多節點高可用Eureka叢集配置與部署
阿新 • • 發佈：2018-11-04
前言
上一節講的是動態擴容Eureka服務，說實話，一般情況這種操作並不多，一般多用在，由於大量服務節點部署後給Eureka造成壓力突然積增，而解決的辦法。這節講的是一次啟動或部署，直接就是叢集多節點的，多用於服務節點相對穩定的場景。還有筆者這裡有實際部署和應用的經驗分享給大家，就是，我目前25個服務都註冊在一個單節點Eureka上了（無論生產還是測試環境下），測試周期接近一年，我發現Eureka可靠性和可用性還是很高的，沒有出現一次註冊中心掛了的情況。還有，我一下內容沒有花裡胡哨的套話和流程圖，想必大家最想解決的就是如何快速的解決自己的問題，所以以下基本都是貼出的程式碼，關鍵地方我會文字說明。程式碼還是基於《重新定義》的思想。
正文
首先還是建立一個父module，pom配置如下：
<groupId>cn.springcloud.book</groupId> <artifactId>ch3-2</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>pom</packaging> <name>ch3-2</name> <description>ch3-2</description> <modules> <module>ch3-2-zuul-gateway</module> <module>ch3-2-eureka-server</module> <module>ch3-2-eureka-client</module> </modules> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.0.3.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> <spring-cloud.version>Finchley.RELEASE</spring-cloud.version> </properties> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>${spring-cloud.version}</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies>
然後建立EurekaServer服務，分別貼出pom檔案和啟動類
<groupId>cn.springcloud.book</groupId> <artifactId>ch3-2-eureka-server</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>ch3-2-eureka-server</name> <description>ch3-2-eureka-server</description> <parent> <groupId>cn.springcloud.book</groupId> <artifactId>ch3-2</artifactId> <version>0.0.1-SNAPSHOT</version> <relativePath>../pom.xml</relativePath> <!-- lookup parent from repository --> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build>
@SpringBootApplication
@EnableEurekaServer
public class Ch322EurekaServerApplication {
public static void main(String[] args) {
SpringApplication.run(Ch322EurekaServerApplication.class, args);
}
}然後下面的內容是多節點配置的重要部分了
我會從上到下依次貼出這個目錄的程式碼
eureka:
server:
use-read-only-response-cache: false
response-cache-auto-expiration-in-seconds: 10
management:
endpoints:
web:
exposure:
include: '*'
server:
port: 8761
spring:
application:
name: eureka-server
eureka:
instance:
hostname: localhost
preferIpAddress: true
metadataMap.zone: zone1
client:
register-with-eureka: true
fetch-registry: true
region: region-east
service-url:
zone1: http://localhost:8761/eureka/,http://localhost:8762/eureka/
zone2: http://localhost:8763/eureka/,http://localhost:8764/eureka/
availability-zones:
region-east: zone1,zone2
server:
waitTimeInMsWhenSyncEmpty: 0
enableSelfPreservation: falseserver:
port: 8762
spring:
application:
name: eureka-server
eureka:
instance:
hostname: localhost
preferIpAddress: true
metadataMap.zone: zone1
client:
register-with-eureka: true
fetch-registry: true
region: region-east
service-url:
zone1: http://localhost:8761/eureka/,http://localhost:8762/eureka/
zone2: http://localhost:8763/eureka/,http://localhost:8764/eureka/
availability-zones:
region-east: zone1,zone2
server:
waitTimeInMsWhenSyncEmpty: 0
enableSelfPreservation: falseserver:
port: 8763
spring:
application:
name: eureka-server
eureka:
instance:
hostname: localhost
preferIpAddress: true
metadataMap.zone: zone2
client:
register-with-eureka: true
fetch-registry: true
region: region-east
service-url:
zone1: http://localhost:8761/eureka/,http://localhost:8762/eureka/
zone2: http://localhost:8763/eureka/,http://localhost:8764/eureka/
