11:08 a.m.
Right now, the Hawkular WildFly Agent runs as a WildFly subsystem extension - which means
it must run in EAP.
To avoid this requirement, I refactored the agent code [1] so it can be run using a
standard VM javaagent (using the VM argument -javaagent).
This means the agent need not run as a subsystem extension, in fact, it can run in any VM
(non-EAP/WildFly based). Just pass in the -javaagent command line argument to your VM and
you got an agent. You have a Karaf container in a JVM exposing metrics via JMX? You can
use this. You got a vert.x server in a JVM exposing metrics via JMX? You can use this.
This new agent's config file is a single YAML file that mimics virtually the same
settings as you see today in the agent's <subsystem> XML in standalone.xml.
Like the EAP-based agent, this new agent can still:
* collect DMR metrics and inventory from any EAP 6.4, EAP 7.x, or WildFly 10+ servers -
local or remote.
* collect JMX metrics and inventory from any remote Jolokia endpoint or local JMX
MBeanServer
* receive websocket messages from a Hawkular Server (if running in full Hawkular mode)
* run in metrics-only mode where it only stores data to Hawkular-Metrics and does not
connect via websocket to the server nor stores inventory to H-Inventory
* Talk to the Hawkular Server and remote DMR/JMX endpoints via SSL/https using defined
security-realms/keystores
Unlike the EAP-based agent, this new agent:
* does NOT have a CLI (jboss-cli.sh is the EAP-based agent's CLI)
* does NOT have a built-in configuration persistent mechanicm (EAP-based agents can
persist their config changes to standalone.xml when those changes are made via the WildFly
management interface - because the javaagent is completely independent, it has nothing
like this for its YAML config).
* does NOT integrate with the lifecycle of any EAP/WildFly running in the same VM (in
other words, if you ask to "reload" the EAP server, the javaagent knows nothing
about that and won't also itself reload. Remember, this javaagent is now completely
independent of any co-located EAP/WildFly server).
In addition, if your JVM is installed in OpenShift, you can get the nice option of putting
the javaagent's YAML config in a config map and mount it so your javaagent can access
it. This means you can edit your javaagent YAML directly in the OpenShift UI :)
I still need to see how well this supports the disabling/enabling of metrics on the fly
from the websocket commands (e.g. I will need to add the ability to change the YAML config
to persist the settings, that is not done yet - the EAP-based agent got this support for
free - its config changes go into standalone.xml).
Other than persisting changes to the YAML file, I believe this javaagent will work
essentially the same as the current agent (indeed, the core agent engine is identical -
its the same code). Just have to make sure the websocket commands can work considering
there is a YAML config backing the settings and not standalone.xml.
I need people's feedback on this. Thoughts? If you want to try it, you can build it
from my PR right now using the README [2] and the instructions [3].
--John Mazz
[1] https://github.com/hawkular/hawkular-agent/pull/302
[2]
https://github.com/jmazzitelli/hawkular-agent/blob/refactor-core/hawkular...
[3] Instructions to build using the PR and test it by collecting EAP metrics:
1) Build it:
$ git clone git@github.com:hawkular/hawkular-agent.git
$ cd hawkular-agent
$ git checkout -b jmazzitelli-refactor-core master
$ git pull https://github.com/jmazzitelli/hawkular-agent.git refactor-core
$ mvn clean install
2) Install it - assuming you have a base EAP 6.4 or 7.x or WildFly 10+ installed at
<eap.dir>
2a) Change this line in <eap.dir>/bin/standalone.conf:
JBOSS_MODULES_SYSTEM_PKGS="org.jboss.byteman"
to this:
JBOSS_MODULES_SYSTEM_PKGS="org.jboss.byteman,org.jboss.logmanager"
2b) Inside that same <eap.dir>/bin/standalone.conf you add this line in the
appropriate place (you know where, just under where it sets JAVA_OPTS):
JAVA_OPTS="$JAVA_OPTS -Djava.util.logging.manager=org.jboss.logmanager.LogManager
-javaagent:$JBOSS_HOME/bin/hawkular-javaagent-*.jar=config=$JBOSS_HOME/standalone/configuration/real-config*.yaml,delay=10"
2c) Copy the binary/config files you built to that EAP / WildFly install:
cp
hawkular-agent/hawkular-javaagent/target/hawkular-javaagent-*-jar-with-dependencies.jar
<eap.dir>/bin
if EAP 7.x/WildFly 10+:
cp hawkular-agent/hawkular-javaagent/src/test/resources/real-config.yaml
<eap.dir>/standalone/configuration
if EAP 6.4:
cp hawkular-agent/hawkular-javaagent/src/test/resources/real-config-eap6.yaml
<eap.dir>/standalone/configuration