C#两大知名Redis客户端连接哨兵集群的姿势

时间:2024-01-26 18:33:20

前言

前面利用《Docker-Compose搭建Redis高可用哨兵集群》,
我们的思路是将Redis、Sentinel、Redis Client App链接到同一个网桥网络,这个网桥内的Redis Client App就可以使用ContainerIP访问网桥内任意redis节点。

同一网桥网络访问规避了Docker上发生的NAT,端口映射的复杂性, 但实际上并不是常规实践

Redis Client App独立组网遇到的问题

很多时候,Redis-Sentinel与Redis Client App独立组网,涉及Docker宿主机NAT转换和 Port映射。

Sentinel,Docker或其他形式的网络地址转换或端口映射应谨慎混合。
我实际测试发现,如果将前文Sentinel.conf中Master(ContainerIP,Port) 换成(宿主机IP,映射Port),
确实会引起混乱,无法找到正确的Slaves, 无法正常故障转移。

为了解决Redis-Sentinel在Docker环境下因为NAT,Forward Port导致的无法正确获知Slaves和正确故障转移的问题。
Redis3.2之后可以强制让Slave声明自己的(IP,Port);强制让Sentinel声明自己的(IP,Port)

 # since Redis 3.2.2, to force a replica to announce an arbitrary pair of IP and port to the master. The two configurations directives to use are:
replica-announce-ip <ip>
replica-announce-port <port>

上述配置可以写在Docker Command参数指定或通过Volume redis.conf 加载进redis容器

# you can use the following two Sentinel configuration directives in order to force Sentinel to announce a specific set of IP and port:

sentinel announce-ip <ip>
sentinel announce-port <port>

sentinel.conf的配置只能通过Config加载进sentinel容器。

通过明牌方式通知 所有交互对象,redis实例就是在这个(IP,Port)上发生了NAT转化,Port映射,上述搭建Docker搭建Redis-sentinel才是常规实践。

C#两大客户端访问Redis-Sentinel的方式

归根到底一张图:

  1. Redis Client先询问Sentinels,Sentinel返回Master (IP,Port)
  2. Redis Client再与以上Master (IP,Port)建立连接

Redis-Sentinel

这里我们采用Docker-compose在单机上部署了Redis-Sentinel集群,
1Master- 2 Slave- 3Sentinel,
分别占据宿主机6380、6381、6382、 26379、26380、26381端口.

CONTAINER ID        IMAGE                          COMMAND                  CREATED             STATUS                  PORTS                                NAMES
484da8d832f1        redis                          "docker-entrypoint.s…"   2 hours ago         Up 2 hours              6379/tcp, 0.0.0.0:26380->26379/tcp   redis-sentinel-2
50599c15adba        redis                          "docker-entrypoint.s…"   2 hours ago         Up 2 hours              6379/tcp, 0.0.0.0:26379->26379/tcp   redis-sentinel-1
51ce90cc52d7        redis                          "docker-entrypoint.s…"   2 hours ago         Up 2 hours              6379/tcp, 0.0.0.0:26381->26379/tcp   redis-sentinel-3
d58d6973de28        redis                          "docker-entrypoint.s…"   2 hours ago         Up 2 hours              0.0.0.0:6381->6379/tcp               redis-slave-1
b88bd85ac109        redis                          "docker-entrypoint.s…"   2 hours ago         Up 8 seconds            0.0.0.0:6382->6379/tcp               redis-slave-2
3dc26c01a90d        redis                          "docker-entrypoint.s…"   2 hours ago         Up About an hour        0.0.0.0:6380->6379/tcp               redis-master


进入任意Sentinel节点,使用sentinel master mymaster确认集群信息

存在测试键值: testKey:hello Redis-sentinel!

StackExchange.Redis & CSRedisCore连接Redis哨兵

老牌StackExchange.Redis 今年才真正支持Sentinel, Github上有关Sentinel的Issue、PR历时久远,PR像便秘一样最近才关闭。
https://github.com/StackExchange/StackExchange.Redis/pull/692#issuecomment-375298108
https://github.com/StackExchange/StackExchange.Redis/pull/1067

CSRedisCore得到真传,很早就支持了,而且编程写法更简单,清晰。

话不多说:

using StackExchange.Redis;
using System;

namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            var sw = new Stopwatch();
            sw.Start();
            UseStackExchangeRedis();  
            sw.Stop();
            Console.WriteLine("连接+查询测试key,耗时"+sw.ElapsedMilliseconds);

            sw.Reset();
            sw.Start();
            UseCSRedisCore();
            sw.Stop();
            Console.WriteLine("连接+查询测试key,耗时" + sw.ElapsedMilliseconds);
            Console.ReadKey();
        }
       // StackExchange.Reids连接Redis-Sentinel
        public  static void  UseStackExchangeRedis()
        {
            ConfigurationOptions sentinelOptions = new ConfigurationOptions();
            sentinelOptions.EndPoints.Add("180.76.*.*", 26379);
            sentinelOptions.EndPoints.Add("180.76.*.*", 26380);
            sentinelOptions.EndPoints.Add("180.76.*.*", 26381);
            sentinelOptions.TieBreaker = "";
            sentinelOptions.CommandMap = CommandMap.Sentinel;
            sentinelOptions.AbortOnConnectFail = false;
            // Connect!
            ConnectionMultiplexer sentinelConnection = ConnectionMultiplexer.Connect(sentinelOptions);

            // Get a connection to the master
            ConfigurationOptions redisServiceOptions = new ConfigurationOptions();
            redisServiceOptions.ServiceName = "mymaster1";   //master名称
            redisServiceOptions.Password = "redis_pwd";     //master访问密码
            redisServiceOptions.AbortOnConnectFail = true;
            ConnectionMultiplexer masterConnection = sentinelConnection.GetSentinelMasterConnection(redisServiceOptions);

            var db  = masterConnection.GetDatabase();
            var value= db.StringGet("testKey");
            Console.WriteLine($"[Use StackExchange-Redis] The remote redis-sentinel test key value:{value}");
        }

    // CSRedisCore连接Redis-Sentinel
        public static  void UseCSRedisCore()
        {
            var csredis = new CSRedis.CSRedisClient("mymaster1,password=redis_pwd",
                    new[] { "180.76.*.*:26379", "180.76.*.*:26380", "180.76.*.*:26381" });
            var value = csredis.Get("testKey");
            Console.WriteLine($"[Use CSRedisCore] The remote redis-sentinel test key value:{value}");
        }
    }
}

执行输出:

本文长话短说,快速介绍两块C#常见的Redis客户端连接Redis哨兵集群的方式,各有千秋。
StackExchange.Redis更能体现连接的实质过程: 先查询,再连接。
CSRedisCore 小白写法,无感知。

Gthub地址:https://github.com/zaozaoniao/Redis-sentinel-with-docker-compose

总结输入

本文记录两个内容:

  1. Redis-Sentinel在Docker环境因NAT,Forward_Port触发的问题, 以及Redis官方给出的方案
  2. C#两个Redis客户端如何感知Redis-Sentinel的Master查询节点