A containerised stateful application for use in the Kubernetes for Cloud Foundry course.
It has been pushed to Dockerhub and can be pulled at engineerbetter/stateful-app.
When deployed without a Redis, the stateful-app utilises Sinatra's sessions, storing information in the app's memory.
When deployed to a Kubernetes Cluster where a Redis instance can be detected, the application, upon starting, will use the Redis to store state.
How does this work you ask? When and service is deployed to a Kubernetes cluster, a series of environment variables are set to enable service discovery. The stateful-app uses one of these (REDIS_MASTER_SERVICE_HOST) to determine whether to use a deployed Redis.
$ git clone [email protected]:EngineerBetter/stateful-k8s-app.git
$ rackupVisit the application at localhost:9292
$ git clone [email protected]:EngineerBetter/stateful-k8s-app.git
$ docker build -t engineerbetter/stateful-app .
# Get the image of the recently built image
$ docker images
# Run the image and expose it on port 9292
$ docker run -p 9292:9292 <IMAGE ID>Visit the app at 0.0.0.0:9292