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这篇文章主要介绍 Redis 集群的示例分析，文中介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们一定要看完！
Redis 集群详解
Redis 有三种集群模式，分别是：
* 主从模式
* Sentinel 模式
* Cluster 模式三种集群模式各有特点，关于 Redis 介绍可以参考这里：NoSQL（二)——Redis
Redis 官网：https://redis.io/，最新版本 5.0.4
主从模式
主从模式介绍
主从模式是三种模式中最简单的，在主从复制中，数据库分为两类：主数据库 (master) 和从数据库(slave)。
其中主从复制有如下特点：
* 主数据库可以进行读写操作，当读写操作导致数据变化时会自动将数据同步给从数据库
* 从数据库一般都是只读的，并且接收主数据库同步过来的数据
* 一个 master 可以拥有多个 slave，但是一个 slave 只能对应一个 master
* slave 挂了不影响其他 slave 的读和 master 的读和写，重新启动后会将数据从 master 同步过来
* master 挂了以后，不影响 slave 的读，但 redis 不再提供写服务，master 重启后 redis 将重新对外提供写服务
* master 挂了以后，不会在 slave 节点中重新选一个 master工作机制：
当 slave 启动后，主动向 master 发送 SYNC 命令。master 接收到 SYNC 命令后在后台保存快照（RDB 持久化）和缓存保存快照这段时间的命令，然后将保存的快照文件和缓存的命令发送给 slave。slave 接收到快照文件和命令后加载快照文件和缓存的执行命令。
复制初始化后，master 每次接收到的写命令都会同步发送给 slave，保证主从数据一致性。
安全设置：
当 master 节点设置密码后，
客户端访问 master 需要密码
启动 slave 需要密码，在配置文件中配置即可
客户端访问 slave 不需要密码缺点：
从上面可以看出，master 节点在主从模式中唯一，若 master 挂掉，则 redis 无法对外提供写服务。
主从模式搭建
环境准备：
master 节点 192.168.30.128
slave 节点 192.168.30.129
slave 节点 192.168.30.130全部下载安装：
# cd /software# wget http://download.redis.io/releases/redis-5.0.4.tar.gz# tar zxf redis-5.0.4.tar.gz mv redis-5.0.4/ /usr/local/redis# cd /usr/local/redis make make install# echo $?0全部配置成服务：
服务文件
# vim /usr/lib/systemd/system/redis.service[Unit]Description=Redis persistent key-value database
After=network.target
After=network-online.target
Wants=network-online.target[Service]ExecStart=/usr/local/bin/redis-server /usr/local/redis/redis.conf --supervised systemd
ExecStop=/usr/libexec/redis-shutdown
Type=notify
User=redis
Group=redis
RuntimeDirectory=redis
RuntimeDirectoryMode=0755[Install]WantedBy=multi-user.targetshutdown 脚本
# vim /usr/libexec/redis-shutdown#!/bin/bash## Wrapper to close properly redis and sentineltest x $REDIS_DEBUG != x set -x
REDIS_CLI=/usr/local/bin/redis-cli# Retrieve service nameSERVICE_NAME= $1 if [ -z $SERVICE_NAME ]; then
SERVICE_NAME=redisfi# Get the proper config file based on service nameCONFIG_FILE= /usr/local/redis/$SERVICE_NAME.conf # Use awk to retrieve host, port from config fileHOST=`awk /^[[:blank:]]*bind/ { print $2 } $CONFIG_FILE | tail -n1`PORT=`awk /^[[:blank:]]*port/ { print $2 } $CONFIG_FILE | tail -n1`PASS=`awk /^[[:blank:]]*requirepass/ { print $2 } $CONFIG_FILE | tail -n1`SOCK=`awk /^[[:blank:]]*unixsocket\s/ { print $2 } $CONFIG_FILE | tail -n1`# Just in case, use default host, portHOST=${HOST:-127.0.0.1}if [ $SERVICE_NAME = redis ]; then
PORT=${PORT:-6379}else
PORT=${PORT:-26739}fi# Setup additional parameters# e.g password-protected redis instances[ -z $PASS ] || ADDITIONAL_PARAMS= -a $PASS # shutdown the service properlyif [ -e $SOCK ] ; then
$REDIS_CLI -s $SOCK $ADDITIONAL_PARAMS shutdownelse
$REDIS_CLI -h $HOST -p $PORT $ADDITIONAL_PARAMS shutdownfi# chmod +x /usr/libexec/redis-shutdown# useradd -s /sbin/nologin redis# chown -R redis:redis /usr/local/redis# chown -R redis:redis /data/redis# yum install -y bash-completion source /etc/profile # 命令补全 # systemctl daemon-reload# systemctl enable redis修改配置：
