henrynyarko/wordsmith

Sample project with Docker containers running under Kubernetes

Wordsmith App

Wordsmith is the demo project originally shown at DockerCon EU 2017 and 2018.

The demo app runs across three containers:

• api - a Java REST API which serves words read from the database
• web - a Go web application that calls the API and builds words into sentences
• db - a Postgres database that stores words

Architecture

Build and run in Docker Compose

The only requirement to build and run the app from source is Docker. Clone this repo and use Docker Compose to build all the images. You can use the new V2 Compose with docker compose or the classic docker-compose CLI:

docker compose up --build

Or you can pull pre-built images from Docker Hub using docker compose pull.

Deploy using Kubernetes manifests

You can deploy the same app to Kubernetes using the Kustomize configuration. It will define all of the necessary Deployment and Service objects and a ConfigMap to provide the database schema.

Apply the manifest using kubectl while at the root of the project:

kubectl apply -k .

Once the pods are running, browse to http://localhost:8080 and you will see the site.

Docker Desktop includes Kubernetes and the kubectl command line, so you can work directly with the cluster. Check the services are up, and you should see output like this:

kubectl get svc
NAME         TYPE           CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE
db           ClusterIP      None             <none>        55555/TCP        2m
kubernetes   ClusterIP      10.96.0.1        <none>        443/TCP          38d
web          LoadBalancer   10.107.215.211   <pending>     8080:30220/TCP   2m
words        ClusterIP      None             <none>        55555/TCP        2m

Check the pods are running and you should see one pod each for the database and web components and five pods for the words API:

kubectl get pods
NAME                   READY     STATUS    RESTARTS   AGE
db-8678676c79-h2d99    1/1       Running   0          1m
web-5d6bfbbd8b-6zbl8   1/1       Running   0          1m
api-858f6678-6c8kk     1/1       Running   0          1m
api-858f6678-7bqbv     1/1       Running   0          1m
api-858f6678-fjdws     1/1       Running   0          1m
api-858f6678-rrr8c     1/1       Running   0          1m
api-858f6678-x9zqh     1/1       Running   0          1m