Deployment YAML

A Deployment's spec has three important parts: replicas, the selector determining which pods belong to it, and the template, the mould for new pods. The labels in the template must match the selector:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web
  template:
    metadata:
      labels:
        app: web
    spec:
      containers:
        - name: nginx
          image: nginx:1.27
          ports:
            - containerPort: 80

In production, resources are written for each container. requests are the guaranteed amount the scheduler reserves; limits are the ceiling that can't be exceeded (a container exceeding its memory limit is OOMKilled):

          resources:
            requests:
              cpu: 100m
              memory: 128Mi
            limits:
              cpu: 500m
              memory: 256Mi

100m = 0.1 CPU core; Mi = mebibytes.