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

If you are running Firefox on a system with no display, make sure you use headless mode.

from selenium import webdriver
from selenium.webdriver.firefox.options import Options

options = Options()
options.headless = True
driver = webdriver.Firefox(options=options)

Also, make sure you have compatible versions of Firefox, Selenium, and Geckodriver: https://firefox-source-docs.mozilla.org/testing/geckodriver/Support.html

Thumb rule

A common cause for Browsers to crash during startup is running WebDriver initiated Browsers as root user (administrator) on Linux. While it is possible to work around this issue by passing --no-sandbox flag when creating your WebDriver session, such a configuration is unsupported and highly discouraged. You need to configure your environment to run Browser as a regular user instead.

This error message...

selenium.common.exceptions.WebDriverException: Message: invalid argument: can't kill an exited process

...implies that the GeckoDriver was unable to initiate/spawn a new WebBrowsing Session i.e. Firefox Browser session.

Your main issue is the incompatibility between the version of the binaries you are using as follows:

• Your GeckoDriver version is 0.22.0.

• Release Notes of GeckoDriver v0.21.0 (2018-06-15) clearly mentions the following:

• Firefox 57 (and greater)

• Selenium 3.11 (and greater)

• Your Firefox version is 52.9.0.

So there is a clear mismatch between GeckoDriver v0.22.0 and the Firefox Browser v57

Solution

• Upgrade GeckoDriver to GeckoDriver v0.22.0 level.
• GeckoDriver is present in the specified location.
• GeckoDriver is having executable permission for non-root users.
• Upgrade Firefox version to Firefox v62.0.2 levels.
• Clean your Project Workspace through your IDE and Rebuild your project with required dependencies only.
• If your base Web Client version is too old, then uninstall it through Revo Uninstaller and install a recent GA and released version of Web Client.
• Execute your Selenium Test as a non-root user.

GeckoDriver, Selenium and Firefox Browser compatibility chart

I was on headless mode, using correct versions of everything, and the only way to get out of this error message was not to execute the selenium test as root

Yes checked Start Xvfb before the build can fix the problem, but if you have a job like a pipeline or multibranch pipeline this option is not visible. In the node of your Selenium grid that you go to execute the test you need:

1- Install Xvfb: apt install xvfb

2- Execute Xvfb: /usr/bin/Xvfb :99 -ac -screen 0 1024x768x8 & export DISPLAY=":99"

3- Rerun your node, for example: java -jar selenium.jar -role node -hub http://#.#.#.#:4444/grid/register -capabilities browserName=firefox,plataform=linux -host #.#.#.# -port 1991

This solution worked for me

from selenium import webdriver
from selenium.webdriver.firefox.options import Options

options = Options()
options.headless = True
driver = webdriver.Firefox(options=options)