClientMessageImpl.REPLYTO_HEADER_NAME).

A ClientConsumer can be used to consume the management reply and retrieve the result of the operation (if any) stored in the reply’s body. For portability, results are returned as a JSON String rather than Java Serialization (the org.apache.activemq.artemis.api.core.management.ManagementHelper can be used to convert the JSON string to Java objects).

These steps can be simplified to make it easier to invoke management operations using Core messages:

  1. Create a ClientRequestor to send messages to the management address and receive replies

  2. Create a ClientMessage

  3. Use the helper class org.apache.activemq.artemis.api.core.management.ManagementHelper to fill the message with the management properties

  4. Send the message using the ClientRequestor

  5. Use the helper class org.apache.activemq.artemis.api.core.management.ManagementHelper to retrieve the operation result from the management reply.

For example, to find out the number of messages in the queue exampleQueue:

  1. ClientSession session = ...
  2. ClientRequestor requestor = new ClientRequestor(session, "activemq.management");
  3. ClientMessage message = session.createMessage(false);
  4. ManagementHelper.putAttribute(message, "queue.exampleQueue", "messageCount");
  5. session.start();
  6. ClientMessage reply = requestor.request(m);
  7. int count = (Integer) ManagementHelper.getResult(reply);
  8. System.out.println("There are " + count + " messages in exampleQueue");

Management operation name and parameters must conform to the Java interfaces defined in the management packages.

Names of the resources are built using the helper class org.apache.activemq.artemis.api.core.management.ResourceNames and are straightforward (e.g. queue.exampleQueue for QueueControl of the Queue exampleQueue, or broker for the ActiveMQServerControl).

The ManagementHelper class can be used only with Core JMS messages. When called with a message from a different JMS library, an exception will be thrown.

3.1. Configuring Management

The management address to send management messages is configured in broker.xml:

  1. <management-address>activemq.management</management-address>

By default, the address is activemq.management.

The management address requires a special user permission manage to be able to receive and handle management messages. This is also configured in broker.xml:

  1. <!-- users with the admin role will be allowed to manage -->
  2. <!-- Apache ActiveMQ Artemis using management messages    -->
  3. <security-setting match="activemq.management">
  4.    <permission type="manage" roles="admin" />
  5. </security-setting>

3.2. Fine grained RBAC on management messages

There is optional RBAC on the content of management messages sent to the management address. RBAC is enabled through configuration by setting the attribute management-message-rbac to true.

The manage permission is required to execute management operations via messages. The view and edit permissions must be used in conjunction with the manage permission.

When enabled, more fine-grained permissions on the content of management messages sent to the management address can be configured through the security-settings.

The security-settings match addresses used for RBAC follow the general hierarchical form of: management-rbac-prefix, component type, component name, operation. Where the values are extracted from the management message headers.

  1. <management-rbac-prefix>.<resource type>.<resource name>.<operation>

Immutable operations and attribute access will require the view permission, all other operations will require the edit permission.

In the following example the dataImport role can only access the id attribute of queues, which is the only management operation that is required by the data import command line tool.

  1. <security-setting match="mops.queue.*.getID">
  2.    <permission type="view" roles="dataImport" />
  3.    <permission type="manage" roles="dataImport" />
  4. </security-setting>

If you want the admin role to have full access, use a wildcard after the management-rbac-prefix and grant both the view and edit permissions:

  1. <security-setting match="mops.#">
  2.    <permission type="view" roles="admin" />
  3.    <permission type="update" roles="admin" />
  4.    <permission type="manage" roles="admin" />
  5. </security-setting>

3.3. Management Example

See the Management Example which shows how to use JMS messages to manage the Apache ActiveMQ Artemis server.

4. Management Notifications

Apache ActiveMQ Artemis emits notifications to inform listeners of potentially interesting events (creation of new resources, security violation, etc.).

These notifications can be received by two different ways:

  • JMX notifications

  • Notification messages

4.1. JMX Notifications

If JMX is enabled (see Configuring JMX section), JMX notifications can be received by subscribing to org.apache.activemq.artemis:type=Broker,brokerName=<broker name>,module=Core,serviceType=Server for notifications on resources.

4.2. Notification Messages

Apache ActiveMQ Artemis defines a special management notification address. Queues can be bound to this address so that clients will receive management notifications as messages.

A client which wants to receive management notifications must create a queue bound to the management notification address. It can then receive the notifications from its queue.

