<p>I use distributed jmeter for load tests in Kubernetes. To maximize the number of concurrent threads I use several Jmeter server instances.</p>
<p>My test plan has 2000 users, so I have 10000 concurrent users with 5 Jmeter servers. Each user send 1 request per second to Kafka. This runs without any problems.</p>
<p>But if I increase the number of server instances up to 10, Jmeter gets a lot of errors when sending requests and is not able to send the required rate of requests per second.</p>
<p>Is there a way to use more than 5 server instances in Jmeter (my cluster has 24vCPUs and 192gb ram)?</p>

bennex
<p>Theoretical maximum value of slaves is very high, you can have as many as <a href="https://en.wikipedia.org/wiki/2,147,483,647" rel="nofollow noreferrer">2 147 483 647</a> slaves which is a little bit more than 5.</p>
<p>So my expectation is that the problem is somewhere else, i.e. there is a <a href="http://kafka.apache.org/090/documentation.html" rel="nofollow noreferrer">maximum number of connections per IP</a> defined or the broker is running out of resources</p>
<p>We cannot give meaningful advices unless we have more details, in the meantime you can check:</p>
<ul>
<li><a href="https://jmeter.apache.org/usermanual/get-started.html#logging" rel="nofollow noreferrer">jmeter.log files</a> for master and slaves</li>
<li><a href="https://www.blazemeter.com/blog/how-to-save-response-data-in-jmeter" rel="nofollow noreferrer">response data</a></li>
<li>kafka logs</li>
<li>resource consumption on kafka broker(s) side, it can be done using i.e. <a href="https://jmeter-plugins.org/wiki/PerfMon/" rel="nofollow noreferrer">JMeter PerfMon Plugin</a></li>
</ul>
