UPDATE As mentioned in the comments, this is a bad idea. If you are considering Load Testing with Selenium Grid, reconsider your purpose and verify whether Selenium Grid really is the only option you have.
For a free solution:
Selenium provides an easily scalable testing framework called Selenium Grid. You can use this in conjunction with TestNG to create a scalable load-testing framework.
From the link:
scale by distributing tests on several machines ( parallel execution )
manage multiple environments from a central point, making it easy to run the tests against a vast combination of browsers / OS.
minimize the maintenance time for the grid by allowing you to implement custom hooks to leverage virtual infrastructure for instance.
I have leveraged Selenium Grid to load-test our web-app with about a dozen concurrent browser sessions (so far). I used several references to achieve this:
- http://testng.org/doc/documentation-main.html#parallel-tests
- http://blog.wedoqa.com/2013/07/how-to-run-parallel-tests-with-selenium-webdriver-and-testng-2/
- http://www.mkyong.com/unittest/testng-selenium-load-testing-example/
