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 😃

MIT License Copyright (c) 2023 Yusuf Shakeel

Donate

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