Update Kubernetes Playground to Spring Boot 4

kubernetes/README.md

@@ -19,9 +19,11 @@ This Readme will guide you through all setup steps for the infrastructure.
 - <https://kubernetes.io/docs/reference/kubectl/cheatsheet/>
 
 ### Change Kubernetes Context
+
 ```bash
 kubectl config get-contexts
 kubectl config use-context docker-desktop
+kubectl config set-context --current --namespace=default
 ```
 
 ## Install Helm
@@ -82,3 +84,15 @@ helm upgrade --install <your-app-name> helm-charts/spring-boot-app --set name=<y
 ```bash
 helm uninstall <your-app-name>
 ```
+
+## Check Kubernetes Resources
+
+```bash
+kubectl get all -o wide
+```
+
+## Pull Traefik Image 
+
+```bash
+docker pull traefik:3
+```

kubernetes/apps/health-simulator/pom.xml

@@ -7,7 +7,7 @@
   <parent>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-parent</artifactId>
-    <version>3.5.6</version>
+    <version>4.0.0</version>
   </parent>
 
   <groupId>de.codecentric</groupId>

kubernetes/apps/health-simulator/src/main/java/de/codecentric/healthsimulator/health/HealthController.java

@@ -1,7 +1,7 @@
 package de.codecentric.healthsimulator.health;
 
 import lombok.RequiredArgsConstructor;
-import org.springframework.boot.actuate.health.Status;
+import org.springframework.boot.health.contributor.Status;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RestController;
 

kubernetes/apps/health-simulator/src/main/java/de/codecentric/healthsimulator/health/HealthIndicatorSimulation.java

@@ -2,9 +2,9 @@
 
 import lombok.Getter;
 import lombok.Setter;
-import org.springframework.boot.actuate.health.Health;
-import org.springframework.boot.actuate.health.HealthIndicator;
-import org.springframework.boot.actuate.health.Status;
+import org.springframework.boot.health.contributor.Health;
+import org.springframework.boot.health.contributor.HealthIndicator;
+import org.springframework.boot.health.contributor.Status;
 import org.springframework.stereotype.Component;
 
 @Component

kubernetes/apps/hello-world/pom.xml

@@ -7,7 +7,7 @@
   <parent>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-parent</artifactId>
-    <version>3.5.6</version>
+    <version>4.0.0</version>
   </parent>
 
   <groupId>de.codecentric</groupId>

kubernetes/apps/spring-boot-admin-discoveryclient/deployment/values.yml

@@ -1,5 +1,4 @@
 name: spring-boot-admin-discoveryclient
-namespace: default
 
 deployment:
   env:

kubernetes/apps/spring-boot-admin-discoveryclient/pom.xml

@@ -7,7 +7,7 @@
   <parent>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-parent</artifactId>
-    <version>3.5.6</version>
+    <version>4.0.0</version>
   </parent>
 
   <groupId>de.codecentric</groupId>
@@ -20,8 +20,8 @@
   <properties>
     <java.version>17</java.version>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <spring-boot-admin.version>3.5.5</spring-boot-admin.version>
-    <spring-cloud.version>2025.0.0</spring-cloud.version>
+    <spring-boot-admin.version>4.0.0-M1</spring-boot-admin.version>
+    <spring-cloud.version>2025.1.0</spring-cloud.version>
   </properties>
 
   <!-- Kubernetes Discovery -->

kubernetes/apps/spring-boot-admin-fabric8/deployment/values.yml

@@ -1,5 +1,4 @@
 name: spring-boot-admin-fabric8
-namespace: default
 
 deployment:
   env:

kubernetes/apps/spring-boot-admin-fabric8/pom.xml

@@ -7,7 +7,7 @@
   <parent>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-parent</artifactId>
-    <version>3.5.6</version>
+    <version>4.0.0</version>
   </parent>
 
