Kubernetes Microservice Flask Application

Introduction

In this blog post, we will learn how to deploy a microservices project on Kubernetes using Minikube. Minikube is a tool that allows you to run a single-node Kubernetes cluster on your local machine.

Prerequisites

• ➡️Basic Understanding of Minikube: This tutorial assumes you have a fundamental understanding of Minikube concepts such as starting and managing a local Kubernetes cluster.

• ➡️Minikube Installed and Running: To actively engage in this practical exercise, you need to have Minikube installed and a functional local Kubernetes cluster set up.

• https://devxblog.hashnode.dev/minikube-easy-local-kubernetes-setup-and-first-pod

Let's Start

Step 1: Cloning the Source Code of the Project

git clone https://github.com/Simbaa815/microservices-k8s.git

This step involves cloning the repository where your project's source code is stored.

Step 2: Build the Dockerfile

Create a Dockerfile in the root directory of your project with the following content:

FROM python:alpine3.7
COPY . /app
WORKDIR /app
RUN pip install -r requirements.txt
ENV PORT 5000
EXPOSE 5000
ENTRYPOINT [ "python" ]

Now we will build a Docker Image from this Dockerfile.

docker build . -t your_username/microservicespythonapp:latest

Step 3: Push the Docker Image to Docker Hub

docker login
docker push your_username/microservicespythonapp:latest

This step involves building the Docker image and pushing it to your Docker Hub repository. Replace your_username, with your docker hub username.

Step 4: Creating a Persistent Volume Manifest for K8s

Create a file named mongo-pv.yml with the following content:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: mongo-pv
  namespace: microservices-k8s
spec:
  capacity:
    storage: 256Mi
  volumeMode: Filesystem
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: /home/nid/mongo-dv

This defines a PersistentVolume named mongo-pv with a capacity of 256Mi and uses the host path /home/nid/mongo-dv for storage.

Step 5: Creating a Persistent Volume Claim (PVC) Manifest in K8s

Create a file named mongo-pvc.yml with the following content:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mongo-pvc
  namespace: microservices-k8s
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 256Mi

This creates a PersistentVolumeClaim named mongo-pvc requesting 256Mi of storage with ReadWriteOnce access mode.

Step 6: Create a Deployment Manifest File of MongoDB

Create a file named mongo-deployment.yml with the following content:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: mongo-deployment
  namespace: microservices-k8s
spec:
  replicas: 1
  selector:
    matchLabels:
      app: mongo
  template:
    metadata:
      labels:
        app: mongo
    spec:
      containers:
        - name: mongo
          image: mongo:latest
          ports:
            - containerPort: 27017
          volumeMounts:
            - name: mongo-storage
              mountPath: /data/db
      volumes:
        - name: mongo-storage
          persistentVolumeClaim:
            claimName: mongo-pvc

This deploys a single MongoDB container with the necessary configurations, including a PersistentVolumeClaim named mongo-pvc.

Step 6: Create a Service Manifest File of MongoDB

Create a file named mongo-svc.yml with the following content:

apiVersion: v1
kind: Service
metadata:
  name: mongo-service
spec:
  selector:
    app: mongo
  ports:
    - protocol: TCP
      port: 27017
      targetPort: 27017
  selector: mongo

This creates a NodePort service named mongo-svc for the MongoDB deployment.

Step 7: Create the Deployment Manifest File of the Flask App

Create a file named taskmaster.yml with the following content:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: taskmaster
  namespace: microservices-k8s
  labels:
    app: taskmaster
spec:
  replicas: 1
  selector:
    matchLabels:
      app: taskmaster
  template:
    metadata:
      name: taskmaster
      namespace: microservices-k8s
      labels:
        app: taskmaster
    spec:
      containers:
        - name: taskmaster
          image: simbaa815/microservicespythonapp:latest
          ports:
            - containerPort: 5000
          imagePullPolicy: Always

Step 8: Create the Service Manifest File of the Flask App

Create a file named flask-app-svc.yml with the following content:

apiVersion: v1
kind: Service
metadata:
  name: taskmaster-svc
  namespace: microservices-k8s
spec:
  selector:
    app: taskmaster
  ports:
    - protocol: TCP
      port: 80
      targetPort: 5000
      nodePort: 30007
  type: NodePort

This creates a NodePort service named taskmaster-service.yml for the Flask app deployment.

Step 9: Test the Application

Once you have applied all the manifests, use kubectl to monitor the status of your resources:

kubectl get pods
kubectl get deployments
kubectl get services

Make sure everything is running as expected.

In Minikube: How to verify this

kubectl port-forward pod/<pod_name> <local_port>:<target_port> -n <namespace>

Simply past to the IP in the web-browser that is shown in the first line

For further clarification and insights, please visit this

Congratulations on completing the deployment of your Microservices Project! 🚀🎉

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