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
代码语言：javascript复制# 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.
代码语言：javascript复制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：
代码语言：javascript复制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：
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。
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# Redis客户端连接Redis-Sentinel集群
Gthub：https://github.com/zaozaoniao/Redis-sentinel-with-docker-compose
- https://redis.io/topics/sentinel
- https://redis.io/topics/replication
