24 hours performance test execution stopped abruptly running in jmeter pod in AKS

Question

I am running load test of 24 hours using Jmeter in Azure Kubernetes service. I am using Throughput shaping timer in my jmx file. No listener is added as part of jmx file. My test stopped abruptly after 6 or 7 hrs.

jmeter-server.log file under Jmeter slave pod is giving warning --> WARN k.a.j.t.VariableThroughputTimer: No free threads left in worker pool.

Below is snapshot from jmeter-server.log file.

Using Jmeter version - 5.2.1 and Kubernetes version - 1.19.6

I checked, Jmeter pods for master and slaves are continously running(no restart happened) in AKS. I provided 2GB memory to Jmeter slave pod still load test is stopped abruptly. I am using log analytics workspace for logging. Checked ContainerLog table not getting error.

Snapshot of JMX file. Using following elements -> Thread Group, Throughput Controller, Http request Sampler and Throughput Shaping Timer

Please suggest for same.

Answer 1

It looks like your Schedule Feedback Function configuration is wrong in its last parameter

The warning means that the Throughput Shaping Timer attempts to increase the number of threads to reach/maintain the desired concurrency but it doesn't have enough threads in order to do this.

So either increase this Spare threads ration to be closer to 1 if you're using a float value for percentage or increment the absolute value in order to match the number of threads.

Quote from documentation:

Example function call: ${__tstFeedback(tst-name,1,100,10)} , where "tst-name" is name of Throughput Shaping Timer to integrate with, 1 and 100 are starting threads and max allowed threads, 10 is how many spare threads to keep in thread pool. If spare threads parameter is a float value <1, then it is interpreted as a ratio relative to the current estimate of threads needed. If above 1, spare threads is interpreted as an absolute count.

More information: Using JMeter’s Throughput Shaping Timer Plugin

However it doesn't explain the premature termination of the test so ensure that there are no errors in jmeter/k8s logs, one of the possible reasons is that JMeter process is being terminated by OOMKiller