Jmeter Distributed (Remote) Testing: Master Slave Configuration-Chapter 10

What is Distributed Testing?

Distributed Testing is a kind of testing which use multiple systems to perform Stress Testing. Distributed testing is applied for testing websites and server applications when they are working with multiple clients simultaneously.

Distributes testing uses client-server model as the figure below:

• Master: the system running JMeter GUI, control each slave.
• Slave: the system running JMeter-server, receive a command from the master and send a request to a server under test.
• Target: the web server under test, get a request from slaves.

Remote Test Example

Precondition:

• The firewalls on the systems are turned off. In some cases, the firewall may still be blocking the traffic. You should disable the Window firewall or Linux firewall.
• All the machines should be on the same subnet. If machines are not on the same subnet, maybe they will not recognize each other in the network.
• Use the same version of JMeter to avoid unanticipated errors/issues.

Here is the roadmap for this testing:

Step 1) System configuration

Setup slave systems, go to jmeter/bin directory and execute file "jmeter-server.bat".

Assume that a slave machine has IP address: 192.168.0.10. On windows, you should see a window appear like the following figure:

On the master systems, go to /bin directory and edit file jmeter.properites, add IP slave machine as below

Step 2) Run the test

At this point, you are ready to start load testing. On the master machine, run JMeter GUI and open the test plan.

Click Run on the menu bar; select Remote start -> select the IP address of slave machine

Step 3) Troubleshooting

If you are unable to run test form the above machine and see below error, simply ask an owner of a slave machine to run the JMeter-server.bat File.

Disable Firewall on both master and slave machines to fix this error.

Limitation:

There are some basic limitations for distributed testing. Here's list of the known items:

• Server and all clients must be on the same subnet.
• Distributed testing required target server to have the large processing power. The target Server could be easily overloaded in case it gets too many requests by distributed JMeter tests.
• A single JMeter can only handle a limited number of threads (100- 300 threads).
• The distributed JMeter tests are complex, difficult for a beginner to build.

HTTP Proxy Server in JMeter: Record Example Script-chapter 11

Record Testing help tester to record & run their activity against test target. It is a type of automated testing but for multiple users. This tutorial guides you how to use Proxy Server to record your test.

The Proxy Server allows JMeter to watch and record user activity while they are browsing web application with a normal browser.

In this tutorial, you will learn

• Step 1) Setting HTTP Proxy server
• Step 2) Record your activity
• Step 3) Run your Test Plan
• Step 4) Save your test result

Here is the roadmap of this practical example

Step 1) Setting the HTTP Proxy server

This is a Step-by-step guide to setup proxy

1. Start JMeter
2. Select Test Plan on the tree
3. Add Thread Group
   Right click on the Test Plan and add a new thread group: Add => Threads (Users) =>Thread Group

4. Add HTTP Request
   Select the Thread Group; right click Add => Config Element => HTTP Request Defaults

In new HTTP Request Defaults element: In Server name or IP, enter "google.com". You should keep the others fields blank

5. Add Recording Controller
   Right click on the "Thread Group" and add a recording controller: Add => Logic Controller =>
   Recording Controller

6. Add Proxy Server to WorkBench
   Right click on the Workbench and add the http proxy: Add => Non-Test Elements => HTTP Proxy Server  
   
7. Set Target Controller where your recorded scripts will be added

8. Start Proxy Server
   Return to HTTP Proxy Server, and click the Start button at the bottom. Now your JMeter proxy server start
     
9. Start your Browser  choose Tool => Option => Advanced => Network => Setting => Enter HTTP proxy as figure below
    
   

Step 2) Record your activity

1. Now Launch http://www.google.com in your web browser (JMeter still open)
2. Do activities search the keyword "apache".
3. Back to JMeter, in HTTP Proxy Server, click Stop when finished
    
   
   
