aula-03: Alta disponibilidade com replicas e readiness probe

Múltiplas réplicas com readiness probe para remover pods
não-saudáveis do Service enquanto liveness probe os reinicia.

aula-03/deployment.yaml

@@ -0,0 +1,47 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: node-bugado
+spec:
+  replicas: 5  # Alta disponibilidade: enquanto um reinicia, outros atendem
+  selector:
+    matchLabels:
+      app: node-bugado
+  template:
+    metadata:
+      labels:
+        app: node-bugado
+    spec:
+      terminationGracePeriodSeconds: 5
+      containers:
+        - name: app
+          image: node:24-alpine
+          command: ["node", "/app/app.js"]
+          env:
+            - name: MAX_REQUESTS
+              valueFrom:
+                configMapKeyRef:
+                  name: app-config
+                  key: MAX_REQUESTS
+          ports:
+            - containerPort: 3000
+          readinessProbe:
+            httpGet:
+              path: /health
+              port: 3000
+            periodSeconds: 1       # Verifica a cada 1 segundo
+            failureThreshold: 1    # 1 falha = remove do Service
+          livenessProbe:
+            httpGet:
+              path: /health
+              port: 3000
+            initialDelaySeconds: 2 # Espera para começar a testar
+            periodSeconds: 1       # A cada 1 seg faz o teste novamente
+            failureThreshold: 2    # 2 falhas = reinicia o container
+          volumeMounts:
+            - name: app-volume
+              mountPath: /app
+      volumes:
+        - name: app-volume
+          configMap:
+            name: app-config