Glowroot – Java Application Performance Management (APM)

This blog will cover

• What is APM
• Glowroot – Overview
• Configuration – Embedded Collector
• Persistence Option with Docker – Central Collector

What is APM?

• In a production environment, it’s important to keep an eye on resource consumption.
• This is where various monitoring tools come in.
• When it comes to Java there are various open-source monitoring tools.
• One of which is Glowroot.
• I personally like Glowroot because of its simplicity and ease to configure.

Glowroot

• Glowroot is open-source Java APM.
• Read more detail here
• Live Demo to see how it works and decide if it useful for your Application.

Download src

Configuration – Embedded Collector

• Download Glowroot src from the above link and extract.
• Folder with name glowroot will contains all dependencies to configure and run.
• In your application, you need to add the following lines -javaagent:path/to/glowroot.jar in JVM args.
• If you are using Apache Tomcat in Eclipse keep ongoing.
• Don’t worry if you are using other servers just refer this link

Apache Tomcat in Eclipse

• Open Servers Tab
• Double click on Tomcat Server or you can right-click the server and select Open
• Apache configuration will show up.
• Click on Open Launch Congratulation under General Information. a window will pop up.
• In that go to Arguments and add lines at last in VM argument
• like this -javaagent:/home/username/Documents/glowroot/glowroot.jar
• Refer below image

Note: This Embedded Collector’s data will not be persisted. So if Application stops, all data is lost.

Persistence Option with Docker – Central Collector

• If you want data to be persisted.
• You can go to Central Collector. I recently tried out this in docker and its just 2 commands to setup Collector.

docker run --name mycassandra -d cassandra

docker run --name myglowroot \
--link mycassandra:cassandra \
--publish 0.0.0.0:4000:4000 \
--publish 0.0.0.0:8181:8181 \
glowroot/glowroot-central:0.10.12

• Once done. Your collector is ready to work at dockerip:8181
• Now we need to to send data to this collector.
• Steps are the same as described in Embedded Collector.
• Except for 1 additional step.
• We will have to add glowroot.properties file in glowroot folder(where your glowroot jar is) with this data

agent.id=Docker
collector.address=http://localhost:8181

• Now you will have all your data persisted in Cassandra DB.

Note: By adding glowroot.properties you are telling to run central Collector instead of Embedded. So to run Embedded yo just need to delete this property file.

Useful link for other options