4. After finishing recording, you will see JMeter automatically created a new HTTP request as the figure below
   
   JMeter has already recorded a user request to the Home Page of Google website. Http://www.google.com/
   The other HTTP requests display in above figure, you should remove them. Because sometime JMeter also records some advertising links while you are searching keyword on Google. We should ignore them in our Test Plan
5. Click File => Save your Test Plan as
   
6. A Dialog box display => enter a name of your test plan at File Name field => Click Save
   Now your Test Plan is saved under name RecordingTestPlan.jmx

Step 3) Run your Test Plan

1. Select Thread Group => Add => Listener=> Summary Report

2. The Summary Report will show some basic statics
   
3. Select Thread Group, enter information as the figure below

4. Before you start the test, select "Summary Report". When you ready to run a test, select Run => Start (Ctrl+R). JMeter will playback your activity in 100 times
   As the test runs, the statistics will change until the test is done.
   

Step 4) Save your test result

1. Click Save Table Data to save test result to file

2. Enter the name of the test result and click Save. Test Result in JMeter is saved in *.csv format as default

What is JMeter? Why it is used?-Chapter 1

The Apache JMeterTM is pure Java open sourcesoftware, which was first developed by Stefano Mazzocchi of the Apache Software Foundation, designed to load test functional behavior and measure performance.

 You can use JMeter to analyze and measure the performance of web application or a variety of services.

Performance Testing means testing a web application against heavy load, multiple and concurrent user traffic. 

JMeter originally is used for testing Web Application or FTP application. Nowadays, it is used for a functional test, database server test etc.

Why JMeter?

Have you ever tested a web server to know how efficiently it works? How many concurrent users can a web server handle?

Let say that one day, your boss asks you to do performance testing of www.google.com for 100 users. What would you do?

It's not feasible to arrange 100 people with PC and internet access simultaneously accessing google.com Think of the infrastructure requirement when you test for 10000 users (a small number for a site like google). Hence you need a software tool like JMeter that will simulate real-user behaviors and performance/load test your site.

JMeter Advantages

JMeter advantages are described as figure below

• Open source license: JMeter is totally free,  allows developer use the source code for the development
• Friendly GUI: JMeter is extremely easy to use and doesn't take time to get familiar with it
• Platform independent: JMeter is 100% pure Java desktop application. So it can run on multiple platforms
• Full multithreading framework. JMeter allows concurrent and simultaneous sampling of different functions by a separate thread group
• Visualize Test Result: Test result can be displayed in a different format such as chart, table, tree and log file
• Easy installation: You just copy and run the *.bat file to run JMeter. No installation needed.
• Highly Extensible: You can write your own tests. JMeter also supports visualization plugins allow you to extend your testing
• Multiple testing strategy: JMeter supports many testing strategies such as Load Testing, Distributed Testing, and Functional Testing.
• Simulation: JMeter can simulate multiple users with concurrent threads, create a heavy load against web application under test
• Support multi-protocol: JMeter does not only support web application testing but also evaluate database server performance. All basic protocols such as HTTP, JDBC, LDAP, SOAP, JMS, and FTP are supported by JMeter
• Record & Playback - Record the user activity on the browser and simulate them in a web application using JMeter
• Script Test: Jmeter can be integrated with Bean Shell & Selenium for automated testing.

How does JMeter work?

The basic workflow of JMeter as shown in the figures below

JMeter simulates a group of users sending requests to a target server, and return statistics information of target server through graphical diagrams

The completed workflow of JMeter as shown in the figure below

Jmeter Version History

Version	Description
1	first official release
2.13	Java 6+
3	Java 7+
3.1	Java 7+
3.2	Java 8+
3.3	Java 8
4	Java 8 / 9

How to Use JMeter for Performance & Load Testing-Chapter 5

Performance Testing is crucial to determine that the web application under test will satisfy high load requirements. It can be used to analyze overall server performance under heavy load.

Apache JMeter testing tool offers following benefit in Performance Testing

• JMeter can be used to test the performance of both static resources such as JavaScript and HTML, as well as dynamic resources, such as JSP, Servlets, and AJAX.
• JMeter can discover maximum number of concurrent users that your website can handle
• JMeter provides a variety of graphical analyses of performance reports.

