spring-cloud-kubernetes-example

The Examples for Spring-Cloud-Kubernetes in https://github.com/seongpyoHong/spring-cloud-kubernetes.

Index

1. kubernetes-hello-world-example

Spring Cloud Kubernetes를 통해 스프링 부트 어플리케이션을 쿠버네티스 위에 배포하고, DiscoveryClient를 통해 쿠버네티스에 등록된 서비스를 조회

Result

> curl <External-Ip>:<NodePort>
Hello World!

> curl <External-Ip>:<NodePort>/services
Avaliable list of services

2. kubernetes-circuitbreaker-ribbon-example

• Netflix Ribbon을 통해 Client-Side Loadbalancing 제공
• Netfilx Hystrix를 통해 Circuit Breaker Pattern 제공

Execution

• Build docker image & Push to GCR

./gradlew jib

• Create k8s resources

kubectl apply -f resources/

result

• Pods

NAME                              READY   STATUS    RESTARTS   AGE
greeting-service-78b54b56-9495b   1/1     Running   0          6m25s
name-service-1-6f84bbd478-6v69z   1/1     Running   0          3m54s
name-service-1-6f84bbd478-wdzz9   1/1     Running   0          20m
name-service-2-df9b9bf59-wkvvw    1/1     Running   0          20m

• Get list of service

❯ curl http://34.64.104.57:30411/services
    [greeting-service, kubernetes, name-service-1, name-service-2]

• Verify loadbalance by calling name-service-1 (replicas=2)

❯ curl http://<External-Ip>:<NodePort>/greeting1
    Hello from name-service-1-6f84bbd478-6v69z! 
❯ curl http://<External-Ip>:<NodePort>/greeting1
    Hello from name-service-1-6f84bbd478-wdzz9!

• Call name-service-2 (replicas=1)

❯ curl http://<External-Ip>:<NodePort>/greeting2
    Hello from name-service-2-df9b9bf59-wkvvw!

• Test Circuit Breaker by calling name-service-2(replicas=0)
  • Timeout : 1000 ms

❯ kubectl scale --replicas=0 deployment name-service-2
    deployment.extensions/name-service-2 scaled

❯ curl http://<External-Ip>:<NodePort>/greeting2
    Hello from fallback!

3. kubernetes-reload-example

• ConfigMap / Secret 변경에 따른 auto-reload 제공

Execution

• Build docker image & Push to GCR

./gradlew jib

• Create k8s resources

kubectl apply -f resources/

• Change ConfigMap

kubectl apply -f src/configMap.yml

Result

Before Changing the ConfigMap

• ConfigMap

    apiVersion: v1
    kind: ConfigMap
    metadata:
      name: reload-example
    data:
      application.properties: |-
        bean.message=Hello World!
        another.property=value
  

• Output

    2020-03-11 13:51:21.844  INFO 1 --- [main] c.s.e.KubernetesReloadExampleApplication : Started KubernetesReloadExampleApplication in 8.698 seconds (JVM running for 9.357)
    The first message is: Hello World!
    The other message is: Dummy Message
  

After Changing the ConfigMap

• ConfigMap

    apiVersion: v1
    kind: ConfigMap
    metadata:
      name: reload-example
    data:
      application.properties: |-
        bean.message=Changed Version!
        another.property=value
  

• Output

    2020-03-11 13:55:52.554  INFO 1 --- [scheduling-1] o.s.boot.SpringApplication               : Started application in 0.436 seconds (JVM running for 280.067)
    The first message is: Changed Version!
    The other message is: Dummy Message
  

4. kubernetes-leader-election-example

Not yet stater

5. kubernetes-zipkin-example

Not yet stater