192.168.30.128
# mkdir -p /data/redis# vim /usr/local/redis/redis.confbind 192.168.30.128 #监听 ip，多个 ip 用空格分隔 daemonize yes # 允许后台启动 logfile /usr/local/redis/redis.log #日志路径 dir /data/redis #数据库备份文件存放目录 masterauth 123456 #slave 连接 master 密码，master 可省略 requirepass 123456 #设置 master 连接密码，slave 可省略 appendonly yes # 在 /data/redis/ 目录生成 appendonly.aof 文件，将每一次写操作请求都追加到 appendonly.aof 文件中 # echo vm.overcommit_memory=1 /etc/sysctl.conf# sysctl -p192.168.30.129
# mkdir -p /data/redis# vim /usr/local/redis/redis.confbind 192.168.30.129
daemonize yeslogfile /usr/local/redis/redis.log dir /data/redis
replicaof 192.168.30.128 6379
masterauth 123456
requirepass 123456
appendonly yes# echo vm.overcommit_memory=1 /etc/sysctl.conf# sysctl -p192.168.30.130
# mkdir -p /data/redis# vim /usr/local/redis/redis.confbind 192.168.30.130
daemonize yeslogfile /usr/local/redis/redis.log dir /data/redis
replicaof 192.168.30.128 6379
masterauth 123456
requirepass 123456
appendonly yes# echo vm.overcommit_memory=1 /etc/sysctl.conf# sysctl -p全部启动 redis：
# systemctl start redis查看集群状态：
# redis-cli -h 192.168.30.128 -a 123456Warning: Using a password with -a or -u option on the command line interface may not be safe.
192.168.30.128:6379 info replication# Replicationrole:master
connected_slaves:2
slave0:ip=192.168.30.129,port=6379,state=online,offset=168,lag=1
slave1:ip=192.168.30.130,port=6379,state=online,offset=168,lag=1
master_replid:fb4941e02d5032ad74c6e2383211fc58963dbe90
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:168
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:168# redis-cli -h 192.168.30.129 -a 123456 info replicationWarning: Using a password with -a or -u option on the command line interface may not be safe.# Replicationrole:slave
master_host:192.168.30.128
master_port:6379
master_link_status:up
master_last_io_seconds_ago:1
master_sync_in_progress:0
slave_repl_offset:196
slave_priority:100
slave_read_only:1
connected_slaves:0
master_replid:fb4941e02d5032ad74c6e2383211fc58963dbe90
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:196
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:196数据演示：
192.168.30.128:6379 keys *(empty list or set)192.168.30.128:6379 set key1 100
192.168.30.128:6379 set key2 lzx
192.168.30.128:6379 keys *
1) key1 2) key2# redis-cli -h 192.168.30.129 -a 123456Warning: Using a password with -a or -u option on the command line interface may not be safe.
192.168.30.129:6379 keys *
1) key2 2) key1 192.168.30.129:6379 CONFIG GET dir1) dir 2) /data/redis 192.168.30.129:6379 CONFIG GET dbfilename
1) dbfilename 2) dump.rdb 192.168.30.129:6379 get key1 100 192.168.30.129:6379 get key2 lzx 192.168.30.129:6379 set key3 aaa(error) READONLY You can t write against a read only replica.# redis-cli -h 192.168.30.130 -a 123456Warning: Using a password with -a or -u option on the command line interface may not be safe.