JMeter Performance Testing includes:

• Load Testing: Modeling the expected usage by simulating multiple user access the Web services concurrently.
• Stress Testing: Every web server has a maximum load capacity. When the load goes beyond the limit, the web server starts responding slowly and produce errors. The purpose of the Stress Testing is to find the maximum load the web server can handle.

The figure below shows how JMeter load Testing simulates the heavy load:

Create a Performance Test Plan in JMeter

In this tutorial, we are doing a performance analysis of Google.com for 1000 users

Before testing the performance of target web application, we should determine-

• Normal Load: Average number of users visit your website
• Heavy Load: The maximum number of users visit your website
• What is your target in this test?

Here is the roadmap of this practical example

Step 1) Add Thread Group

1. Start JMeter
2. Select Test Plan on the tree
3. Add Thread Group

Right click on the "Test Plan" and add a new thread group: Add -> Threads (Users) -> Thread Group

In the Thread Group control panel, enter Thread Properties as follows:

• Number of Threads: 100 (Number of users connects to the target website: 100)
• Loop Count: 10 (Number of time to execute testing)
• Ramp-Up Period: 100

The Thread Count and The Loop Counts are different.

Ramp-Up Period tells JMeter how long to delay before starting the next user. For example, if we have 100 users and a 100-second Ramp-Up period, then the delay between starting users would be 1 second (100 seconds /100 users)

Step 2) Adding JMeter elements

Now we determine what JMeter elements in this test. The elements are

• HTTP request Default

This element can be added by right-clicking on the Thread Group and selecting: Add -> Config Element -> HTTP Request Defaults.

In the HTTP Request Defaults control panel, enter the Website name under test (http://www.google.com)

• HTTP Request

Right-click on Thread Group and select: Add -> Sampler -> HTTP Request.

In HTTP Request Control Panel, the Path field indicates which URL request you want to send to Google server.

For example, if you enter "calendar" in Path field. JMeter will create the URL request http://www.google.com/calendar  to Google server

If you keep the Path field blank  JMeter will create the URL request http://www.google.com to Google server.

In this test, you keep the Path field blank to make JMeter create the URL request http://www.google.com to Google server.

Step 3) Adding Graph result

JMeter can show the test result in Graph format.

Right click Test Plan, Add -> Listener -> Graph Results

Step 4) Run Test and get the test result

Press the Run button (Ctrl + R) on the Toolbar to start the software testing process. You will see the test result display on Graph in the real time.

The picture below presents a graph of a test plan, where we simulated 100 users who accessed on website www.google.com.

At the bottom of the picture, there are the following statistics, represented in colors:

• Black: The total number of current samples sent.
• Blue: The current average of all samples sent.
• Red: The current standard deviation.
• Green: Throughput rate that represents the number of requests per minute the server handled

Let analyze the performance of Google server in below figure.

To analyze the performance of the web server under test, you should focus on 2 parameters

• Throughput
• Deviation

The Throughput is the most important parameter. It represents the ability of the server to handle a heavy load.  The higher the Throughput is, the better is the server performance.

In this test, the throughput of Google server is 1,491.193/minute. It means Google server can handle 1,491.193 requests per minute. This value is quite high so we can conclude that Google server has good performance

The deviation is shown in red - it indicates the deviation from the average. The smaller the better.

Let compare the performance of Google server to other web servers. This is the performance test result of website http://www.yahoo.com/ (You can choose other websites)

The throughput of a website under test http://www.yahoo.com is 867.326/minutes. It means this server handle 867.326 requests per minute, lower than Google.

The deviation is 2689, much higher than Google (577). So we can determine the performance of this website is less than a Google server.

NOTE: The above values depend on several factors like current server load at Google, your internet speed, your CPU power etc. Hence, it's very unlikely that you will get the same results as above.