Installation

Some common installation issues

psutil/_psutil_common.c:9:10: fatal error: Python.h: No such file or directory

https://stackoverflow.com/questions/63440765/locust-installation-error-using-pip3-error-command-errored-out-with-exit-statu

ERROR: Failed building wheel for xxx

While Locust itself is a pure Python package, it has some dependencies (e.g. gevent and geventhttpclient) that are compiled from C code. Pretty much all common platforms have binary packages on PyPi, but sometimes there is a new release that doesnt, or you are running on some exotic platform. You have two options:

• Use pip install --prefer-binary locust to select a pre-compiled version of packages even if there is a more recent version available as source.
• Fix the build (google the error message, ensure you have the appropriate build tools installed etc)

Windows

https://stackoverflow.com/questions/61592069/locust-is-not-installing-on-my-windows-10-for-load-testing

Installation works, but the locust command is not found

When running pip, did you get a warning saying The script locust is installed in '...' which is not on PATH? Add that directory to your PATH environment variable.

Increasing Maximum Number of Open Files Limit

Every User/HTTP connection from Locust opens a new file (technically a file descriptor). Many operating systems by default set a low limit for the maximum number of files that can be open at the same time.

Locust will try to adjust this automatically for you, but in a lot of cases your operating system will not allow it (in which case you will get a warning in the log). Instead you will have to do it manually. How to do this depends on your operating system, but you might find some useful information here: https://www.tecmint.com/increase-set-open-file-limits-in-linux/ and practical examples https://www.ibm.com/support/knowledgecenter/SS8NLW_11.0.2/com.ibm.discovery.es.in.doc/iiysiulimits.html