192.168.30.130:6379 keys *
1) key2 2) key1 192.168.30.130:6379 CONFIG GET dir1) dir 2) /data/redis 192.168.30.130:6379 CONFIG GET dbfilename
1) dbfilename 2) dump.rdb 192.168.30.130:6379 get key1 100 192.168.30.130:6379 get key2 lzx 192.168.30.130:6379 set key3 aaa(error) READONLY You can t write against a read only replica.可以看到，在 master 节点写入的数据，很快就同步到 slave 节点上，而且在 slave 节点上无法写入数据。
Sentinel 模式 Sentinel 模式介绍
主从模式的弊端就是不具备高可用性，当 master 挂掉以后，Redis 将不能再对外提供写入操作，因此 sentinel 应运而生。
sentinel 中文含义为哨兵，顾名思义，它的作用就是监控 redis 集群的运行状况，特点如下：
* sentinel 模式是建立在主从模式的基础上，如果只有一个 Redis 节点，sentinel 就没有任何意义
* 当 master 挂了以后，sentinel 会在 slave 中选择一个做为 master，并修改它们的配置文件，其他 slave 的配置文件也会被修改，比如 slaveof 属性会指向新的 master
* 当 master 重新启动后，它将不再是 master 而是做为 slave 接收新的 master 的同步数据
* sentinel 因为也是一个进程有挂掉的可能，所以 sentinel 也会启动多个形成一个 sentinel 集群
* 多 sentinel 配置的时候，sentinel 之间也会自动监控
* 当主从模式配置密码时，sentinel 也会同步将配置信息修改到配置文件中，不需要担心
* 一个 sentinel 或 sentinel 集群可以管理多个主从 Redis，多个 sentinel 也可以监控同一个 redis
* sentinel 最好不要和 Redis 部署在同一台机器，不然 Redis 的服务器挂了以后，sentinel 也挂了工作机制：
* 每个 sentinel 以每秒钟一次的频率向它所知的 master，slave 以及其他 sentinel 实例发送一个 PING 命令
* 如果一个实例距离最后一次有效回复 PING 命令的时间超过 down-after-milliseconds 选项所指定的值， 则这个实例会被 sentinel 标记为主观下线。
* 如果一个 master 被标记为主观下线，则正在监视这个 master 的所有 sentinel 要以每秒一次的频率确认 master 的确进入了主观下线状态
* 当有足够数量的 sentinel（大于等于配置文件指定的值）在指定的时间范围内确认 master 的确进入了主观下线状态， 则 master 会被标记为客观下线
* 在一般情况下， 每个 sentinel 会以每 10 秒一次的频率向它已知的所有 master，slave 发送 INFO 命令
* 当 master 被 sentinel 标记为客观下线时，sentinel 向下线的 master 的所有 slave 发送 INFO 命令的频率会从 10 秒一次改为 1 秒一次
* 若没有足够数量的 sentinel 同意 master 已经下线，master 的客观下线状态就会被移除； 若 master 重新向 sentinel 的 PING 命令返回有效回复，master 的主观下线状态就会被移除当使用 sentinel 模式的时候，客户端就不要直接连接 Redis，而是连接 sentinel 的 ip 和 port，由 sentinel 来提供具体的可提供服务的 Redis 实现，这样当 master 节点挂掉以后，sentinel 就会感知并将新的 master 节点提供给使用者。
Sentinel 模式搭建
环境准备：
master 节点 192.168.30.128 sentinel 端口：26379
slave 节点 192.168.30.129 sentinel 端口：26379
slave 节点 192.168.30.130 sentinel 端口：26379修改配置：
前面已经下载安装了 redis，这里省略，直接修改 sentinel 配置文件。
192.168.30.128
# vim /usr/local/redis/sentinel.confdaemonize yeslogfile /usr/local/redis/sentinel.log dir /usr/local/redis/sentinel #sentinel 工作目录 sentinel monitor mymaster 192.168.30.128 6379 2 # 判断 master 失效至少需要 2 个 sentinel 同意，建议设置为 n /2+1，n 为 sentinel 个数 sentinel auth-pass mymaster 123456
sentinel down-after-milliseconds mymaster 30000 # 判断 master 主观下线时间，默认 30s这里需要注意，sentinel auth-pass mymaster 123456 需要配置在 sentinel monitor mymaster 192.168.30.128 6379 2 下面，否则启动报错：
# /usr/local/bin/redis-sentinel /usr/local/redis/sentinel.conf*** FATAL CONFIG FILE ERROR ***
Reading the configuration file, at line 104 sentinel auth-pass mymaster 123456 No such master with specified name.全部启动 sentinel：
# mkdir /usr/local/redis/sentinel chown -R redis:redis /usr/local/redis# /usr/local/bin/redis-sentinel /usr/local/redis/sentinel.conf任一主机查看日志：
# tail -f /usr/local/redis/sentinel.log21574:X 09 May 2019 15:32:04.298 # Sentinel ID is 30c417116a8edbab09708037366c4a7471beb77021574:X 09 May 2019 15:32:04.298 # +monitor master mymaster 192.168.30.128 6379 quorum 221574:X 09 May 2019 15:32:04.299 * +slave slave 192.168.30.129:6379 192.168.30.129 6379 @ mymaster 192.168.30.128 6379
21574:X 09 May 2019 15:32:04.300 * +slave slave 192.168.30.130:6379 192.168.30.130 6379 @ mymaster 192.168.30.128 6379
