Spring boot发布到k8s并加载Configmap配置文件,实现配置热更新

在项目开发中, 大都会为不同的运行环境编写不同的配置文件, 比如生产环境使用application-prod.yml, 开发环境使用application-dev.yml.

在spring boot 应用部署到k8s之前, 配置文件的挂载一般都会在打jar包时包含在内, 或者把配置文件的内容保存在nacos之类的中间件中在启动应用时读取配置.

在应用k8s之后,  配置文件可以在通过ConfigMap资源剥离出来单独部署,  本次记录spring boot框架的java应用结合k8s的ConfigMap的实现外部配置文件挂载及配置热更新的一次实践。

一、配置自动更新，需要引入 kubernetes-config、健康检测依赖

1、项目依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.7.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo-v6</artifactId>
    <version>0.0.1</version>
    <name>demo-v6</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-kubernetes-config</artifactId>
            <version>1.1.8.RELEASE</version>
        </dependency>
        <!-- 用于健康监测自动刷新 -->
<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-actuator-autoconfigure</artifactId>
        </dependency>
    </dependencies>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Hoxton.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

2、使用到配置项的代码

@RefreshScope
@RestController
public class HelloController {
 
    @Value("${name:null}")
    private String name;
 
    @Value("${age:0}")
    private int age;
 
    @GetMapping("/hello")
    public Object hello () {
        return name + ": " + age;
    }
}

3、Dockerfile

FROM openjdk:8-jdk-alpine
RUN mkdir -p /app/
COPY ./demo-v6-0.0.1.jar /app/
RUN touch /app/demo-v6-0.0.1.jar
RUN ln -sf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime

4、添加账号角色绑定demo-account.yaml

apiVersion: v1
kind: ServiceAccount
metadata:
  name: config-reader
  namespace: demo
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: pod-reader
  namespace: demo
rules:
- apiGroups:
  - ""
  resources:
  - endpoints
  - pods
  - configmaps
  verbs:
  - list
  - get
  - watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: pod-reader
  namespace: demo
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: pod-reader
subjects:
- kind: ServiceAccount
  name: config-reader
  namespace: demo

5、configmap

apiVersion: v1
kind: ConfigMap
metadata:
  name: demo-configmap
  namespace: demo
  labels:
    spring.cloud.kubernetes.config: "true"
data:
  application.yml: |-
    server:
      port: 8989
    
    spring:
      application:
        name: demo-configmap
    
      cloud:
        kubernetes:
          config:
            sources:
            - name: demo-configmap
              namespace: demo
          reload:
            #自动更新配置的开关设置为打开
            enabled: true
            monitoring-config-maps: true
            monitoring-secrets: true
            mode: polling
            strategy: refresh
    
    management:
      endpoints:
        web:
          exposure:
            include: refresh,health
      endpoint:
        restart:
          enabled: true
        health:
          enabled: true
        info:
          enabled: true
    
    age: 18
    name: Tom

6、后端yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: demo
  namespace: demo
  labels:
    app: demo
spec:
  replicas: 1
  selector:
    matchLabels:
      app: demo
  template:
    metadata:
      labels:
        app: demo
    spec:
      serviceAccountName: config-reader
      imagePullSecrets:
      - name: harbor-secret
      containers:
      - name: demo
        image: 192.168.1.6:8037/demo:0.0.1
        imagePullPolicy: Always
        command: ["java", "-jar", "/app/demo-v6-0.0.1.jar"]
        args: ["--spring.config.location=/app/config/application.yml", "--spring.profiles.active=dev"]
        ports:
        - containerPort: 8001
        volumeMounts:
        - name: host-time
          mountPath: /etc/localtime
        - name: demo-config
          mountPath: /app/config
      volumes:
      - name: host-time
        hostPath:
          path: /etc/localtime
      - name: demo-config
        configMap:
          name: demo-configmap
---
apiVersion: v1
kind: Service
metadata:
  name: demo
  namespace: demo
  labels:
    app: demo
spec:
  type: ClusterIP
  ports:
  - port: 8001
   targetPort: 8001
  selector:
    app: demo

效果：

configmap修改前：

 configmap修改后：

 二、手动触发滚动更新，无须引入任何依赖

1、configmap

apiVersion: v1
kind: ConfigMap
metadata:
  name: demo-configmap
  namespace: demo
  labels:
    spring.cloud.kubernetes.config: "true"
data:
  application.yml: |-
    server:
      port: 8989 
    spring:
      application:
        name: demo-configmap    
    age: 18
    name: Tom

 2、后端yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: demo
  namespace: demo
  labels:
    app: demo
spec:
  replicas: 1
  selector:
    matchLabels:
      app: demo
  template:
    metadata:
      labels:
        app: demo
    spec:
      imagePullSecrets:
      - name: harbor-secret
      containers:
      - name: demo
        image: 192.168.1.6:8037/demo:0.0.1
        imagePullPolicy: Always
        command: ["java", "-jar", "/app/demo-v6-0.0.1.jar"]
        args: ["--spring.config.location=/app/config/application.yml", "--spring.profiles.active=dev"]
        ports:
        - containerPort: 8001
        volumeMounts:
        - name: host-time
          mountPath: /etc/localtime
        - name: demo-config
          mountPath: /app/config
      volumes:
      - name: host-time
        hostPath:
          path: /etc/localtime
      - name: demo-config
        configMap:
          name: demo-configmap
---
apiVersion: v1
kind: Service
metadata:
  name: demo
  namespace: demo
  labels:
    app: demo
spec:
  type: ClusterIP
  ports:
  - port: 8001
   targetPort: 8001
  selector:
    app: demo

3、利用patch更新annotation的值，来触发pod滚动更新

kubectl patch deployment -n demo --patch '{"spec": {"template": {"metadata": {"annotations": {"version/config": "20220614" }}}}}'

三、Secret保存账号密码信息

思路：jasypt加密 -> ENC(加密后的字符串) -> base64编码 -> Secret

1、jasypt加密

2、base64编码

 

 3、secret

 4、后端引用yaml

 5、修改configmap值后，发现程序中的值不会自动更新，采用手动方式触发刷新

curl ‘ip:port/actuator/refresh’