部署 java 应用到 k8s 集群

部署java应用到Kubernetes集群简单流程样例

1.Java程序源码

https://github.com/linuxhub/SpringBootDemo

2.Java应用镜像

打包好的镜像： https://hub.docker.com/r/linuxhub/linuxhub_www
打包步骤如下：

# 拉取代码
git clone https://github.com/linuxhub/SpringBootDemo.git
cd SpringBootDemo/
git checkout v0.1

# 编译代码
mvn clean package

# 打包镜像
docker build --rm --tag "linuxhub_www:v1.0" .

# 运行镜像
# docker run -p 8088:8088/tcp linuxhub_www:v1.0

# 上传镜像
docker tag linuxhub_www:v1.0 linuxhub/linuxhub_www:v1.0
docker push linuxhub/linuxhub_www:v1.0

3.部署 Java 应用 到 Kubernetes集群

3.1. 创建 Deployment

文件: linuxhub-web-deploy.yaml

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: linuxhub-web-deploy
spec:
  replicas: 2
  template:
    metadata:
      labels:
        app: linuxhub-web
    spec:
      containers:
      - name: linuxhub-web
        image: linuxhub/linuxhub_www:v1.0
        ports:
        - containerPort: 8088

部署 kubectl apply -f linuxhub-web-deploy.yaml

查看 Deployment 状态

# 查看 Deployment
$ kubectl get Deployment
NAME                  DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
linuxhub-web-deploy   2         2         2            2           1m
​
# 查看 pod
$ kubectl get pod -o wide 
NAME                                   READY     STATUS    RESTARTS   AGE       IP             NODE
linuxhub-web-deploy-85bcd95868-7bf7g   1/1       Running   0          4m        172.30.30.6    k8s-node-12
linuxhub-web-deploy-85bcd95868-qzx7n   1/1       Running   0          4m        172.30.34.12   k8s-node-13
​
# 查看 labels
$ kubectl get pod  --show-labels
NAME                                   READY     STATUS    RESTARTS   AGE       LABELS
linuxhub-web-deploy-85bcd95868-7bf7g   1/1       Running   0          3m        app=linuxhub-web,pod-template-hash=4167851424
linuxhub-web-deploy-85bcd95868-qzx7n   1/1       Running   0          3m        app=linuxhub-web,pod-template-hash=4167851424

3.2. 创建 service

文件: linuxhub-web-svc.yaml

apiVersion: v1
kind: Service
metadata:
  name: linuxhub-web-svc
  labels:
    app: linuxhub-web
spec:
  type: ClusterIP
  selector:
    app: linuxhub-web
  ports:
  - name: http
    port: 8088
    targetPort: 8088

部署 kubectl apply -f linuxhub-web-svc.yam

查看 service 状态

$ kubectl get service -o wide
NAME                  TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)       AGE       SELECTOR
linuxhub-web-svc      ClusterIP   10.254.198.130   <none>        8088/TCP      18s       app=linuxhub-web
​
$ kubectl describe service linuxhub-web-svc
Name:              linuxhub-web-svc
Namespace:         default
Labels:            app=linuxhub-web
Annotations:       kubectl.kubernetes.io/last-applied-configuration={"apiVersion":"v1","kind":"Service","metadata":{"annotations":{},"labels":{"app":"linuxhub-web"},"name":"linuxhub-web-svc","namespace":"default"},"spec...
Selector:          app=linuxhub-web
Type:              ClusterIP
IP:                10.254.119.59
Port:              http  8088/TCP
TargetPort:        8088/TCP
Endpoints:         172.30.30.6:8088,172.30.34.12:8088
Session Affinity:  None
Events:            <none>

3.3.创建 Ingress

文件: linuxhub-web-ingress.yaml

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: linuxhub-web-ingress
  annotations:
    kubernetes.io/ingress.class: traefik
spec:
  rules:
  - host: demo.linuxhub.cn
    http:
      paths:
      - path: /
        backend:
          serviceName: linuxhub-web-svc
          servicePort: 8088

部署 kubectl apply -f linuxhub-web-ingress.yaml

查看 ingress 状态

$ kubectl get ingress
NAME                     HOSTS                  ADDRESS   PORTS     AGE
linuxhub-web-ingress     demo.linuxhub.cn                 80        2s

4.访问

正常业务前面还需配置负载均衡与DNS解析，另外上面流程也在jenkins中配置自动构建。

配置 host

#192.168.8.12 demo.linuxhub.cn
192.168.8.13 demo.linuxhub.cn

访问URL
http://demo.linuxhub.cn/hello
http://demo.linuxhub.cn/index