   <groupId>de.codecentric</groupId>
@@ -20,8 +20,8 @@
   <properties>
     <java.version>17</java.version>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <spring-boot-admin.version>3.5.5</spring-boot-admin.version>
-    <spring-cloud.version>2025.0.0</spring-cloud.version>
+    <spring-boot-admin.version>4.0.0-M1</spring-boot-admin.version>
+    <spring-cloud.version>2025.1.0</spring-cloud.version>
   </properties>
 
   <!-- Kubernetes Discovery -->

kubernetes/apps/spring-boot-admin-kubernetes/deployment/values.yml

@@ -1,5 +1,4 @@
 name: spring-boot-admin-kubernetes
-namespace: default
 
 deployment:
   env:

kubernetes/apps/spring-boot-admin-kubernetes/pom.xml

@@ -7,7 +7,7 @@
   <parent>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-parent</artifactId>
-    <version>3.5.6</version>
+    <version>4.0.0</version>
   </parent>
 
   <groupId>de.codecentric</groupId>
@@ -20,8 +20,8 @@
   <properties>
     <java.version>17</java.version>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <spring-boot-admin.version>3.5.5</spring-boot-admin.version>
-    <spring-cloud.version>2025.0.0</spring-cloud.version>
+    <spring-boot-admin.version>4.0.0-M1</spring-boot-admin.version>
+    <spring-cloud.version>2025.1.0</spring-cloud.version>
   </properties>
 
   <!-- Kubernetes Discovery -->

kubernetes/apps/spring-boot-admin-kubernetes/src/main/resources/application.yml

@@ -7,7 +7,7 @@ spring:
   boot:
     admin:
       ui:
-        # public-url: ${SPRING_BOOT_ADMIN_UI_PUBLIC_URL:http://localhost:8080}
+        # public-url: ${SPRING_BOOT_ADMIN_UI_PUBLIC_URL:http://localhost:9090}
         title: ${SPRING_BOOT_ADMIN_UI_TITLE:Spring Boot Admin}
         brand: <img src="assets/img/icon-spring-boot-admin.svg"><span>${SPRING_BOOT_ADMIN_UI_TITLE:Spring Boot Admin}</span>
   cloud:

kubernetes/helm-charts/spring-boot-admin/values.yaml

@@ -5,8 +5,7 @@ deployment:
   env:
     SPRING_BOOT_ADMIN_UI_TITLE: Spring Boot Admin - Kubernetes
   image: spring-boot-admin
-  # do not pull image but use locally built image, not recommended for production
-  pullPolicy: Never
+  pullPolicy: Always
   updateStrategy: RollingUpdate
   maxSurge: 100%
   maxUnavailable: 0%

kubernetes/helm-charts/spring-boot-app/values.yaml

@@ -3,8 +3,7 @@ namespace: default
 
 deployment:
   image: spring-boot-app-default
-  # do not pull image but use locally built image, not recommended for production
-  pullPolicy: Never
+  pullPolicy: Always
   updateStrategy: RollingUpdate
   maxSurge: 100%
   maxUnavailable: 0%
@@ -20,4 +19,4 @@ deployment:
     port: 8080
   management:
     port: 8081
-  group: default
+  group: default

kubernetes/helm-charts/spring-cloud-kubernetes-discoveryserver/README.md

@@ -6,7 +6,7 @@ https://docs.spring.io/spring-cloud-kubernetes/reference/spring-cloud-kubernetes
 
 ## Install Spring Cloud Kubernetes Discovery Server
 ```bash
-helm upgrade --install spring-cloud-kubernetes-discoveryserver .
+helm upgrade --install spring-cloud-kubernetes-discoveryserver . -f values.yaml
 ```
 
 ### Check deployment

kubernetes/helm-charts/spring-cloud-kubernetes-discoveryserver/templates/role-binding.yaml