21574:X 09 May 2019 15:32:16.347 * +sentinel sentinel 79b8d61626afd4d059fb5a6a63393e9a1374e78f 192.168.30.129 26379 @ mymaster 192.168.30.128 6379
21574:X 09 May 2019 15:32:31.584 * +sentinel sentinel d7b429dcba792103ef0d80827dd0910bd9284d21 192.168.30.130 26379 @ mymaster 192.168.30.128 6379Sentinel 模式下的几个事件：
· +reset-master ：主服务器已被重置。· +slave ：一个新的从服务器已经被 Sentinel 识别并关联。· +failover-state-reconf-slaves ：故障转移状态切换到了 reconf-slaves 状态。· +failover-detected ：另一个 Sentinel 开始了一次故障转移操作，或者一个从服务器转换成了主服务器。· +slave-reconf-sent ：领头（leader）的 Sentinel 向实例发送了 [SLAVEOF](/commands/slaveof.html) 命令，为实例设置新的主服务器。· +slave-reconf-inprog ：实例正在将自己设置为指定主服务器的从服务器，但相应的同步过程仍未完成。· +slave-reconf-done ：从服务器已经成功完成对新主服务器的同步。· -dup-sentinel ：对给定主服务器进行监视的一个或多个 Sentinel 已经因为重复出现而被移除 —— 当 Sentinel 实例重启的时候，就会出现这种情况。· +sentinel ：一个监视给定主服务器的新 Sentinel 已经被识别并添加。· +sdown ：给定的实例现在处于主观下线状态。· -sdown ：给定的实例已经不再处于主观下线状态。· +odown ：给定的实例现在处于客观下线状态。· -odown ：给定的实例已经不再处于客观下线状态。· +new-epoch ：当前的纪元（epoch）已经被更新。· +try-failover ：一个新的故障迁移操作正在执行中，等待被大多数 Sentinel 选中（waiting to be elected by the majority）。· +elected-leader ：赢得指定纪元的选举，可以进行故障迁移操作了。· +failover-state-select-slave ：故障转移操作现在处于 select-slave 状态 —— Sentinel 正在寻找可以升级为主服务器的从服务器。· no-good-slave ：Sentinel 操作未能找到适合进行升级的从服务器。Sentinel 会在一段时间之后再次尝试寻找合适的从服务器来进行升级，又或者直接放弃执行故障转移操作。· selected-slave ：Sentinel 顺利找到适合进行升级的从服务器。· failover-state-send-slaveof-noone ：Sentinel 正在将指定的从服务器升级为主服务器，等待升级功能完成。· failover-end-for-timeout ：故障转移因为超时而中止，不过最终所有从服务器都会开始复制新的主服务器（slaves will eventually be configured to replicate with the new master anyway）。· failover-end ：故障转移操作顺利完成。所有从服务器都开始复制新的主服务器了。· +switch-master ：配置变更，主服务器的 IP 和地址已经改变。 这是绝大多数外部用户都关心的信息。· +tilt ：进入 tilt 模式。· -tilt ：退出 tilt 模式。master 宕机演示：
192.168.30.128
# systemctl stop redis# tail -f /usr/local/redis/sentinel.log22428:X 09 May 2019 15:51:29.287 # +sdown master mymaster 192.168.30.128 637922428:X 09 May 2019 15:51:29.371 # +odown master mymaster 192.168.30.128 6379 #quorum 2/222428:X 09 May 2019 15:51:29.371 # +new-epoch 122428:X 09 May 2019 15:51:29.371 # +try-failover master mymaster 192.168.30.128 637922428:X 09 May 2019 15:51:29.385 # +vote-for-leader 30c417116a8edbab09708037366c4a7471beb770 122428:X 09 May 2019 15:51:29.403 # d7b429dcba792103ef0d80827dd0910bd9284d21 voted for 30c417116a8edbab09708037366c4a7471beb770 122428:X 09 May 2019 15:51:29.408 # 79b8d61626afd4d059fb5a6a63393e9a1374e78f voted for 30c417116a8edbab09708037366c4a7471beb770 122428:X 09 May 2019 15:51:29.451 # +elected-leader master mymaster 192.168.30.128 637922428:X 09 May 2019 15:51:29.451 # +failover-state-select-slave master mymaster 192.168.30.128 637922428:X 09 May 2019 15:51:29.528 # +selected-slave slave 192.168.30.129:6379 192.168.30.129 6379 @ mymaster 192.168.30.128 637922428:X 09 May 2019 15:51:29.528 * +failover-state-send-slaveof-noone slave 192.168.30.129:6379 192.168.30.129 6379 @ mymaster 192.168.30.128 6379
22428:X 09 May 2019 15:51:29.594 * +failover-state-wait-promotion slave 192.168.30.129:6379 192.168.30.129 6379 @ mymaster 192.168.30.128 6379
