Docker下redis与springboot三部曲之三:springboot下访问redis哨兵

2018-01-17 10:31:04来源:http://blog.csdn.net/boling_cavalry/article/details/79041129作者:CSDN博客人点击

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在 《 Docker下redis与springboot三部曲之二:安装redis主从和哨兵》 一文中,我们在docker下搭建了redis主从和哨兵,本章我们开发一个基于springboot的web工程,体验springboot下如何使用redis高可用服务;


原文地址: http://blog.csdn.net/boling_cavalry/article/details/79041129


实战环境
本次实战的环境是Ubuntu16,安装的Docker版本是17.03.2-ce;
本次开发web工程的ide推荐使用IntelliJ IDEA;
本次实战用到的redis服务,在上一次实战中已经搭建完成,详情请参照在 《 Docker下redis与springboot三部曲之二:安装redis主从和哨兵》 ;
哨兵的数量为三个,由于之前已经配置了QUORUM=2,如果哨兵只有一个,在master出了问题重新选举master的时候,会因为投票数不够一半导致选举失败,无法将slave切换为master;
容器运行情况如下:
root@rabbitmq:/usr/local/work/blog# docker ps
CONTAINER IDIMAGECOMMANDCREATEDSTATUSPORTSNAMES
39369dd41b45bolingcavalry/redis3sentinel:0.0.1 "sentinel-entrypoi..." About a minute ago Up About a minute 6379/tcp, 26379/tcpblog_sentinel_2
2c319d8cd473bolingcavalry/redis3sentinel:0.0.1 "sentinel-entrypoi..." About a minute ago Up About a minute 6379/tcp, 26379/tcpblog_sentinel_3
9c2ddac0d1fbredis:3"docker-entrypoint..." About a minute ago Up About a minute 6379/tcp blog_slave_2
d6fbcf0db3fdbolingcavalry/springbootrun:0.0.1"/bin/bash"2 minutes agoUp 2 minutes0.0.0.0:8080->8080/tcp blog_java_1
5f889da820a1bolingcavalry/redis3sentinel:0.0.1 "sentinel-entrypoi..." 2 minutes agoUp 2 minutes6379/tcp, 26379/tcpblog_sentinel_1
b54d6373a65eredis:3"docker-entrypoint..." 2 minutes agoUp 2 minutes6379/tcp blog_slave_1
2b7b3b80af56redis:3"docker-entrypoint..." 2 minutes agoUp 2 minutes6379/tcp blog_master_1
73b4044c420dredis:3"docker-entrypoint..." 2 minutes agoUp 2 minutes6379/tcp blog_client_1
redis环境

我们先回顾一下docker-compose.yml的内容,看看已经准备好哪些服务了:


master:
image: redis:3
ports:
- "6379:6379"
slave:
image: redis:3
command: redis-server --slaveof redis-master 6379
links:
- master:redis-master
sentinel:
image: bolingcavalry/redis3sentinel:0.0.1
environment:
- SENTINEL_DOWN_AFTER=5000
- SENTINEL_FAILOVER=5000
links:
- master:redis-master
- slave
ports:
- "26379:26379"
java:
image: bolingcavalry/springbootrun:0.0.1
links:
- sentinel:redis-sentinel
- master:redis-master
volumes:
- /usr/local/work/share:/usr/Downloads
ports:
- "8080:8080"
tty:true
client:
image: redis:3

上面的java服务有以下几点请注意:


1. 这个服务已经配置了两个link参数,由此在这个容器中redis-sentinel就代表了哨兵的地址,redis-master就代表了master的地址(/etc/hosts的配置效果);


2. 使用的镜像是bolingcavalry/springbootrun:0.0.1,这是我做的镜像,功能非常简单:装了JDK,暴露了8080端口,详情请看 《Docker下运行springboot》 ;


3. 容器的/usr/local/work/share与当前电脑的/usr/Downloads目录已建立映射关系,把文件放到/usr/Downloads目录,就相当于把文件放入了容器的/usr/local/work/share目录;


4. 容器的8080端口与当前电脑的8080端口绑定;


5. 使用tty参数分配终端,否则容器启动后会立即退出;


web工程源码

web工程源码我已上传到github,地址是:git@github.com:zq2599/blog_demos.git,或者用浏览器访问: https://github.com/zq2599/blog_demos ,这里面有多个工程,本次实战的工程是redissentineldemo,如下图红框所示:



pom.xml

本次实战的web工程是基于maven构建的,pom.xml的内容与通常的spring boot工程一样,只有依赖库新增以下内容:


