一起来学SpringCloud之-高可用服务注册中心(Eureka-Cluster)

文章目录
  1. 1. - Eureka Cluster
    1. 1.1. - pom.xml
    2. 1.2. - Application.java
    3. 1.3. - application.yml
    4. 1.4. - 启动集群
  2. 2. - 高可用测试
    1. 2.1. - pom.xml
    2. 2.2. - application.yml
    3. 2.3. - H2Application.java
    4. 2.4. - 测试
  3. 3. - 注意事项
  4. 4. - 小谈
  5. 5. - 说点什么

在实际生产中,我们需要高可用的集群方案,本章就是基于SpringBoot1.5.4 Cloud(Dalston.SR2) 的高可用Eureka Cluster,以及生产中需要注意的事项…

- Eureka Cluster

本教程用1个项目(battcn-cloud-discovery),多环境方式演示

- pom.xml

1
2
3
4
5
6
7
8
9
10
11
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka-server</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>

- Application.java

1
2
3
4
5
6
7
8
@SpringBootApplication
@EnableEurekaServer
public class BattcnCloudDiscoveryApplication {

public static void main(String[] args) {
SpringApplication.run(BattcnCloudDiscoveryApplication.class, args);
}
}

- application.yml

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
server:
port: 8761
spring:
profiles:
active: peer2
#官方写的就是 8761
---
spring:
profiles: peer1
application:
name: Eureka-Server-1
eureka:
instance:
hostname: peer1
#配置主机名
client:
register-with-eureka: false
#配置服务注册中心是否以自己为客户端进行注册(配置false)
fetch-registry: false
#是否取得注册信息(配置false)
service-url:
defaultZone: http://peer2:7002/eureka/
#defaultZone 一定要按照标准写法,因为service-url的数据类型是Map 这算是个小坑需要注意
server:
port: 7001
---
spring:
profiles: peer2
application:
name: Eureka-Server-1
eureka:
instance:
hostname: peer2
#配置主机名
client:
register-with-eureka: false
#配置服务注册中心是否以自己为客户端进行注册(配置false)
fetch-registry: false
#是否取得注册信息(配置false)
service-url:
defaultZone: http://peer1:7001/eureka/
server:
port: 7002
#defaultZone 一定要按照标准写法,因为service-url的数据类型是Map 这算是个小坑需要注意

- 启动集群

命令:mvn clean package (先打成jar包)

1
2
peer1:java -jar battcn-cloud-discovery.jar --spring.profiles.active=peer1
peer2:java -jar battcn-cloud-discovery.jar --spring.profiles.active=peer2

1.点击蓝色加号
2.点击Spring Boot
3.填写 Name:peer1 Program arguments:–spring.profiles.active=peer1(启动2个操作2次,记得改名字和激活环境,Eclipse太简单了application.yml 直接修改内容启动就行了)

启动多个

启动成功分别访问

1
http://peer1:7001

peer1

1
http://peer2:7002

peer2

如出现上图所示,代表我们集群启动成功

- 高可用测试

1.创建battcn-cloud-h1battcn-cloud-h2 2个项目,基本大同小异

就这2个包够了,跟 h1 代码唯一的区别就是 h2 做调用 h1写好接口就行了

- pom.xml

1
2
3
4
5
6
7
8
9
10
11
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>

- application.yml

1
2
3
4
5
6
7
8
9
10
11
12
server:	
port: 7012
spring:
application:
name: battcn-cloud-h2

eureka:
instance:
hostname: localhost #配置主机名
client:
service-url:
defaultZone: http://peer1:7001/eureka/,http://peer2:7002/eureka/ #配置Eureka Server

- H2Application.java

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
@SpringBootApplication
@EnableDiscoveryClient
@RestController
public class H2Application {

static Logger LOGGER = LoggerFactory.getLogger(H2Application.class);

@Bean
@LoadBalanced
RestTemplate restTemplate() {
return new RestTemplate();
}

@RequestMapping("/h2")
public String home(@RequestParam String email) {
// 改写法之前有说过是VIP模式
return restTemplate().getForObject("http://battcn-cloud-h1/h1?email=" + email, String.class);
}

public static void main(String[] args) {
SpringApplication.run(H2Application.class, args);
}
}

- 测试

分别启动 battcn-cloud-h1battcn-cloud-h2

服务注册

访问:http://localhost:7012/h2?email=1837307557@qq.com

浏览器:My Name's :battcn-cloud-h1 Email:1837307557@qq.com 代表请求成功,然后我们断掉 peer1 或者 peer2 继续请求依旧可用,只是日志会抛异常,通过日志我们可以发现peer2 time out 因为它被杀掉了,但是这并不影响我们服务调用(高可用),只要在启动peer2 错误就不会在出现,在生产中如果集群都挂了 直接 运维下岗就是了(如果peer1 peer2同时挂掉,在启动服务会自动注册上去.)