Notifications messages are regular messages with additional properties corresponding to the notification (its type, when it occurred, the resources which were concerned, etc.).

Since notifications are regular messages, it is possible to use message selectors to filter out notifications and receives only a subset of all the notifications emitted by the server.

4.2.1. Configuring The Management Notification Address

The management notification address to receive management notifications is configured in broker.xml:

  1. <management-notification-address>activemq.notifications</management-notification-address>

By default, the address is activemq.notifications.

4.2.2. Suppressing Session Notifications

Some messaging patterns can generate a lot of SESSION_CREATED and SESSION_CLOSED notifications. In a clustered environment this will come with some computational overhead. If these notifications are not otherwise used they can be disabled through:

  1. <suppress-session-notifications>true</suppress-session-notifications>

The only time these notifications are required is in a cluster with MQTT clients where unique client ID utilization needs to be enforced. Default value is false

4.2.3. Receiving Notification Messages

Apache ActiveMQ Artemis’s Core JMS Client can be used to receive notifications:

  1. Topic notificationsTopic = ActiveMQJMSClient.createTopic("activemq.notifications");
  3. Session session = ...
  4. MessageConsumer notificationConsumer = session.createConsumer(notificationsTopic);
  5. notificationConsumer.setMessageListener(new MessageListener() {
  6.    public void onMessage(Message notif) {
  7.     System.out.println("------------------------");
  8.     System.out.println("Received notification:");
  9.     try {
  10.      Enumeration propertyNames = notif.getPropertyNames();
  11.      while (propertyNames.hasMoreElements()) {
  12.       String propertyName = (String)propertyNames.nextElement();
  13.       System.out.format("  %s: %s\n", propertyName, notif.getObjectProperty(propertyName));
  14.      }
  15.     } catch (JMSException e) {
  16.     }
  17.     System.out.println("------------------------");
  18.    }
  19. });

4.3. Example

See the Management Notification Example which shows how to use a JMS MessageListener to receive management notifications from ActiveMQ Artemis server.

4.4. Notification Types and Headers

Below is a list of all the different kinds of notifications as well as which headers are on the messages. Every notification has a _AMQ_NotifType (value noted in parentheses) and _AMQ_NotifTimestamp header. The timestamp is the un-formatted result of a call to java.lang.System.currentTimeMillis().

BINDING_ADDED (0)

_AMQ_Binding_Type, _AMQ_Address, _AMQ_ClusterName, _AMQ_RoutingName, _AMQ_Binding_ID, _AMQ_Distance, _AMQ_FilterString

BINDING_REMOVED (1)

_AMQ_Address, _AMQ_ClusterName, _AMQ_RoutingName, _AMQ_Binding_ID, _AMQ_Distance, _AMQ_FilterString

CONSUMER_CREATED (2)

_AMQ_Address, _AMQ_ClusterName, _AMQ_RoutingName, _AMQ_Distance, _AMQ_ConsumerCount, _AMQ_User, _AMQ_ValidatedUser, _AMQ_RemoteAddress, _AMQ_SessionName, _AMQ_FilterString, _AMQ_CertSubjectDN

CONSUMER_CLOSED (3)

_AMQ_Address, _AMQ_ClusterName, _AMQ_RoutingName, _AMQ_Distance, _AMQ_ConsumerCount, _AMQ_User, _AMQ_RemoteAddress, _AMQ_SessionName, _AMQ_FilterString

SECURITY_AUTHENTICATION_VIOLATION (6)

_AMQ_User, _AMQ_CertSubjectDN, _AMQ_RemoteAddress

SECURITY_PERMISSION_VIOLATION (7)

_AMQ_Address, _AMQ_CheckType, _AMQ_User

DISCOVERY_GROUP_STARTED (8)

name

DISCOVERY_GROUP_STOPPED (9)

name

BROADCAST_GROUP_STARTED (10)

name

BROADCAST_GROUP_STOPPED (11)

name

BRIDGE_STARTED (12)

name

BRIDGE_STOPPED (13)

name

CLUSTER_CONNECTION_STARTED (14)

name

CLUSTER_CONNECTION_STOPPED (15)

name

ACCEPTOR_STARTED (16)

factory, id

ACCEPTOR_STOPPED (17)

factory, id

PROPOSAL (18)

_JBM_ProposalGroupId, _JBM_ProposalValue, _AMQ_Binding_Type, _AMQ_Address, _AMQ_Distance

