Apache Geode

Starting a JMX Manager

JMX Manager nodes are members that manage other Geode members (as well as themselves). A JMX Manager node can manage all other members in the cluster. Typically a locator will function as the JMX Manager, but you can also turn any other member such as a server into a JMX Manager node as well.

To allow a server to become a JMX Manager you configure Geode property jmx-manager=true, in the server’sgemfire.properties file. This property configures the node to become a JMX Manager node passively; if gfsh cannot locate a JMX Manager when connecting to the cluster, the server node will be started as a JMX Manager node.

Note: The default property setting for all locators is gemfire.jmx-manager=true. For other members, the default property setting is gemfire.jmx-manager=false.

To force a server to become a JMX Manager node whenever it is started, set the Geode properties jmx-manager-start=true and jmx-manager=true in the server’s gemfire.properties file. Note that both of these properties must be set to true for the node.

To start the member as a JMX Manager node on the command line, provide--J=-Dgemfire.jmx-manager-start=true and --J=-Dgemfire.jmx-manager=true as arguments to either the start server or start locator command.

For example, to start a server as a JMX Manager on the gfsh command line:

gfsh>start server --name=<server-name> --J=-Dgemfire.jmx-manager=true \
--J=-Dgemfire.jmx-manager-start=true

By default, any locator can become a JMX Manager when started. When you start up a locator, if no other JMX Manager is detected in the cluster, the locator starts one automatically. If you start a second locator, it will detect the current JMX Manager and will not start up another JMX Manager unless the second locator’s gemfire.jmx-manager-start property is set to true.

For most deployments, you only need to have one JMX Manager per cluster. However, you can run more than one JMX Manager if necessary. If you want to provide high-availability and redundancy for the Pulse monitoring tool, or if you are running additional JMX clients other than gfsh, then use the jmx-manager-start=true property to force individual nodes (either locators or servers) to become JMX Managers at startup. Since there is some performance overhead to being a JMX Manager, we recommend using locators as JMX Managers. If you do not want a locator to become a JMX manager, then you must use the jmx-manager=false property when you start the locator.

After the node becomes a JMX Manager, all other jmx-manager-* configuration properties listed in Configuring a JMX Manager are applied.

The following is an example of starting a new locator that also starts an embedded JMX Manager (after detecting that another JMX Manager does not exist). In addition, gfsh also automatically connects you to the new JMX Manager. For example:

gfsh>start locator --name=locator1
Starting a Geode Locator in /Users/username/apache-geode/locator1...
....
Locator in /Users/username/apache-geode/locator1 on 192.0.2.0[10334] as locator1
is currently online.
Process ID: 27144
Uptime: 5 seconds
Geode Version: 1.14
Java Version: 1.8.0_121
Log File: /Users/username/apache-geode/locator1/locator1.log
JVM Arguments: -Dgemfire.enable-cluster-configuration=true 
-Dgemfire.load-cluster-configuration-from-dir=false 
-Dgemfire.launcher.registerSignalHandlers=true 
-Djava.awt.headless=true -Dsun.rmi.dgc.server.gcInterval=9223372036854775806
Class-Path: /Users/username/apache-geode/lib/geode-core-1.2.0.jar
:/Users/username/apache-geode/lib/geode-dependencies.jar

Successfully connected to: JMX Manager [host=192.0.2.0, port=1099]

Cluster configuration service is up and running.

Locators also keep track of all nodes that can become a JMX Manager.

Immediately after creating its cache, the JMX Manager node begins federating the MBeans from other members. After the JMX Manager node is ready, the JMX Manager node sends a notification to all other members informing them that it is a new JMX Manager. The other members then put complete MBean states for themselves into each of their hidden management regions.

At any point, you can determine whether a node is a JMX Manager by using the MemberMXBean isManager() method.

Using the Java API, any managed node that has been configured with jmx-manager=true can also be turned into a JMX Manager Node by invoking the ManagementService startManager() method.

Note: If you start the JMX Manager programmatically and wish to enable command processing, you must also add the absolute path of gfsh-dependencies.jar (located in the lib directory of your installation) to the CLASSPATH of your application. Do not copy this library to your CLASSPATH, because this library refers to other dependencies in lib by a relative path.

Configuring a JMX Manager

In the gemfire.properties file, you configure a JMX manager as follows.

Stopping a JMX Manager

To stop a JMX Manager using gfsh, simply shut down the locator or server hosting the JMX Manager.

For a locator:

gfsh>stop locator --dir=locator1
Stopping Locator running in /home/user/test2/locator1 on ubuntu.local[10334] as locator1...
Process ID: 2081
Log File: /home/user/test2/locator1/locator1.log
....
No longer connected to ubuntu.local[1099].

For a server:

gfsh>stop server --dir=server1
Stopping Cache Server running in /home/user/test2/server1 ubuntu.local[40404] as server1...
Process ID: 1156
Log File: /home/user/test2/server1/server1.log
....


No longer connected to ubuntu.local[1099].

Notice that gfsh has automatically disconnected you from the stopped JMX Manager.

To stop a JMX manager using the management API, use the ManagementService stopManager() method to stop a member from being a JMX Manager.

When a Manager stops, it removes all federated MBeans from other members from its Platform MBeanServer. It also emits a notification to inform other members that it is no longer considered a JMX Manager.