22428:X 09 May 2019 15:51:30.190 # +promoted-slave slave 192.168.30.129:6379 192.168.30.129 6379 @ mymaster 192.168.30.128 637922428:X 09 May 2019 15:51:30.190 # +failover-state-reconf-slaves master mymaster 192.168.30.128 637922428:X 09 May 2019 15:51:30.258 * +slave-reconf-sent slave 192.168.30.130:6379 192.168.30.130 6379 @ mymaster 192.168.30.128 6379
22428:X 09 May 2019 15:51:30.511 # -odown master mymaster 192.168.30.128 637922428:X 09 May 2019 15:51:31.233 * +slave-reconf-inprog slave 192.168.30.130:6379 192.168.30.130 6379 @ mymaster 192.168.30.128 6379
22428:X 09 May 2019 15:51:31.233 * +slave-reconf-done slave 192.168.30.130:6379 192.168.30.130 6379 @ mymaster 192.168.30.128 6379
22428:X 09 May 2019 15:51:31.297 # +failover-end master mymaster 192.168.30.128 637922428:X 09 May 2019 15:51:31.297 # +switch-master mymaster 192.168.30.128 6379 192.168.30.129 637922428:X 09 May 2019 15:51:31.298 * +slave slave 192.168.30.130:6379 192.168.30.130 6379 @ mymaster 192.168.30.129 6379
22428:X 09 May 2019 15:51:31.298 * +slave slave 192.168.30.128:6379 192.168.30.128 6379 @ mymaster 192.168.30.129 6379
22428:X 09 May 2019 15:52:31.307 # +sdown slave 192.168.30.128:6379 192.168.30.128 6379 @ mymaster 192.168.30.129 6379从日志中可以看到，master 已经从 192.168.30.128 转移到 192.168.30.129 上
192.168.30.129 上查看集群信息
# /usr/local/bin/redis-cli -h 192.168.30.129 -p 6379 -a 123456Warning: Using a password with -a or -u option on the command line interface may not be safe.
192.168.30.129:6379 info replication# Replicationrole:master
connected_slaves:1
slave0:ip=192.168.30.130,port=6379,state=online,offset=291039,lag=1
master_replid:757aff269236ed2707ba584a86a40716c1c76d74
master_replid2:47a862fc0ff20362be29096ecdcca6d432070ee9
master_repl_offset:291182
second_repl_offset:248123
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:291182
192.168.30.129:6379 set key4 linux
OK当前集群中只有一个 slave——192.168.30.130，master 是 192.168.30.129，且 192.168.30.129 具有写权限。
192.168.30.130 上查看 redis 的配置文件也可以看到 replicaof 192.168.30.129 6379，这是 sentinel 在选举 master 是做的修改。
重新把 192.168.30.128 上进程启动
# systemctl start redis# tail -f /usr/local/redis/sentinel.log22428:X 09 May 2019 15:51:31.297 # +switch-master mymaster 192.168.30.128 6379 192.168.30.129 637922428:X 09 May 2019 15:51:31.298 * +slave slave 192.168.30.130:6379 192.168.30.130 6379 @ mymaster 192.168.30.129 6379
22428:X 09 May 2019 15:51:31.298 * +slave slave 192.168.30.128:6379 192.168.30.128 6379 @ mymaster 192.168.30.129 6379
22428:X 09 May 2019 15:52:31.307 # +sdown slave 192.168.30.128:6379 192.168.30.128 6379 @ mymaster 192.168.30.129 637922428:X 09 May 2019 16:01:24.872 # -sdown slave 192.168.30.128:6379 192.168.30.128 6379 @ mymaster 192.168.30.129 6379查看集群信息
# /usr/local/bin/redis-cli -h 192.168.30.128 -p 6379 -a 123456Warning: Using a password with -a or -u option on the command line interface may not be safe.