<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

如上所示,增加了spring-boot-starter-data-redis;


application.properties(连接master)

配置文件application.properties的内容如下:


spring.redis.database=0
spring.redis.host=redis-master
spring.redis.port=6379
spring.redis.pool.max-active=2500
spring.redis.pool.max-wait=6000
spring.redis.pool.max-idle=500
spring.redis.pool.min-idle=100
spring.redis.pool.testOnBorrow=true
spring.redis.pool.blockWhenExhausted=true
spring.redis.pool.numTestsPerEvictionRun=3
spring.redis.pool.timeBetweenEvictionRunsMillis=-1
spring.redis.timeout=100

spring.redis.host和spring.redis.port表明这个配置文件是直接连接master库的;


源码

在springboot下操作redis的步骤很简单,这里做了一个controller来验证写redis,代码如下:


@RestController
public class MockController {
@Autowired
private StringRedisTemplate stringRedisTemplate;
@RequestMapping(value = "/testredis/{key}/{value}", method = RequestMethod.GET)
@ResponseBody
public String testRedis(@PathVariable("key") final String key, @PathVariable("value") final String value) {
try{
stringRedisTemplate.opsForValue().set(key, value);
}catch(Exception e){
e.printStackTrace();
}
return "1. success";
}
}

如上所示,spring环境会根据配置信息来初始化StringRedisTemplate对象,我们只要通过@Autowire注解配置就能直接使用了;


验证

将上述工程打包成jar,放入blog_java_1容器(之前提到过文件夹映射的),再执行命令java -jar redissentineldemo-0.0.1-SNAPSHOT.jar启动服务;


我当前电脑的IP是192.168.119.155,所以在浏览器访问: http://192.168.119.155:8080/testredis/name/tom111112333666777 ,浏览器会显示”“1. success”,此时controller会在redis中写入key为”name”,value为”tom111112333666777”的一条记录;


执行命令docker exec -it blog_slave_1 /bin/bash进入slave的容器,查看”name”对应的值,如下所示:


root@362d09f7fee9:/data# redis-cli
127.0.0.1:6379> get name
"tom111112333666777"
127.0.0.1:6379>

可见从库已经同步到了主库写入的数据;


web工程连接到哨兵

前面的实战我们是直接连接到redis的master,并未体验到哨兵带来的高可用能力,现在我们来试试连接到哨兵,这样当master有问题时,如果slave成了新的master,应用程序不需要任何改动,通过哨兵就能自动连接到新的master;


application.properties(连接哨兵)

从连接到master改为连接到哨兵的改动很简单,只需要修改配置文件即可,修改后的application.properties的内容如下:


spring.redis.database=0
#spring.redis.host=redis-master
#spring.redis.port=6379
spring.redis.pool.max-active=2500
spring.redis.pool.max-wait=6000
spring.redis.pool.max-idle=500
spring.redis.pool.min-idle=100
spring.redis.pool.testOnBorrow=true
spring.redis.pool.blockWhenExhausted=true
spring.redis.pool.numTestsPerEvictionRun=3
spring.redis.pool.timeBetweenEvictionRunsMillis=-1
spring.redis.sentinel.master=mymaster
spring.redis.sentinel.nodes=redis-sentinel:26379
spring.redis.timeout=1000

可见spring.redis.host和spring.redis.port这两个配置被注释掉,然后新增了spring.redis.sentinel.master和spring.redis.sentinel.nodes,“redis-sentinel”是link参数,可以连接到哨兵的机器;


以上就是所有改动,重新打包复制到blog_java_1容器,启动后在浏览器发起一次请求,然后去redis服务器上检查,发现数据成功更新;