availability-zones:
region-east: zone1,zone2
server:
waitTimeInMsWhenSyncEmpty: 0
enableSelfPreservation: false
server:
port: 8764
spring:
application:
name: eureka-server
eureka:
instance:
hostname: localhost
preferIpAddress: true
metadataMap.zone: zone2
client:
register-with-eureka: true
fetch-registry: true
region: region-east
service-url:
zone1: http://localhost:8761/eureka/,http://localhost:8762/eureka/
zone2: http://localhost:8763/eureka/,http://localhost:8764/eureka/
availability-zones:
region-east: zone1,zone2
server:
waitTimeInMsWhenSyncEmpty: 0
enableSelfPreservation: false這裡值得解釋的是
上面我配置的是四個節點，分別在一個區域裡，用region: region-east 配置，然後這個區域有兩個空間分別是zone1和zone2
availability-zones:
region-east: zone1,zone2
這個配置代表了然後8761和8762在zone1空間裡，8763和8764在zone2空間裡，請大家仔細看我上面的配置，按照配置理解用意。
還有必要解釋的是WaitTimeInMsWhenSyncEmpty(*)：
這個設定為0是為了儘快讓eureka server啟動起來就提供rest api服務。預設是5分鐘，也就是如果peer節點註冊列表為空，那就等5分鐘讓其他服務有註冊上來了，然後同步過來，再對外提供rest api服務。
UseReadOnlyResponseCache（*）：
目前採用的是二級快取策略，一個是讀寫快取記憶體過期策略，另一個沒有過期只有只讀快取，預設為true，表示只讀快取。
然後進入eureka-server目錄下分別執行
mvn spring-boot:run -Dspring.profiles.active=zone1a
mvn spring-boot:run -Dspring.profiles.active=zone1b
mvn spring-boot:run -Dspring.profiles.active=zone2a
mvn spring-boot:run -Dspring.profiles.active=zone1b
切記每次執行下一條命令需要再開啟一個Terminal
這裡筆者全部啟動成功了。其實這時候你們訪問http://localhost:8761/ 任意節點都是可以看到的。
但是我為了更好說明問題，這裡加入一個eureka-client，並且這個客戶端是雙節點的，分別在zone1和zone2各一個
下面是client的pom和啟動類
<groupId>cn.springcloud.book</groupId>
<artifactId>ch3-2-eureka-client</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>ch3-2-eureka-client</name>
<description>ch3-2-eureka-client</description>
<parent>
<groupId>cn.springcloud.book</groupId>
<artifactId>ch3-2</artifactId>
<version>0.0.1-SNAPSHOT</version>
<relativePath>../pom.xml</relativePath> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>@SpringBootApplication
@EnableDiscoveryClient
public class Ch32EurekaClientApplication {
public static void main(String[] args) {
SpringApplication.run(Ch32EurekaClientApplication.class, args);
}
}下面我同樣分別列出client的配置檔案
management:
endpoints:
web:
exposure:
include: '*'server:
port: 8081
spring:
application:
name: client
eureka:
instance:
metadataMap.zone: zone1
client:
register-with-eureka: true
fetch-registry: true
region: region-east
service-url:
zone1: http://localhost:8761/eureka/,http://localhost:8762/eureka/
zone2: http://localhost:8763/eureka/,http://localhost:8764/eureka/
availability-zones:
region-east: zone1,zone2
server:
port: 8082
spring:
application:
name: client
eureka:
instance:
metadataMap.zone: zone2
client:
register-with-eureka: true
fetch-registry: true
region: region-east
service-url:
zone1: http://localhost:8761/eureka/,http://localhost:8762/eureka/
zone2: http://localhost:8763/eureka/,http://localhost:8764/eureka/
availability-zones:
region-east: zone1,zone2
下面分別用命令啟動兩個節點，操作也是和eurekaServer是一樣的，進入到client目錄
分別使用mvn spring-boot:run -Dspring.profiles.active=zone1 和mvn spring-boot:run -Dspring.profiles.active=zone2
大家可以四個節點都訪問以下，展示的頁面和這一個是一樣的。
好了，到這裡已經講解完多節點配置和應用了，
下面如果把這兩個工程打成jar在伺服器上分別啟動不同配置檔案jar的時候
用java -Dspring.profiles.active=prod -jar xxx.jar 命令
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