192.168.30.128:6379 info replication# Replicationrole:slave
master_host:192.168.30.129
master_port:6379
master_link_status:up
master_last_io_seconds_ago:0
master_sync_in_progress:0
slave_repl_offset:514774
slave_priority:100
slave_read_only:1
connected_slaves:0
master_replid:757aff269236ed2707ba584a86a40716c1c76d74
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:514774
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:376528
repl_backlog_histlen:138247
192.168.30.128:6379 get key4 linux 192.168.30.128:6379 set key5(error) ERR wrong number of arguments for set command即使 192.168.30.128 重新启动 redis 服务，也是作为 slave 加入 redis 集群，192.168.30.129 仍然是 master。
Cluster 模式 Cluster 模式介绍
sentinel 模式基本可以满足一般生产的需求，具备高可用性。但是当数据量过大到一台服务器存放不下的情况时，主从模式或 sentinel 模式就不能满足需求了，这个时候需要对存储的数据进行分片，将数据存储到多个 Redis 实例中。cluster 模式的出现就是为了解决单机 Redis 容量有限的问题，将 Redis 的数据根据一定的规则分配到多台机器。
cluster 可以说是 sentinel 和主从模式的结合体，通过 cluster 可以实现主从和 master 重选功能，所以如果配置两个副本三个分片的话，就需要六个 Redis 实例。因为 Redis 的数据是根据一定规则分配到 cluster 的不同机器的，当数据量过大时，可以新增机器进行扩容。
使用集群，只需要将 redis 配置文件中的 cluster-enable 配置打开即可。每个集群中至少需要三个主数据库才能正常运行，新增节点非常方便。
cluster 集群特点：
* 多个 redis 节点网络互联，数据共享
* 所有的节点都是一主一从（也可以是一主多从），其中从不提供服务，仅作为备用
* 不支持同时处理多个 key（如 MSET/MGET），因为 redis 需要把 key 均匀分布在各个节点上， 并发量很高的情况下同时创建 key-value 会降低性能并导致不可预测的行为
* 支持在线增加、删除节点
* 客户端可以连接任何一个主节点进行读写Cluster 模式搭建
环境准备：
三台机器，分别开启两个 redis 服务（端口）192.168.30.128 端口：7001,7002
192.168.30.129 端口：7003,7004
192.168.30.130 端口：7005,7006修改配置文件：
192.168.30.128
# mkdir /usr/local/redis/cluster# cp /usr/local/redis/redis.conf /usr/local/redis/cluster/redis_7001.conf# cp /usr/local/redis/redis.conf /usr/local/redis/cluster/redis_7002.conf# chown -R redis:redis /usr/local/redis# mkdir -p /data/redis/cluster/{redis_7001,redis_7002} chown -R redis:redis /data/redis# vim /usr/local/redis/cluster/redis_7001.confbind 192.168.30.128
port 7001
daemonize yespidfile /var/run/redis_7001.pid logfile /usr/local/redis/cluster/redis_7001.log dir /data/redis/cluster/redis_7001 #replicaof 192.168.30.129 6379masterauth 123456
requirepass 123456
appendonly yescluster-enabled yescluster-config-file nodes_7001.conf
cluster-node-timeout 15000# vim /usr/local/redis/cluster/redis_7002.confbind 192.168.30.128
port 7002
daemonize yespidfile /var/run/redis_7002.pid logfile /usr/local/redis/cluster/redis_7002.log dir /data/redis/cluster/redis_7002 #replicaof 192.168.30.129 6379masterauth 123456 requirepass 123456 appendonly yescluster-enabled yescluster-config-file nodes_7002.conf
cluster-node-timeout 15000其它两台机器配置与 192.168.30.128 一致，此处省略
启动 redis 服务：
# redis-server /usr/local/redis/cluster/redis_7001.conf# tail -f /usr/local/redis/cluster/redis_7001.log# redis-server /usr/local/redis/cluster/redis_7002.conf# tail -f /usr/local/redis/cluster/redis_7002.log其它两台机器启动与 192.168.30.128 一致，此处省略
安装 ruby 并创建集群（低版本）：
如果 redis 版本比较低，则需要安装 ruby。任选一台机器安装 ruby 即可
# yum -y groupinstall Development Tools # yum install -y gdbm-devel libdb4-devel libffi-devel libyaml libyaml-devel ncurses-devel openssl-devel readline-devel tcl-devel# mkdir -p ~/rpmbuild/{BUILD,BUILDROOT,RPMS,SOURCES,SPECS,SRPMS}# wget http://cache.ruby-lang.org/pub/ruby/2.2/ruby-2.2.3.tar.gz -P ~/rpmbuild/SOURCES# wget http://raw.githubusercontent.com/tjinjin/automate-ruby-rpm/master/ruby22x.spec -P ~/rpmbuild/SPECS# rpmbuild -bb ~/rpmbuild/SPECS/ruby22x.spec# rpm -ivh ~/rpmbuild/RPMS/x86_64/ruby-2.2.3-1.el7.x86_64.rpm# gem install redis # 目的是安装这个，用于配置集群# cp /usr/local/redis/src/redis-trib.rb /usr/bin/# redis-trib.rb create --replicas 1 192.168.30.128:7001 192.168.30.128:7002 192.168.30.129:7003 192.168.30.129:7004 192.168.30.130:7005 192.168.30.130:7006创建集群：
我这里是 redis5.0.4，所以不需要安装 ruby，直接创建集群即可
# redis-cli -a 123456 --cluster create 192.168.30.128:7001 192.168.30.128:7002 192.168.30.129:7003 192.168.30.129:7004 192.168.30.130:7005 192.168.30.130:7006 --cluster-replicas 1Warning: Using a password with -a or -u option on the command line interface may not be safe. Performing hash slots allocation on 6 nodes...
