Horizontal Scaling

Horizontal scaling, also known as scaling out, involves adding more instances of a service to handle increased load. In Kubernetes, this is typically achieved by increasing the number of Pods running a particular application. Let's see this in practice.

Let's recreate our stateless Flask API if it's not already running:

kubectl apply -f - <
# Namespace
apiVersion: v1
kind: Namespace
metadata:
  name: stateless-flask
---
# Deployment
apiVersion: apps/v1
kind: Deployment
metadata:
  name: stateless-flask
  namespace: stateless-flask
spec:
  replicas: 1
  selector:
    matchLabels:
      app: stateless-flask
  template:
    metadata:
      labels:
        app: stateless-flask
    spec:
      containers:
      - name: stateless-flask
        image: eon01/stateless-flask:v0
        imagePullPolicy: Never
        ports:
        - containerPort: 5000
---
# ClusterIP Service
apiVersion: v1
kind: Service
metadata:
  name: stateless-flask
  namespace:

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