PROPOSAL_RESPONSE (19)

_JBM_ProposalGroupId, _JBM_ProposalValue, _JBM_ProposalAltValue, _AMQ_Binding_Type, _AMQ_Address, _AMQ_Distance

CONSUMER_SLOW (21)

_AMQ_Address, _AMQ_ConsumerCount, _AMQ_RemoteAddress, _AMQ_ConnectionName, _AMQ_ConsumerName, _AMQ_SessionName

ADDRESS_ADDED (22)

_AMQ_Address, _AMQ_Routing_Type

ADDRESS_REMOVED (23)

_AMQ_Address, _AMQ_Routing_Type

CONNECTION_CREATED (24)

_AMQ_ConnectionName, _AMQ_RemoteAddress

CONNECTION_DESTROYED (25)

_AMQ_ConnectionName, _AMQ_RemoteAddress

SESSION_CREATED (26)

_AMQ_ConnectionName, _AMQ_User, _AMQ_SessionName

SESSION_CLOSED (27)

_AMQ_ConnectionName, _AMQ_User, _AMQ_SessionName

MESSAGE_DELIVERED (28)

_AMQ_Address, _AMQ_Routing_Type, _AMQ_RoutingName, _AMQ_ConsumerName, _AMQ_Message_ID

MESSAGE_EXPIRED (29)

_AMQ_Address, _AMQ_Routing_Type, _AMQ_RoutingName, _AMQ_ConsumerName, _AMQ_Message_ID

5. Message Counters

Message counters can be used to obtain information on queues over time as Apache ActiveMQ Artemis keeps a history on queue metrics.

They can be used to show trends on queues. For example, using the management API, it would be possible to query the number of messages in a queue at regular interval. However, this would not be enough to know if the queue is used: the number of messages can remain constant because nobody is sending or receiving messages from the queue or because there are as many messages sent to the queue than messages consumed from it. The number of messages in the queue remains the same in both cases but its use is widely different.

Message counters give additional information about the queues:

count

The total number of messages added to the queue since the server was started

countDelta

the number of messages added to the queue since the last message counter update

messageCount

The current number of messages in the queue

messageCountDelta

The overall number of messages added/removed from the queue since the last message counter update. For example, if messageCountDelta is equal to -10 this means that overall 10 messages have been removed from the queue (e.g. 2 messages were added and 12 were removed)

lastAddTimestamp

The timestamp of the last time a message was added to the queue

lastAckTimestamp

The timestamp of the last time a message from the queue was acknowledged

updateTimestamp

The timestamp of the last message counter update

These attributes can be used to determine other meaningful data as well. For example, to know specifically how many messages were consumed from the queue since the last update simply subtract the messageCountDelta from countDelta.

5.1. Configuring Message Counters

By default, message counters are disabled as it might have a small negative effect on memory.

To enable message counters, you can set it to true in broker.xml:

  1. <message-counter-enabled>true</message-counter-enabled>

Message counters keep a history of the queue metrics (10 days by default) and sample all the queues at regular interval (10 seconds by default). If message counters are enabled, these values should be configured to suit your messaging use case in broker.xml:

  1. <!-- keep history for a week -->
  2. <message-counter-max-day-history>7</message-counter-max-day-history>
  3. <!-- sample the queues every minute (60000ms) -->
  4. <message-counter-sample-period>60000</message-counter-sample-period>

Message counters can be retrieved using the Management API. For example, to retrieve message counters on a queue using JMX:

  1. // retrieve a connection to Apache ActiveMQ Artemis's MBeanServer
  2. MBeanServerConnection mbsc = ...
  3. QueueControlMBean queueControl = (QueueControl)MBeanServerInvocationHandler.newProxyInstance(mbsc,
  4.    on,
  5.    QueueControl.class,
  6.    false);
  7. // message counters are retrieved as a JSON String
  8. String counters = queueControl.listMessageCounter();
  9. // use the MessageCounterInfo helper class to manipulate message counters more easily
  10. MessageCounterInfo messageCounter = MessageCounterInfo.fromJSON(counters);
  11. System.out.format("%s message(s) in the queue (since last sample: %s)\n",
  12. messageCounter.getMessageCount(),
  13. messageCounter.getMessageCountDelta());

5.2. Example

See the Message Counter Example which shows how to use message counters to retrieve information on a queue.