Brooklyn JMXRMI Agent Notes

Are there any examples of using the JMX agent? There doesn't seem to be any inside the brooklyn project, so I guess the users are hidden in some AMP-specific entities? [...] I'm trying to enable JMX-based sensors for Websphere Liberty Profile

The way I usually configure entities when I want to be sure that JMX works the way I expect, I set the JMXRMI agent and ports explicitly. In a Java application class, I do it when building an EntitySpec, setting the configuration in the init() method. This is from a Cassandra cluster application I was using at Waratek:

    @Override
    public void init() {
        addChild(EntitySpec.create(CassandraDatacenter.class)
                .configure(CassandraDatacenter.CLUSTER_NAME, "Brooklyn")
                .configure(CassandraDatacenter.INITIAL_SIZE, getConfig(CASSANDRA_CLUSTER_SIZE))
                .configure(CassandraDatacenter.ENABLE_AVAILABILITY_ZONES, true)
                .configure(DynamicCluster.ZONE_PLACEMENT_STRATEGY, new WaratekNodePlacementStrategy())
                .configure(CassandraDatacenter.ENDPOINT_SNITCH_NAME, "GossipingPropertyFileSnitch")
                .configure(CassandraDatacenter.MEMBER_SPEC, EntitySpec.create(CassandraNode.class)
                        .configure(UsesJmx.USE_JMX, Boolean.TRUE)
                        .configure(UsesJmx.JMX_AGENT_MODE, JmxAgentModes.JMX_RMI_CUSTOM_AGENT)
                        .configure(UsesJmx.JMX_PORT, PortRanges.fromString("30000+"))
                        .configure(UsesJmx.RMI_REGISTRY_PORT, PortRanges.fromString("40000+"))
                        .policy(PolicySpec.create(ServiceFailureDetector.class))
                        .policy(PolicySpec.create(ServiceRestarter.class)
                                .configure(ServiceRestarter.FAILURE_SENSOR_TO_MONITOR, ServiceFailureDetector.ENTITY_FAILED)))
                .policy(PolicySpec.create(ServiceReplacer.class)
                        .configure(ServiceReplacer.FAILURE_SENSOR_TO_MONITOR, ServiceRestarter.ENTITY_RESTART_FAILED)));
    }

The important parts are the USE_JMX, JMX_AGENT_MODE, JMX_PORT and RMI_REGISTRY_PORT ConfigKey (all from the UsesJmx interface) settings. We enable JMX; set the agent mode to use the JMXRMI custom agent explicitly; and then set the PortRange for the JMX and RMI registry ports, which will be opened to allow external access. Note that if an entity uses JmxSupport#recommendJmxRmiCustomAgent() then you don't need to worry about the agent defaults.

For YAML, the following file sets up TomcatServer in a cluster, using the JMXRMI agent.

---
# Tomcat Cluster
name: "Tomcat Hello World"
location:
  jclouds:aws-ec2:eu-wast-1:
    hardwareId: m3.medium
services:
- serviceType: brooklyn.entity.webapp.ControlledDynamicWebAppCluster
  name: "Tomcat Cluster"
  brooklyn.config:
    cluster.initial.size: 1
    wars.root: https://s3-eu-west-1.amazonaws.com/cloudsoft-amp/hello-world-webapp.war
    http.port: "8080+"
    proxy.http.port: "8000+"
    memberSpec:
      $brooklyn:entitySpec:
        type: brooklyn.entity.webapp.tomcat.TomcatServer
        brooklyn.config:
          version: "7.0.53"
          jmx.enabled: true
          jmx.agent.mode: "JMX_RMI_CUSTOM_AGENT"
          jmx.direct.port: "30000+"
          rmi.registry.port: "40000+"
...

Although there's no TypeCoercions adapter registered for UsesJmx.JmxAgentModes the generic Enum<?> coercion works for this. Plus, pull request #1324 contains some updates to TypeCoercions that tries lowerCamel, lower-hyphen and UpperCamel input for all enums.

grkvlt/jmxrmi-agent-notes.md