Master[0] - Slots 0 - 5460
Master[1] - Slots 5461 - 10922
Master[2] - Slots 10923 - 16383
Adding replica 192.168.30.129:7004 to 192.168.30.128:7001
Adding replica 192.168.30.130:7006 to 192.168.30.129:7003
Adding replica 192.168.30.128:7002 to 192.168.30.130:7005
M: 80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001
slots:[0-5460] (5461 slots) master
S: b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002
replicates 6788453ee9a8d7f72b1d45a9093838efd0e501f1
M: 4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003
slots:[5461-10922] (5462 slots) master
S: b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004
replicates 80c80a3f3e33872c047a8328ad579b9bea001ad8
M: 6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005
slots:[10923-16383] (5461 slots) master
S: 277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006
replicates 4d74ec66e898bf09006dac86d4928f9fad81f373
Can I set the above configuration? (type yes to accept): yes # 输入 yes，接受上面配置 Nodes configuration updated Assign a different config epoch to each node Sending CLUSTER MEET messages to join the cluster可以看到，
192.168.30.128:7001 是 master，它的 slave 是 192.168.30.129:7004；192.168.30.129:7003 是 master，它的 slave 是 192.168.30.130:7006；192.168.30.130:7005 是 master，它的 slave 是 192.168.30.128:7002自动生成 nodes.conf 文件：
# ls /data/redis/cluster/redis_7001/appendonly.aof dump.rdb nodes-7001.conf# vim /data/redis/cluster/redis_7001/nodes-7001.conf 6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557454406312 5 connected 10923-16383
277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557454407000 6 connected
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557454408371 5 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 myself,master - 0 1557454406000 1 connected 0-5460
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557454407366 4 connected
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557454407000 3 connected 5461-10922
vars currentEpoch 6 lastVoteEpoch 0集群操作
登录集群：
# redis-cli -c -h 192.168.30.128 -p 7001 -a 123456 # -c，使用集群方式登录查看集群信息：
192.168.30.128:7001 CLUSTER INFO # 集群状态 cluster_state:ok
cluster_slots_assigned:16384
cluster_slots_ok:16384
cluster_slots_pfail:0
cluster_slots_fail:0
cluster_known_nodes:6
cluster_size:3
cluster_current_epoch:6
cluster_my_epoch:1
cluster_stats_messages_ping_sent:580
cluster_stats_messages_pong_sent:551
cluster_stats_messages_sent:1131
cluster_stats_messages_ping_received:546
cluster_stats_messages_pong_received:580
cluster_stats_messages_meet_received:5
cluster_stats_messages_received:1131列出节点信息：
192.168.30.128:7001 CLUSTER NODES # 列出节点信息 6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557455176000 5 connected 10923-16383
277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557455174000 6 connected
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557455175000 5 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 myself,master - 0 1557455175000 1 connected 0-5460
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557455174989 4 connected
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557455175995 3 connected 5461-10922这里与 nodes.conf 文件内容相同
写入数据：
192.168.30.128:7001 set key111 aaa
- Redirected to slot [13680] located at 192.168.30.130:7005 # 说明数据到了 192.168.30.130:7005 上 OK
192.168.30.130:7005 set key222 bbb
- Redirected to slot [2320] located at 192.168.30.128:7001 # 说明数据到了 192.168.30.128:7001 上 OK
192.168.30.128:7001 set key333 ccc
- Redirected to slot [7472] located at 192.168.30.129:7003 # 说明数据到了 192.168.30.129:7003 上 OK
192.168.30.129:7003 get key111
- Redirected to slot [13680] located at 192.168.30.130:7005 aaa 192.168.30.130:7005 get key333
- Redirected to slot [7472] located at 192.168.30.129:7003 ccc 192.168.30.129:7003可以看出 redis cluster 集群是去中心化的，每个节点都是平等的，连接哪个节点都可以获取和设置数据。
当然，平等指的是 master 节点，因为 slave 节点根本不提供服务，只是作为对应 master 节点的一个备份。
增加节点：
192.168.30.129 上增加一节点：
# cp /usr/local/redis/cluster/redis_7003.conf /usr/local/redis/cluster/redis_7007.conf# vim /usr/local/redis/cluster/redis_7007.confbind 192.168.30.129
port 7007
daemonize yespidfile /var/run/redis_7007.pid logfile /usr/local/redis/cluster/redis_7007.log dir /data/redis/cluster/redis_7007 #replicaof 192.168.30.129 6379masterauth 123456 requirepass 123456 appendonly yescluster-enabled yescluster-config-file nodes_7007.conf
cluster-node-timeout 15000# mkdir /data/redis/cluster/redis_7007# chown -R redis:redis /usr/local/redis chown -R redis:redis /data/redis# redis-server /usr/local/redis/cluster/redis_7007.conf192.168.30.130 上增加一节点：
# cp /usr/local/redis/cluster/redis_7005.conf /usr/local/redis/cluster/redis_7008.conf# vim /usr/local/redis/cluster/redis_7007.confbind 192.168.30.130
port 7008
daemonize yespidfile /var/run/redis_7008.pid logfile /usr/local/redis/cluster/redis_7008.log dir /data/redis/cluster/redis_7008 #replicaof 192.168.30.130 6379masterauth 123456 requirepass 123456 appendonly yescluster-enabled yescluster-config-file nodes_7008.conf
cluster-node-timeout 15000# mkdir /data/redis/cluster/redis_7008# chown -R redis:redis /usr/local/redis chown -R redis:redis /data/redis# redis-server /usr/local/redis/cluster/redis_7008.conf集群中增加节点：
192.168.30.129:7003 CLUSTER MEET 192.168.30.129 7007
192.168.30.129:7003 CLUSTER NODES
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 myself,master - 0 1557457361000 3 connected 5461-10922
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557457364746 1 connected 0-5460
