WebDriverException: Message: invalid argument: can't kill an exited process with GeckoDriver, Selenium and Python on RaspberryPi3

Question

Server: Raspberry Pi 3
OS: Dietpi - version 159
Geckodriver version: 0.22 for arm
Firefox version: 52.9.0
Python version: 3.5
Selenium version: 3.14.1 <

Answer 1

As there can be many different underlying causes for this error it is best to find the root cause setting selenium to use debug level logging. In my case, for Ruby with capybara I needed to set: Selenium::WebDriver.logger.level = :debug. And voilà, running the same spec I could see in the logs that a dependency was missing, in my case:

libdbus-glib-1.so.2: cannot open shared object file: No such file or directory
Couldn't load XPCOM.

After installing it all worked fine.