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");
+    });