An OpenShift/Kubernetes template to deploy Selenium Grid Server on OpenShift. It will start a Hub, a Chrome and a Firefox nodes and connect them to the Hub.

Table of Contents

• How to use?
  • Import the template
  • Concurrency
  • Scale-up
  • Auto-scale
  • Oops, I messed up everything!
• What is Selenium?
• Supported browsers
• Contributing
• Credits

How to use?

Build the images

Form your OpenShift console, import ./openshift/templates/build-images.yaml, and build the different images.

lternatively, you can login to OpenShift via the oc command line:

$ oc login

and import it with:

$ oc create -f openshift/build-images.yaml

Import the template

Import the template ./openshift/templates/selenium-grid.yaml in OpenShift.

Or with the command line:

$ oc login

and import it with:

$ oc create -f openshift/selenium-grid.yaml

Wait a few seconds for the three deployments to startup, and ... voilà! Your Selenium Grid server is up and running.

Note that the path /grid/console only lets you view your grid from a browser. Most webdrivers will need to be configured at the subpath /wd/hub.

From OpenShift, your grid should look like this:

And from Selenium, it should look like that:

Tasty! 🍬

Concurrency

The grid is pre-configured to register one node dedicated to Chrome tests, and one node for Firefox tests. The Chrome node can start up to 3 Chrome instances in parallel, and same for Firefox.
It means that:

• 3 users can execute tests on Chrome at the same time (same for Firefox)
• 1 user can split a long-running test over 3 Chrome instances in order to test 3 times faster (same for Firefox)
• any other combination

Scaling up

Having 3 instances is nice, but what if you need more?
You can scale-up the grid in two different ways.

Multiplying the nodes

You can add new nodes to the grid by directly scaling-up the associated OpenShift deployments, like so:

And now from Selenium, your grid should look like this:

Now you have 30 Chrome and 20 Firefox instances. Wow!

Enlarging the nodes

Alternatively, you can increase the capacity of an existing node by setting the environment variables NODE_MAX_INSTANCES and NODE_MAX_SESSION on its Deployment:

Save, wait for the re-deployment, and check your grid:

So which one should you do?
The choice is entirely up to you, depending on your needs and the resources you want to allocate. But keep in mind that you'd rather a few nodes using all their CPU and RAM than a lot of node underusing their resources.

Auto-scale

@TODO Implement auto-scaling

Oops, I messed up everything!

Don't worry, you can easily perform a full cleanup and start over again.

Just make sure you are logged in by opening a command and running:

oc login

and then run the commands available in ./openshift/clear_selenium-grid.bat.

What is Selenium?

Selenium automates browsers. That's it! What you do with that power is entirely up to you. Primarily, it is for automating web applications for testing purposes, but is certainly not limited to just that. Boring web-based administration tasks can (and should!) also be automated as well.

Selenium has the support of some of the largest browser vendors who have taken (or are taking) steps to make Selenium a native part of their browser. It is also the core technology in countless other browser automation tools, APIs and frameworks.

See the Selenium site for documentation on usage within your test code.

Contributing

Heck! Your favorite browser/version is not supported? Or want to improve the project in any other way? Your contribution is more than welcome!

Credits

Credits to the Selenium community's hard work and especially ddavidson and Jeroen Wolff from whom the Docker images and templates are adapted.