isabella232 / kdemo

A Simple webapp written in Go for Kubernetes demos

Simple Go Webapp for Kubernetes Demos

This is a very simple webapp written in Go, used for Kubernetes demos. It serves a simple HTML page at the root path: /, showing the value of the HOSTNAME environment variable inside a colored bar.

The /grid path can generate a grid of iframes displaying the main page. The number of columns and rows in the grid is determined by the cols and rows query parameters respectively.

For example, to generate a 3x3 grid just use the following path: http://<hostname>:<port>/grid?cols=3&rows=3

Building the Go Executable

On a POSIX-like environment you can simply run the build.sh script. It runs the go build command with the correct configuration to generate a statically-linked, Linux ELF executable, in the current directory, simply called main. Or you can run it directly like this:

CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o main .

Please note that this is not intended to be installed in your local $GOPATH. Instead, it is used as the basis for building a Docker image as explained below.

Creating a Docker Image

After building the Linux executable just run:

docker build -t <your_image_tag> .

To upload the new image to a public Docker Registry such as hub.docker.com push the image like this:

docker push <your_image_tag>

Creating the Kubernetes Objects

Once your Docker image has been published you can use the sample descriptor files in the kubernetes folder to create the relevant objects in a Kubernetes cluster. TO USE YOUR OWN IMAGE MAKE SURE YOU REPLACE THE image FIELD IN THE kdemo-dep.yaml FILE WITH THE TAG YOU USED ABOVE.

kubectl create -f kubernetes/kdemo-dep.yaml
kubectl create -f kubernetes/kdemo-svc.yaml

This will create a Deployment and related Service using a NodePort. Find the dynamically allocated Node port (with something like kubectl describe svc/kdemo-svc) to access the Service from outside the cluster. If you have an Ingress Controller configured in your cluster, you may find the kdemo-ing.yaml file useful in creating an Ingress for this Deployment.

Who do I talk to?

Isaac "Ike" Arias