验证高可用
执行命令令docker stop blog_master_1停止master容器,再docker logs -f blog_sentinel_1命令查看哨兵日志,可以发现slave已经切换成了master,如下:
root@rabbitmq:~# docker stop blog_master_1
blog_master_1
root@rabbitmq:/usr/local/work/blog# docker logs -f blog_sentinel_1
_._
_.-``__ ''-._
_.-```.`_.''-._ Redis 3.2.11 (00000000/0) 64 bit
.-`` .-```.```//_.,_ ''-._
(', .-`| `,) Running in sentinel mode
|`-._`-...-` __...-.``-._|'` _.-'| Port: 26379
|`-._ `._/ _.-'| PID: 1
`-._`-._`-./_.-'_.-'
|`-._`-._`-.__.-'_.-'_.-'|
|`-._`-.__.-'_.-'| http://redis.io
`-._`-._`-.__.-'_.-'_.-'
|`-._`-._`-.__.-'_.-'_.-'|
|`-._`-.__.-'_.-'|
`-._`-._`-.__.-'_.-'_.-'
`-._`-.__.-'_.-'
`-.__.-'
`-.__.-'
1:X 12 Jan 12:31:46.811 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
1:X 12 Jan 12:31:46.812 # Sentinel ID is 43a5934ce2c884b268e40cfbb3d3e14bb3d7bac3
1:X 12 Jan 12:31:46.812 # +monitor master mymaster 172.17.0.3 6379 quorum 2
1:X 12 Jan 12:31:46.812 * +slave slave 172.17.0.4:6379 172.17.0.4 6379 @ mymaster 172.17.0.3 6379
1:X 12 Jan 12:31:56.923 * +fix-slave-config slave 172.17.0.4:6379 172.17.0.4 6379 @ mymaster 172.17.0.3 6379
1:X 12 Jan 12:32:13.463 * +sentinel sentinel 6f85d8262413edc32ce2a996cbbaf6d8bfc27563 172.17.0.8 26379 @ mymaster 172.17.0.3 6379
1:X 12 Jan 12:32:13.469 * +sentinel sentinel ba786641ce23a03f0d6cff8885d6315edf025d43 172.17.0.7 26379 @ mymaster 172.17.0.3 6379
1:X 12 Jan 12:32:16.886 * +slave slave 172.17.0.9:6379 172.17.0.9 6379 @ mymaster 172.17.0.3 6379
1:X 12 Jan 12:32:26.997 * +fix-slave-config slave 172.17.0.9:6379 172.17.0.9 6379 @ mymaster 172.17.0.3 6379
1:X 12 Jan 12:35:28.735 # +sdown master mymaster 172.17.0.3 6379
1:X 12 Jan 12:35:28.805 # +new-epoch 1
1:X 12 Jan 12:35:28.805 # +vote-for-leader 6f85d8262413edc32ce2a996cbbaf6d8bfc27563 1
1:X 12 Jan 12:35:29.812 # +odown master mymaster 172.17.0.3 6379 #quorum 3/2
1:X 12 Jan 12:35:29.812 # Next failover delay: I will not start a failover before Fri Jan 12 12:35:39 2018
1:X 12 Jan 12:35:30.004 # +config-update-from sentinel 6f85d8262413edc32ce2a996cbbaf6d8bfc27563 172.17.0.8 26379 @ mymaster 172.17.0.3 6379
1:X 12 Jan 12:35:30.004 # +switch-master mymaster 172.17.0.3 6379 172.17.0.4 6379
1:X 12 Jan 12:35:30.004 * +slave slave 172.17.0.9:6379 172.17.0.9 6379 @ mymaster 172.17.0.4 6379
1:X 12 Jan 12:35:30.004 * +slave slave 172.17.0.3:6379 172.17.0.3 6379 @ mymaster 172.17.0.4 6379
1:X 12 Jan 12:35:35.025 # +sdown slave 172.17.0.3:6379 172.17.0.3 6379 @ mymaster 172.17.0.4 6379

如上日志所示,“+new-epoch 1”表示发起了新的选举,“+odown master mymaster 172.17.0.3 6379 #quorum 3/2”表示投票超过了一半,选举成功,slave被选为master;


这里要注意的是,quorum参数在conf中被我们配置成了2,所以这里要有三个哨兵才能投票通过,如果您没有执行命令docker-compose scale sentinel=3将哨兵数量扩展为3,slave是不会切换成master的!


像前面的验证方式一样,在浏览器发起一次请求( http://192.168.119.155:8080/testredis/name/aaabbbccc ),然后去slave服务器上执行redis-cli进入控制台检查key为”name”的值,发现数据成功更新为”aaabbbccc”;

至此,《Docker下redis与springboot三部曲》系列实战就全部完成了,希望能帮助你熟悉和了解redis的一些特性,以及基本的java调用redis服务的操作。


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