Performance Engineering – JVM – Performance Monitoring (Open Source Tools)

• JVM – Performance Monitoring

• Set up a application in your local machine/environment, for us to monitor it using tools
  • Download and Extract Apache Tomcat (a java based application server)
  • Setup Java, JRE, Path and Tomcat environment variables
  • Start Tomcat by navigating to Tomcat /bin and run startup.bat
  • Ensure Tomcat server is started successfully by accessing it via http://localhost:8080

• • {tomcat-directory}/conf tomcat-users.xml file configuration

• • Login to the application by clicking Manager App button, by giving tomcat and tomcat as the user credentials, which we already configured @ /conf

• • Navigate to WAR file to deploy section and browse the .war file and click deploy

• • Once the deployment is successful, the application will be listed here

 

• • Launch the application by clicking on /jpetstore URI, ensure the application is running as below

• • Login to the application using the credentials – username (j2ee) and password(j2ee)

• • Lets understand on the two applications those comes bundled with JDK to monitor the application’s metrics (which internally uses JVM)
  • Java Visual VM (jvisualvm)
  • JConsole

• JVisual VM

  • Navigate to JDK/bin and open jvisualvm to view that the JPetStore application is already being listed to be monitored, as the application utilizes the backend java runtime(JVM)

• Analyze the behavior of Heap, GC, CPU, Memory metrics via Monitor tab
• We can perform the below kinds of analysis using the Java VisualVM
  • Heap Analysis
  • Thread Analysis
  • Garbage Collection Analysis
• Access your already listed application (Tomcat being the one referred to here), Navigate to Monitor tab

• Make sure the CPU Utilization never crosses 80%, as well the Garbage Collection activity

• Discuss with DEV and Product teams to understand the results by comparing the already discussed SLA’s, and take necessary steps to resolve these issues
• Perform GC
  • Click the Perform GC button for manually performing the Garbage Collection(here on referenced as GC)
    • While you manually induce the GC, is there any impact in CPU Usage, GC Activity and Memory Usage, is the intention of performing manual GC by clicking Perform GC button
      • BTW, What is GC? – The activity of clearing the un-referenced objects in memory
• Heap Dump
• • It’s a process of taking the memory snapshot while issue, to analyze the reason of the issue

• • Capture multiple heap dump and analyze and come to an understanding and do the RCA of the issue
• Analyze the behavior of Threads via Threads tab
• We can validate various Thread status like – Running, Sleeping, Waiting, Parked, Monitored Threads

• Analyze the behavior of currently running application’s CPU and Memory data using Sampler and Profiler tabs
  • Sampler and Profiler
    • Observe the CPU metrics of the backend application’s API(methods)

• • • Observe the Memory metrics of the backend application’s API(methods)

• • • Also, Leverage the benefits of analyzing the garbage collection metrics with available plugin that comes bundled with Java VisualVM – Visual GC

• • • Once the plugin gets installed, you can monitor the GC metrics produced by Visual GC by clicking on the application name

• JConsole

  • Select the process that I want to attach/enable JConsole to monitor

• • The below were the various metrics associated with the Tomcat process that we attached above

 

• • Both JVisualVM and JConsole were intended to monitor JVM, but an added advantage of JConsole is that it’s metrics were analyzed and fetched for a desired time range as below

• • Memory metrics can be analyzed as below

• • Any Spikes, Exponential Increase in the graph, Memory related errors like OutOfMemory error will be a red flag for you while measuring the performance metrics
  • Observe and Analyze the Thread related metrics and issues under the Threads tab

• • How to take the heap dump?

• • • Navigate to MBeans tab, expand com.sun.management\Operations\dumpHeap, and browse a new file {someFileName.hprof }, and the heap dump gets created

 

-By  Saravanan & Sai Krishna