First of All I am somewhat lost on this myself, though was able to make a basic working sample of a php script running in a docker image on a Google Cloud Engine vm instance inside a Container Engine cluster. Where the docs states more simply
A Container Engine cluster is a group of Compute Engine instances
running Kubernetes...
So In ANSWER to the question
Please see the following GitHub repository https://github.com/CrandellWS/Kubernetes-Php-Example
There is minimal files and source. You will find the Dockerfile in the root and a single php page in the src folder.
An automated build was setup for this via docker and can be found at https://registry.hub.docker.com/u/crandellws/kubernetes-php-example/
Replicating this would be done by forking the GitHub repository and setting up your Automated Build see: http://docs.docker.com/docker-hub/builds/
Once this is done you can then pull the docker image into a Kubernetes setup and run it. Such as the following shows with the mentioned Dockerfile:
sudo docker pull crandellws/kubernetes-php-example
sudo docker run -p 80:80 -it -d --name csupport crandellws/kubernetes-php-example
https://cloud.google.com/container-engine/docs/