@@ -10,4 +10,5 @@ roleRef:
   name: namespace-reader
 subjects:
   - kind: ServiceAccount
-    name: spring-cloud-kubernetes-discoveryserver
+    name: spring-cloud-kubernetes-discoveryserver
+    namespace: {{ .Values.namespace }}

kubernetes/helm-charts/spring-cloud-kubernetes-discoveryserver/templates/role.yaml

@@ -1,7 +1,6 @@
 kind: Role
 apiVersion: rbac.authorization.k8s.io/v1
 metadata:
-  namespace: default
   name: namespace-reader
 rules:
 - apiGroups:

kubernetes/helm-charts/spring-cloud-kubernetes-discoveryserver/values.yaml

@@ -3,8 +3,8 @@ namespace: default
 
 deployment:
   # https://hub.docker.com/r/springcloud/spring-cloud-kubernetes-discoveryserver/tags
-  image: springcloud/spring-cloud-kubernetes-discoveryserver:3.3.0
-  pullPolicy: IfNotPresent
+  image: springcloud/spring-cloud-kubernetes-discoveryserver:5.0.0-M4
+  pullPolicy: Always
   updateStrategy: RollingUpdate
   maxSurge: 100%
   maxUnavailable: 0%

kubernetes/helm-charts/traefik/README.md

@@ -6,7 +6,7 @@ https://doc.traefik.io/traefik/getting-started/quick-start-with-kubernetes/
 
 ## Install Traefik
 ```bash
-helm upgrade --install traefik .
+helm upgrade --install traefik . -f values.yaml
 ```
 
 ### Check deployment

kubernetes/helm-charts/traefik/templates/deployment.yaml

@@ -2,6 +2,7 @@ kind: Deployment
 apiVersion: apps/v1
 metadata:
   name: traefik-deployment
+  namespace: {{ .Values.namespace }}
   labels:
     app: traefik
 
@@ -18,7 +19,7 @@ spec:
       serviceAccountName: traefik-account
       containers:
         - name: traefik
-          image: traefik:v2.9
+          image: {{ .Values.deployment.image }}
           args:
             - --api.insecure
             - --providers.kubernetesingress

kubernetes/helm-charts/traefik/templates/role-binding.yaml

@@ -10,4 +10,4 @@ roleRef:
 subjects:
   - kind: ServiceAccount
     name: traefik-account
-    namespace: default # Using "default" because we did not specify a namespace when creating the ClusterAccount.
+    namespace: {{ .Values.namespace }}

kubernetes/helm-charts/traefik/templates/role.yaml

@@ -4,18 +4,29 @@ metadata:
   name: traefik-role
 
 rules:
+  # Core Kubernetes Ressourcen
   - apiGroups:
       - ""
     resources:
       - services
       - endpoints
       - secrets
+      - nodes
     verbs:
       - get
       - list
       - watch
+  # EndpointSlices
+  - apiGroups:
+      - discovery.k8s.io
+    resources:
+      - endpointslices
+    verbs:
+      - list
+      - watch
+      - get
+  # Standard Kubernetes Ingress API
   - apiGroups:
-      - extensions
       - networking.k8s.io
     resources:
       - ingresses
@@ -25,7 +36,6 @@ rules:
       - list
       - watch
   - apiGroups:
-      - extensions
       - networking.k8s.io
     resources:
       - ingresses/status

kubernetes/helm-charts/traefik/templates/service.yaml

@@ -2,6 +2,7 @@ apiVersion: v1
 kind: Service
 metadata:
   name: traefik-dashboard-service
+  namespace: {{ .Values.namespace }}
 
 spec:
   type: LoadBalancer
@@ -15,6 +16,7 @@ apiVersion: v1
 kind: Service
 metadata:
   name: traefik-web-service
+  namespace: {{ .Values.namespace }}
 
 spec:
   type: LoadBalancer

kubernetes/helm-charts/traefik/values.yaml

@@ -0,0 +1,4 @@
+namespace: default
+
+deployment:
+  image: traefik:3