I call Python script via exec blocking function inside php file which is served by Nginx. It works as expected. Python script executes Selenium using webdriver Chrome and returns xml output.
The problem is when I create more requests (2 and more) in the same time. First request is processed (nginx, php, python) and the second waits for finish of the first. They are not parallel executed.
Python script executed directly from shell can be parallel executed without problems.