learn-k8s

This project is about learning Kubernetes.

Table of Content

Prerequisite
Getting started
Postman Collection
Localhost server
API endpoints
Docker Image
Docker Container in localhost
Tests
Kubernetes files

Prerequisite

This project depends on the following.

NodeJS (v14 or higher)
Docker (Optional. Needed only if you want to create docker image and run the project in a container.)

Getting started

This is a NodeJS project. To get started, first install all the packages by running the following command in the terminal.

npm i

Postman Collection

Check the docs folder.

Localhost server

To start the localhost server.

npm run start

API endpoints

Check out the docs folder. It has the Postman collection.

Home

curl --location 'http://0.0.0.0:3000'

Response:
Status: 200 Content-Type: application/json
Body:
{
    "data": {
        "message": "Hello, World!",
        "hostname": "Yusufs-MBP-2"
    }
}

Liveness

Use this for livenessProbe in Kubernetes.

When the app is live.

curl --location 'http://0.0.0.0:3000/liveness'

Response: 
Status: 200 Content-Type: application/json
Body:
{
    "data": {
        "message": "I am live!"
    }
}

When the app is not live.

curl --location 'http://0.0.0.0:3000/liveness'

Response:
Status: 500 Content-Type: application/json
Body:
{
    "data": {
        "message": "I am not live!"
    }
}

Liveness: make unhealthy

This API will make the app liveness unhealthy. Pass the TTL in seconds.

Request:
{
  "data": {
    "ttl": 100
  }
}

Default ttl: 60 seconds.

curl --location --request PUT 'http://0.0.0.0:3000/liveness/make/unhealthy' \
--header 'Content-Type: application/json' \
--data '{"data":{"ttl": 10}}'

Response:
Status: 200 Content-Type: application/json
Body:
{
    "data": {
        "message": "I am unhealthy!"
    }
}

Readiness

Use this for readinessProbe in Kubernetes.

When the app is ready.

curl --location 'http://0.0.0.0:3000/readiness'

Response:
Status: 200 Content-Type: application/json
Body:
{
    "data": {
        "message": "I am ready!"
    }
}

When the app is not ready.

curl --location 'http://0.0.0.0:3000/readiness'

Response:
Status: 500 Content-Type: application/json
Body:
{
    "data": {
        "message": "I am not ready!"
    }
}

Readiness: make unhealthy

This API will make the app readiness unhealthy. Pass the TTL in seconds.

Request:
{
  "data": {
    "ttl": 100
  }
}

Default ttl: 60 seconds.

curl --location --request PUT 'http://0.0.0.0:3000/readiness/make/unhealthy' \
--header 'Content-Type: application/json' \
--data '{"data":{"ttl": 10}}'

Response:
Status: 200 Content-Type: application/json
Body:
{
    "data": {
        "message": "I am unhealthy!"
    }
}

Version

curl --location 'http://0.0.0.0:3000/version'

Response:
Status: 200 Content-Type: application/json
Body:
{
    "data": {
        "version": "0.1.0"
    }
}

To change the version set the environment variable APPLICATION_VERSION=semver.

Example: APPLICATION_VERSION=1.0.0

Metadata

curl --location 'http://0.0.0.0:3000/metadata'

Response:
Status: 200 Content-Type: application/json
Body:
{
    "data": {
        "os": "darwin",
        "hostname": "Yusufs-MacBook-Pro-2.local",
        "uptime": {
            "unit": "sec",
            "quantity": "891910"
        },
        "memory": {
            "unit": "bytes",
            "quantity": "17179869184"
        },
        "cpus": [
            {
                "model": "Apple M1 Pro",
                "speed": 24,
                "times": {
                    "user": 99240520,
                    "nice": 0,
                    "sys": 57942390,
                    "idle": 219834960,
                    "irq": 0
                }
            }
        ]
    }
}

Die

This will kill the server, and it will not work anymore.

curl --location --request POST 'http://0.0.0.0:3000/die'

Response:
Status: 200 Content-Type: application/json
Body:
{
    "data": {
        "message": "Goodbye..."
    }
}

Metrics

curl --location 'http://0.0.0.0:3000/metrics'

Response:
Status: 200 Content-Type: text/plain
Body:
# HELP process_cpu_user_seconds_total Total user CPU time spent in seconds.
# TYPE process_cpu_user_seconds_total counter
process_cpu_user_seconds_total 0.22259

more line follows...

Tests

To run the test suite.

npm run test

Docker Image

DockerHub link of this project yusufshakeel/learn-k8s

To pull the image on your localhost.

docker pull yusufshakeel/learn-k8s

Docker Container in localhost

To run the docker container in localhost.

docker run -d -p 3000:3000 yusufshakeel/learn-k8s

This will start the server on port 3000.

Kubernetes files

Check the k8s folder for Kubernetes files.

License

It's free 😃

Donate

Feeling generous 😃 Donate via PayPal