C#两大知名Redis客户端连接哨兵集群的姿势

前言

前面《Docker-Compose搭建Redis高可用哨兵集群》，
我的思路是将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, 但实际上并不是最常规做法。

Redis Client App独立组网遇到的问题

很多时候，Redis Client App与Redis-Sentinel独立组网，这样对Redis-Sentinel的访问就会涉及Docker宿主机NAT转换、Port映射。

(这里我们就不提Docker Host模式搭建Redis-Sentinel了)

资料显示 Sentinel,Docker或其他形式的网络地址转换或端口映射应谨慎混合，大意是说节点无法区分收到的信息是否是已经发生Nat转换或端口映射的结果。

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转换、Port映射。

C#两大客户端访问Redis-Sentinel的方式

归根到底一张图：

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

Docker部署Redis-Sentinel 并强制声明IP、Port

这里我们采用主动声明方式在Docker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，很早就支持连接哨兵，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-Sentinelpublic  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 masterConfigurationOptions 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($"[Use StackExchange-Redis] The remote redis-sentinel test key value:{value}");}// CSRedisCore连接Redis-Sentinelpublic static  void UseCSRedisCore(){var csredis = new CSRedis.CSRedisClient("mymaster1,password=redis_pwd",new[] { "180.76.*.*:26379", "180.76.*.*:26380", "180.76.*.*:26381" });var value = csredis.Get("testKey");Console.WriteLine($"[Use CSRedisCore] The remote redis-sentinel test key value:{value}");}}
}

执行输出：