e-ian / flask-kubectl-utility

Flask and MySQL microservices deployment on Kubernetes

This repository contains code that deploys two microservices, i.e:-

1. Deploys a Flask API to add, delete and modify users in the MySQL database
2. Deploys a MySQL server on kubernetes cluster
3. Attaches a persistent volume to it, so the data remains contained if pods are restarting

Prerequisites

1. Have Docker and Kubernetes CLI (kubectl) installed together with Minikube.

Setup

1. Clone the repository
2. Configure Docker to use the Docker daemon in your kubernetes cluster via your terminal: eval $(minikube docker-env)
3. Pull the latest mysql image from Dockerhub: Docker pull mysql
4. Build a kubernetes-api image with the Dockerfile in this repo: Docker build . -t flask-api

K8 Secrets

Kubernetes Secrets can store and manage sensitive information. For this example we will define a password for the root user of the MySQL server using the Opaque secret type.

1. Encode your password in your terminal: echo -n super-secret-password | base64
2. Add the output to the flask-secrets.yml file at the db_root_password field

Deployments for the Flask and MySQL microservices

1. Add the secrets to your kubernetes cluster: kubectl apply -f flask-secrets.yml
2. Create the persistent volume and persistent volume claim for the database: kubectl apply -f mysql-pv.yml
3. Create the MySQL deployment: kubectl apply -f mysql-deployment.yml
4. Create the Flask API deployment: kubectl apply -f flaskapp-deployment.yml

Databases and Schema

1. Connect to your MySQL database by setting up a temporary pod as a mysql-client: kubectl run -it --rm --image=mysql --restart=Never mysql-client -- mysql --host mysql --password=<super-secret-password>
2. Create the database and table
   • CREATE DATABASE flaskapi;
   • USE flaskapi;
   • USE flaskapi;
   • CREATE TABLE users(user_id PRIMARY KEY AUTO_INCREMENT, user_name VARCHAR(255), user_email VARCHAR(255), user_password VARCHAR(255));

Expose the Flask API

The Flask API can be exposed and accessed by using: minikube service flask-service command. This returns a URL which you can paste in the browser and see a Welcome to my Flask Api message. You can use this service_URL to make requests to the API

Making requests

You can use the API to perform create, read, update and delete operations to your database. You can use postman or curl

1. Add a user: curl -H "Content-Type: application/json" -d '{"name": "<user_name>", "email": "<user_email>", "password": "<user_password>"}' <service_URL>/add_user
2. Get all users: curl <service_URL>/get_users
3. Get details of a specific user: curl <service_URL>/get_user/<user_id>
4. Delete a user by user_id: curl -H "Content-Type: application/json" <service_URL>/delete_user/<user_id>
5. update a user's information: curl -H "Content-Type: application/json" -d {"name": "<user_name>", "email": "<user_email>", "password": "<user_password>", "user_id": <user_id>} <service_URL>/update_user