My application has a load balancer which distributes payloads to two test servers. I need to test the load balancing using jmeter. Do I need to have an instance of jmeter run on all these servers to test this? How can I test this efficiently using jmeter? I also have to take out one of the test servers during load and see the response as well. Please advise how to proceed.
You should test the configuration you will be using in production, i.e. use single endpoint (which is the loadbalancer) instead of direct backend node hosts. You should not be running JMeter on any of the backend machines to avoid mutual interference. If single JMeter instance will not be enough to create the anticipated load and you will go for the distributed testing JMeter slave nodes (load generators) need to be installed outside the application under test.
Also if your Load Balancer in its turn has multiple IP addresses make sure your add DNS Cache Manager to your Test Plan to avoid IP caching on OS/JVM levels
Have a look to other questions, for example: JMeter - load balancing
And you'll certainly find some interesting tips in the
JMeter user manual
Related
I'd few ques on technical details of JMeter mostly pertaining to distributed setup vs independent JMeter engines (since JMeter controller can become a bottleneck in case of several JMeter load generators). Would be great if anybody can help with the understanding here -
How is JMeter distributed setup orchestrated by JMeter controller (i.e. called master or client)? Can we use the same logic to synchronize test among independent JMeter engines (independent mode)?
Is there a way to pool connections across vUsers?
Function of ASYNC_QUEUE in backend listener and it's expected side-effects in independent mode (mentioned above), what happens when queue is full?
Does/Is there a way for JMeter to execute javascript/act as headless browser?
How does DNS resolution happen for JMeter? Does it resolve for each vuser?
Your "question" looks like a compilation of interview questions rather than something connected with your single current concern and I don't think it's a proper place/way to ask it, I believe it should be: one post - one question.
Whatever
How is JMeter distributed setup orchestrated by JMeter controller - JMeter master sends .jmx script to slaves and collects results from them. Theoretically you can implement your own mechanism for delivering the test plan and eventual dependencies to the individual JMeter engines and running the test at the same time. Then you will need to collect the .jtl results files from the engines and combine it into a single one.
Is there a way to pool connections across vUsers? - JMeter does it internally
When the queue is full no more new sample results will be taken for processing by the backend listener so the results won't be "realtime" anymore, you will see the new results as free slots will be appearing in the queue
For JMeter per-se - no, AJAX calls can be simulated using Parallel Controller, for client-side performance testing, JavaScript execution profiling and rendering speed measurement you will need to use a read browser, no matter normal or headless, there is WebDriver Sampler plugin providing JMeter integration with Selenium
DNS resolution is dependent on underlying OS and/or JVM DNS resolution implementation, there is DNS Cache Manager which enables overriding hosts entries and using custom DNS resolver so each thread looks up the IP address on its own
I want to create a Jmeter script to test an asp.net core application. The application acts as a load balancer that distributes request to other asp.net core app running.
I want to test the efficacy of the algorithm I used, so I am looking for how to get the number of times a user or request was sent to each of the load-balanced application.
Can I use Jmeter for this? If not what test can I do? I am using Jmeter because it will load test the application.
JMeter doesn't know anything about underlying architecture of your application so it can give you only the number of the hits you made to the load balancer via Server Hits Per Second
If you need to include the number of hits to each application which is behind the load balancer you might want to use something like JMeter PerfMon Plugin which can either read the values from the file or execute an arbitrary shell command on the remote host so if you can expose the number of hits so Server Agent could consume it and plot the charts for each backend server behind the load balancer.
It also makes sense to add DNS Cache Manager to your test plan to avoid IP resolved IP addresses caching on JVM or OS level as under certain circumstances JMeter may hit only one IP address out of several
I have to perform load testing on a load balanced (clustered) system composed of three servers.
Is it a good practice to test via JMeter each server ? Or maybe it would be better testing the whole cluster calling the load balancer dedicated endpoint ?
Thanks !
Well behaved load test needs to mimic real life application usage as close as possible therefore if the load balancer acts as a single entry point to the system - JMeter needs to hit this endpoint only so the whole system will be like a "black box".
With regards to distributed systems testing best practices you can also consider the following couple of areas:
Load balancers may route requests depending on the origin so it might be a good idea to implement IP Spoofing so each JMeter virtual user could have its own source IP address.
Load Balancer endpoint host(s) may have multiple IP addresses so consider DNS Cache Manager to your Test Plan so each JMeter virtual user could resolve endpoint address on its own as due to caching of DNS calls on OS or JVM level your test can hit one node only while others will be idle.
Testing the whole system is always better. I mean you can find out problem with the load balancing management. It's always better to be in the same condition as the production environment.
After your assessment of the first test. You can regulate and find out that maybe one server is slowing down the chain with another test.
The answer is both (and you should find more cases.), You need to test your system on load as much as close to real environment to know its capabillities.
But also ,for example, when upgrading a version, sometimes only a few or even one server remain online and you need to know what load it can sustain .
I want to test a mobile application with 30k load in jmeter with cloud set-up,as i have never done such a huge v.user load in jmeter and with distributed load,please help me how to proceed with detailed step by step.
I have worked in jmter for past 5-6 months but with only one load generator machine with 200-300 V.user.
The approach is the same but with one interim step.
Configure JMeter for the maximum performance. See 9 Easy Solutions for a JMeter Load Test “Out of Memory” Failure for tuning tips.
Determine how many users you are able to simulate from a single machine (gradually increase the number of users and monitor load generator resources consumption)
Calculate how many machines you will need
Install JMeter and run jmeter-server on them. See Apache JMeter Distributed Testing Step-by-step guide for details
Run your test, analyze results, raise issues.
The JMeter documentation brilliantly captures how to run a distributed test. With that said, in a nutshell -
you would need one machine to act as a master and others as a slave
manage your data on each node (look at setting up some CI tool to help run some copy jobs before you kick off your test. This will help copy your test data accordingly)
You have 3 options:
Simple One : Use a SAAS solution that offers JMeter, there a many:
Redline13
Flood.io
Blazemeter
LoadFocus
Use this free tool that allows load testing on AWS
Use JMeter distributed testing, you can see this new tutorial from Apache JMeter
To ensure you have the most efficient test, ensure you follow best-practices.
Apache Jmeter allows us to hit the server with simultaneous connections. On, the other hand I have 4 webservers - one acting as a load balancer and other 3 acting as a application server. So, i want to load test these servers at once to check its performance. Is there a way to load test a load balancer. Any tools that will be helpful to carry out. I will edit this question further with more information. For time being could someone point out a starting point.
Ramp your normal app-test as usual (through the load balancer).
Eventually, you'll get high response times. If you see your application servers are running fine, then it's (probably*) your load balancer that's the issue. If the application servers are falling over, then you don't need to worry about the performance of your load balancer- it's not the bottleneck.
*obviously, there could be other problems, eg, simple network throughput. But you should be able to tell what's going on with some simple monitoring.
Yes you can make a load test on your load balancer Apache server.
Target your http requests to the load balancer apache server. I'm assuming the LB will distribute the load evenly through the 3 backend servers. After the test you evaluate the response times. Are they good? Great.
If they aren't good you can make a second test targeting the 3 backend servers (don't let the requests pass by the LB). If the response times are better now then you know your LB is the problem, otherwise you may need to add more backend servers or optimize your applications (i guess this is what you'll do).