Lab done

java-k8s-lab/Dockerfile

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+# --------- Build Stage ---------
+FROM openjdk:11 as build
+WORKDIR /app
+
+# Copy the Java source file into the container
+COPY HelloController.java .
+
+# Compile the Java source file
+RUN javac HelloController.java
+
+# Package all compiled classes into an executable jar
+RUN jar cfe app.jar HelloController *.class
+
+# --------- Run Stage ---------
+FROM openjdk:11-jre
+WORKDIR /app
+
+# Copy the executable jar from the build stage
+COPY --from=build /app/app.jar .
+
+# Expose the port on which the app listens
+EXPOSE 8080
+
+# Run the jar file
+ENTRYPOINT ["java", "-jar", "app.jar"]

java-k8s-lab/HelloController.java

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+import com.sun.net.httpserver.HttpServer;
+import com.sun.net.httpserver.HttpHandler;
+import com.sun.net.httpserver.HttpExchange;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.net.InetSocketAddress;
+
+public class HelloController {
+    public static void main(String[] args) throws IOException {
+        HttpServer server = HttpServer.create(new InetSocketAddress(8080), 0);
+        server.createContext("/", new MyHandler());
+        server.setExecutor(null);
+        server.start();
+        System.out.println("Server started on port 8080...");
+    }
+
+    static class MyHandler implements HttpHandler {
+        @Override
+        public void handle(HttpExchange t) throws IOException {
+            String response = "Hello, Kubernetes!";
+            t.sendResponseHeaders(200, response.length());
+            try (OutputStream os = t.getResponseBody()) {
+                os.write(response.getBytes());
+            }
+        }
+    }
+}

java-k8s-lab/\

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+:a# Please edit the object below. Lines beginning with a '#' will be ignored,
+# and an empty file will abort the edit. If an error occurs while saving this file will be
+# reopened with the relevant failures.
+#
+apiVersion: v1
+kind: Service
+metadata:
+  annotations:
+    kubectl.kubernetes.io/last-applied-configuration: |
+      {"apiVersion":"v1","kind":"Service","metadata":{"annotations":{},"name":"java-app-service","namespace":"default"},"spec":{"ports":[{"nodePort":30080,"port":80,"protocol":"TCP","targetPort":8080}],"selector":{"app":"java-app"},"type":"NodePort"}}
+  creationTimestamp: "2025-10-30T15:44:34Z"
+  name: java-app-service
+  namespace: default
+  resourceVersion: "29843"
+  uid: 88426e7d-7dc0-4403-98c9-ea4f622e4800
+spec:
+  clusterIP: 10.98.17.126
+  clusterIPs:
+  - 10.98.17.126
+  externalTrafficPolicy: Cluster
+  internalTrafficPolicy: Cluster
+  ipFamilies:
+  - IPv4
+  ipFamilyPolicy: SingleStack
+  ports:
+  - nodePort: 30080
+    port: 80
+    protocol: TCP
+    targetPort: 8080
+  selector:
+    app: java-app-probes
+  sessionAffinity: None
+  type: NodePort
+status:
+  loadBalancer: {}

java-k8s-lab/deployment-with-probes.yaml

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+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: java-app-with-probes
+spec:
+  replicas: 3
+  selector:
+    matchLabels:
+      app: java-app-probes
+  template:
+    metadata:
+      labels:
+        app: java-app-probes
+    spec:
+      containers:
+      - name: java-app-container
+        image: gfiamon/my-java-app:1.0   # ← Use your actual username
+        ports:
+        - containerPort: 8080
+        livenessProbe:
+          httpGet:
+            path: /
+            port: 8080
+          initialDelaySeconds: 15   # Wait 15s after container starts
+          periodSeconds: 10         # Check every 10 seconds
+          timeoutSeconds: 5         # Wait max 5s for response
+          failureThreshold: 3       # 3 failures = unhealthy
+        readinessProbe:
+          httpGet:
+            path: /
+            port: 8080
+          initialDelaySeconds: 5
+          periodSeconds: 5

java-k8s-lab/deployment.yaml

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+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: java-app-deployment
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: java-app
+  template:
+    metadata:
+      labels:
+        app: java-app
+    spec:
+      containers:
+      - name: java-app-container
+        image: gfiamon/my-java-app:1.0   # ← Replace with your username
+        ports:
+        - containerPort: 8080

java-k8s-lab/service-probes.yaml

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+apiVersion: v1
+kind: Service
+metadata:
+  name: java-app-service-probes
+spec:
+  type: NodePort
+  selector:
+    app: java-app-probes    # Matches our probe deployment
+  ports:
+    - protocol: TCP
+      port: 80
+      targetPort: 8080
+      nodePort: 30081       # Different port to avoid conflict

java-k8s-lab/service.yaml

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+apiVersion: v1
+kind: Service
+metadata:
+  name: java-app-service
+spec:
+  type: NodePort          # Makes it accessible from outside
+  selector:
+    app: java-app         # Finds pods with this label
+  ports:
+    - protocol: TCP
+      port: 80            # Service port (internal)
+      targetPort: 8080    # Pod port (where your Java app runs)
+      nodePort: 30080     # External port (for your browser)