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/configmap.yaml

@@ -0,0 +1,43 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: app-config
+data:
+  MAX_REQUESTS: "10"
+
+  app.js: |
+    const http = require("http");
+
+    const MAX_REQUESTS = Number(process.env.MAX_REQUESTS || 3);
+
+    let requestCount = 0;
+
+    console.log("MAX_REQUESTS =", MAX_REQUESTS);
+
+    const server = http.createServer((req, res) => {
+      if (req.url === "/health") {
+        if (requestCount > MAX_REQUESTS) {
+          console.log('❌ O health check falhou');
+          return;
+        }
+
+        res.writeHead(200);
+        res.end(`ok`);
+        return;
+      }
+
+      requestCount++;
+      console.log("request", requestCount);
+
+      if (requestCount > MAX_REQUESTS) {
+        console.log(`🔥 App travado após ${MAX_REQUESTS} requests`);
+        return;
+      }
+
+      res.writeHead(200);
+      res.end(`Req -> ${requestCount}/${MAX_REQUESTS}`);
+    });
+
+    server.listen(3000, () => {
+      console.log("App rodando na porta 3000");
+    });

aula-03/deployment.yaml

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+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

aula-03/service.yaml

@@ -0,0 +1,12 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: node-bugado
+spec:
+  type: LoadBalancer
+  selector:
+    app: node-bugado
+  ports:
+    - port: 3000
+      targetPort: 3000
+      protocol: TCP