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
2017-07-31 23:01:03.314 ERROR 14792 --- [-target_peer2-8] c.n.e.cluster.ReplicationTaskProcessor   : Network level connection to peer peer2; retrying after delay

com.sun.jersey.api.client.ClientHandlerException: org.apache.http.conn.ConnectTimeoutException: Connect to peer2:7002 timed out
at com.sun.jersey.client.apache4.ApacheHttpClient4Handler.handle(ApacheHttpClient4Handler.java:187) ~[jersey-apache-client4-1.19.1.jar:1.19.1]
at com.netflix.eureka.cluster.DynamicGZIPContentEncodingFilter.handle(DynamicGZIPContentEncodingFilter.java:48) ~[eureka-core-1.6.2.jar:1.6.2]
at com.netflix.discovery.EurekaIdentityHeaderFilter.handle(EurekaIdentityHeaderFilter.java:27) ~[eureka-client-1.6.2.jar:1.6.2]
at com.sun.jersey.api.client.Client.handle(Client.java:652) ~[jersey-client-1.19.1.jar:1.19.1]
at com.sun.jersey.api.client.WebResource.handle(WebResource.java:682) ~[jersey-client-1.19.1.jar:1.19.1]
at com.sun.jersey.api.client.WebResource.access$200(WebResource.java:74) ~[jersey-client-1.19.1.jar:1.19.1]
at com.sun.jersey.api.client.WebResource$Builder.post(WebResource.java:570) ~[jersey-client-1.19.1.jar:1.19.1]
at com.netflix.eureka.transport.JerseyReplicationClient.submitBatchUpdates(JerseyReplicationClient.java:116) ~[eureka-core-1.6.2.jar:1.6.2]
at com.netflix.eureka.cluster.ReplicationTaskProcessor.process(ReplicationTaskProcessor.java:71) ~[eureka-core-1.6.2.jar:1.6.2]
at com.netflix.eureka.util.batcher.TaskExecutors$BatchWorkerRunnable.run(TaskExecutors.java:187) [eureka-core-1.6.2.jar:1.6.2]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_60]
Caused by: org.apache.http.conn.ConnectTimeoutException: Connect to peer2:7002 timed out
at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:123) ~[httpclient-4.5.3.jar:4.5.3]
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:180) ~[httpclient-4.5.3.jar:4.5.3]
at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:144) ~[httpclient-4.5.3.jar:4.5.3]
at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:134) ~[httpclient-4.5.3.jar:4.5.3]
at org.apache.http.impl.client.DefaultRequestDirector.tryConnect(DefaultRequestDirector.java:610) ~[httpclient-4.5.3.jar:4.5.3]
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:445) ~[httpclient-4.5.3.jar:4.5.3]
at org.apache.http.impl.client.AbstractHttpClient.doExecute(AbstractHttpClient.java:835) ~[httpclient-4.5.3.jar:4.5.3]
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:118) ~[httpclient-4.5.3.jar:4.5.3]
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:56) ~[httpclient-4.5.3.jar:4.5.3]
at com.sun.jersey.client.apache4.ApacheHttpClient4Handler.handle(ApacheHttpClient4Handler.java:173) ~[jersey-apache-client4-1.19.1.jar:1.19.1]
... 10 common frames omitted

- 注意事项

EurekaClientConfigBean.java 默认构造方法,如果serviceUrl.defaultZone = null 那么 就注册到 http://localhost:8761/eureka/ 中去(日志会输出改地址,起初我是看的一脸懵逼),所以其他的Key都可以以 杠(-) 或者全大写方式,该处不行,因为人家源码是Map不是对象

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
public EurekaClientConfigBean() {
this.serviceUrl.put("defaultZone", "http://localhost:8761/eureka/");
this.gZipContent = true;
this.useDnsForFetchingServiceUrls = false;
this.registerWithEureka = true;
this.preferSameZoneEureka = true;
this.availabilityZones = new HashMap();
this.filterOnlyUpInstances = true;
this.fetchRegistry = true;
this.dollarReplacement = "_-";
this.escapeCharReplacement = "__";
this.allowRedirects = false;
this.onDemandUpdateStatusChange = true;
this.clientDataAccept = EurekaAccept.full.name();
}

public String[] getAvailabilityZones(String region) {
String value = (String)this.availabilityZones.get(region);
if(value == null) {
value = "defaultZone";
}

return value.split(",");
}

public List<String> getEurekaServerServiceUrls(String myZone) {
String serviceUrls = (String)this.serviceUrl.get(myZone);
if(serviceUrls == null || serviceUrls.isEmpty()) {
serviceUrls = (String)this.serviceUrl.get("defaultZone");
}

if(!StringUtils.isEmpty(serviceUrls)) {
String[] serviceUrlsSplit = StringUtils.commaDelimitedListToStringArray(serviceUrls);
List<String> eurekaServiceUrls = new ArrayList(serviceUrlsSplit.length);
String[] var5 = serviceUrlsSplit;
int var6 = serviceUrlsSplit.length;

for(int var7 = 0; var7 < var6; ++var7) {
String eurekaServiceUrl = var5[var7];
if(!this.endsWithSlash(eurekaServiceUrl)) {
eurekaServiceUrl = eurekaServiceUrl + "/";
}

eurekaServiceUrls.add(eurekaServiceUrl);
}

return eurekaServiceUrls;
} else {
return new ArrayList();
}
}

- 小谈

其实我是比较倾向于 consul 这种零侵入式的,但是consul 在做高可用比较操蛋,它对外暴露的是 agent 如果你这个 agent挂了,那么后面服务就GG思密达了,cloud service 不允许配置多个agent,个人没找到好的解决方案,有好方案的可以交流…..

- 说点什么

微信公众号:battcn(欢迎调戏)

本章代码(Eureka-Cluster):https://git.oschina.net/battcn/battcn-cloud/tree/master/battcn-cloud-discovery

本章代码(Client-H1/H2):https://git.oschina.net/battcn/battcn-cloud/tree/master/battcn-cloud-discovery-cluster-test

如有问题请及时与我联系

  • 个人QQ:1837307557
  • Spring Cloud中国社区①:415028731
  • Spring For All 社区⑤:157525002