dee-me-tree-or-love / kubernetes-sandbox

Different educational projects with K8S 🪄

Kubernetes Sandbox

Simple system to experiment with Kubernetes, Skaffold and friends

Components

Lotr-Quotes

Is a simple Node.js Express service giving a random quote out of 50 "Lord Of The Rings" quotes.
Runs on port 8080.

route	purpose
GET: /quote	returns JSON: {quote, author}
GET: /ready	returns JSON: {ready} to indicate if ready to serve

Python-Starter

Is a simple Python Flask service checking if the other service is ready (and pretends to be starting it).
Runs on port 5000.

route	purpose
GET: /	returns TEXT: <whether ready or not message>

Message-Writer

Is a simple Python Flask service that publishes the received messages to the rabbitmq service.

route	purpose
POST: /publish	for JSON input: '{"<your subject>": "<your message>"}' publishes the content to the queue of topic <your subject>

Food-Message-Worker

A listening process that waits for the incoming messages from the rabbitmq queue with food topic.
Is not a service, but a running pod. Replicated to 5 (maybe different number) instances.

Food-Job-Worker

Is a Job container performing some action on the supplied food job.
Expects the job suppied as an environment variable MY_JOB_ITEM.

env_key	value	operation
MY_JOB_ITEM	string: <any string value>	simply reverses the supplied item and writes the result to the console.

Infrastructure

Skaffold

Disclaimer: use Skaffold v0.23.0 while sync issues are not solved.

The definition for the Skaffold project is described in skaffold.yaml.
It uses the file-sync option to update container code without rebuilding.
Important to notice, that for the sync option the mapping should correspond to the WORKDIR of the associated DockerFile

# in skaffold.yaml
...
build:
  artifacts:
  - image: gcr.io/k8s-skaffold/lotr-quotes
    context: ./lotr-quotes/
    sync:
      '**/*.js': /usr/src/app
...

# ~~

# in ./lotr-quotes/Dockerfile
...
WORKDIR /usr/src/app
...

Rabbitmq

The deployment of a rabbitmq service is described in ./insfrastructure/rabbitmq/k8s/deployment.yaml.