[Hawkular-dev] using hawkular wildfly agent as a custom java agent

Thu Mar 24 05:27:50 EDT 2016

Hi Matt,

Answers inline

2016-03-23 14:47 GMT+01:00 Matt Wringe <mwringe at redhat.com>:

> ----- Original Message -----
> > From: "John Mazzitelli" <mazz at redhat.com>
> > To: "Discussions around Hawkular development" <
> hawkular-dev at lists.jboss.org>
> > Sent: Wednesday, March 23, 2016 9:28:03 AM
> > Subject: [Hawkular-dev] using hawkular wildfly agent as a custom java
> agent
> >
> > This is for Matt, but figured post here for public consumption.
> >
> > The question was asked yesterday, "Can we use the Hawkular WildFly Agent
> to
> > monitor other things other than WildFly?"
>
> My question should have been more:
>
> "Do we have plans to have other Agents than just the WildFly one"
>

Here is the list of reporters I know we're working on:
- hawkular-agent
- vertx-hawkular-metrics
- heapster plugin
- ptrans
- all language clients (hawkular-go, hawkular-ruby, ... etc)

There is a JIRA in Metrics for a Node plugin.

>
> For me, being able to gather metrics from a WildFly server is really
> awesome, but when I am dealing with multiple systems I am going to want to
> be able to manage all those metrics in the same place.
>
> Currently its possible for a user to custom write their own component to
> interface with the Hawkular Metrics server, but in this case it seems like
> we are asking all our users to continuously write their own agents. Which
> is not very user friendly and causes a bunch of duplication of effort.
>

This is not true. Many development platforms have plugins to report data
over the Graphite text protocol. The goal of the ptrans project is to allow
reuse of existing monitoring infrastructure by forwarding data sent over
widely used monitoring network protocols to the Metrics HTTP interface.

>
> It would be awesome to be able to provide more agents that would be simple
> to setup and configure for different systems.
>

We already have a few projects (see above) but obviously there's a limit in
the number of reporters the core team can maintain. ptrans lets us benefit
from a wide ecosystem of independent metric collectors.

>
> If I am mostly running a bunch of different Java application, including
> WildFly, its going to be really tough to convince me to use Hawkular if its
> only going to monitor a subset of my systems. I would be much better off
> using Jolokia or something similar which can monitor all or most of my
> applications.
>

Correct me if I'm wrong, but Jolokia is not a collection system. It is an
HTTP adaptor around JMX. I would argue that a great majority of Java
applications either:
- collect monitoring data with home-built systems and publish to JMX
- collect monitoring data with Dropwizard Metrics

In the former case, user can combine jmxtrans(or embedded jmxtrans) with
ptrans. In the latter, Dropwizard can be configured to send data over the
Graphite protocol to ptrans.

>
> >
> > I gave one answer, but forgot there is a second alternative.
> >
> > ====
> >
> > The first answer that I gave is that you can use the Hawkular Wildfly
> Agent
> > to collect JMX data via Jolokia interface. There is an integration in the
> > agent that lets you define your resource and metric metadata and your
> > JMX/Jolokia servers. As an example, see here:
> >
> https://github.com/hawkular/hawkular-agent/blob/b52529823ca3c54d0b8b4aa560d568cd114afdec/hawkular-wildfly-agent-feature-pack/src/main/resources/subsystem-templates/hawkular-wildfly-agent.xml#L736-L817
> >
> > You define where your JMX servers are via the <remote-jmx> managed server
> > like this:
> >
> >    <remote-jmx name="Remote JMX" enabled="false"
> >    resourceTypeSets="MainJMX,MemoryPoolJMX"
> >    url="http://localhost:8080/jolokia-war"/>
> >
> > OK, that's the JMX integration. Maybe useful, maybe not. But I mention it
> > just in case.
>
> Having the agent running in an EAP instance be able to monitor other
> jolokia end points is cool. But I don't really understand why this isn't a
> more standalone java application. I would think it would be much more
> useful to be able to have a standalone java agent which could run on the
> same system which is exposing the jolokia endpoint. Say I am only running
> Tomcat servers and I don't want to run Wildfly just to be able to gather
> the metrics from Tomcat.
>
> > ====
> >
> > The second alternative I forgot to mention was the ability for any
> component
> > running in WildFly to obtain a Hawkular Agent proxy via JNDI and use that
> > proxy that store inventory and metrics into the Hawkular Server.
> >
> > There is an example WAR module in the agent git repo that demonstrates
> how to
> > obtain the proxy via JNDI and how to store inventory and metrics - see
> here:
> >
> https://github.com/hawkular/hawkular-agent/tree/master/hawkular-wildfly-agent-itest-parent/hawkular-wildfly-agent-example-jndi
> >
> > This is just a simple WAR with a servlet. But it shows how a component
> can
> > get the agent proxy via JNDI here:
> >
> >
> https://github.com/hawkular/hawkular-agent/blob/master/hawkular-wildfly-agent-itest-parent/hawkular-wildfly-agent-example-jndi/src/main/java/org/hawkular/agent/example/HawkularWildFlyAgentProvider.java#L32-L35
> >
> > Here's code that shows the servlet doing things like sending metrics,
> avail,
> > and creating resources:
> >
> >
> https://github.com/hawkular/hawkular-agent/blob/master/hawkular-wildfly-agent-itest-parent/hawkular-wildfly-agent-example-jndi/src/main/java/org/hawkular/agent/example/MyAppServlet.java
> >
> > No one is using this yet. So there may be issues I am not aware of, but
> we
> > have integration tests that show this working.
> >
> > This was put together with the anticipation of someone asking for this
> > capability - that is, "can the agent be used to collect metrics for other
> > things other than WildFly". Essentially, this just gives you a skeleton
> Java
> > agent that you can extend to collect your own metrics and inventory. So
> you
> > can write a WAR or EAR, deploy it in any WildFly that has an agent
> > subsystem, and your EAR/WAR can be used as an "agent" for your custom
> stuff.
> >
> > Again, maybe useful, maybe not. But I mention it just in case.
>
> Being able to expose custom metrics is extremely important. Awesome that
> we have the ability to do that with the agent currently :)
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-- 
Thomas Segismont
JBoss ON Engineering Team
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