277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557457362000 6 connected
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557457363000 4 connected
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557457362000 5 connected
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557457362729 0 connected
6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557457363739 5 connected 10923-16383192.168.30.129:7003 CLUSTER MEET 192.168.30.130 7008
192.168.30.129:7003 CLUSTER NODES
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 myself,master - 0 1557457489000 3 connected 5461-10922
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557457489000 1 connected 0-5460
277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557457489000 6 connected
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557457488000 4 connected
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557457489472 5 connected
1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 master - 0 1557457489259 0 connected
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557457489000 0 connected
6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557457490475 5 connected 10923-16383可以看到，新增的节点都是以 master 身份加入集群的
更换节点身份：
将新增的 192.168.30.130:7008 节点身份改为 192.168.30.129:7007 的 slave
# redis-cli -c -h 192.168.30.130 -p 7008 -a 123456 cluster replicate e51ab166bc0f33026887bcf8eba0dff3d5b0bf14cluster replicate 后面跟 node_id，更改对应节点身份。也可以登入集群更改
# redis-cli -c -h 192.168.30.130 -p 7008 -a 123456192.168.30.130:7008 CLUSTER REPLICATE e51ab166bc0f33026887bcf8eba0dff3d5b0bf14
192.168.30.130:7008 CLUSTER NODES
277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557458316881 3 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557458314864 1 connected 0-5460
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557458316000 3 connected 5461-10922
6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557458315872 5 connected 10923-16383
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557458317890 5 connected
1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 myself,slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557458315000 7 connected
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557458315000 1 connected
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557458314000 0 connected查看相应的 nodes.conf 文件，可以发现有更改，它记录当前集群的节点信息
# cat /data/redis/cluster/redis_7001/nodes-7001.conf1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557458236169 7 connected
6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557458235000 5 connected 10923-16383
277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557458234103 6 connected
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557458235129 5 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 myself,master - 0 1557458234000 1 connected 0-5460
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557458236000 4 connected
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557458236000 0 connected
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557458233089 3 connected 5461-10922
vars currentEpoch 7 lastVoteEpoch 0删除节点：
192.168.30.130:7008 CLUSTER FORGET 1a1c7f02fce87530bd5abdfc98df1cffce4f1767(error) ERR I tried hard but I can t forget myself... # 无法删除登录节点
192.168.30.130:7008 CLUSTER FORGET e51ab166bc0f33026887bcf8eba0dff3d5b0bf14
(error) ERR Can t forget my master! # 不能删除自己的 master 节点 192.168.30.130:7008 CLUSTER FORGET 6788453ee9a8d7f72b1d45a9093838efd0e501f1
OK # 可以删除其它的 master 节点 192.168.30.130:7008 CLUSTER NODES
277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557458887328 3 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557458887000 1 connected 0-5460
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557458886000 3 connected 5461-10922
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave - 0 1557458888351 5 connected
1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 myself,slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557458885000 7 connected
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557458883289 1 connected
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557458885310 0 connected
192.168.30.130:7008 CLUSTER FORGET b4d3eb411a7355d4767c6c23b4df69fa183ef8bc
OK # 可以删除其它的 slave 节点 192.168.30.130:7008 CLUSTER NODES
277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557459031397 3 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557459032407 1 connected 0-5460
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557459035434 3 connected 5461-10922
6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557459034000 5 connected 10923-16383
1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 myself,slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557459032000 7 connected
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557459034000 1 connected
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557459034427 0 connected保存配置：
192.168.30.130:7008 CLUSTER SAVECONFIG # 将节点配置信息保存到硬盘 OK
# cat /data/redis/cluster/redis_7001/nodes-7001.conf1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557458236169 7 connected
6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557458235000 5 connected 10923-16383
277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557458234103 6 connected
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557458235129 5 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 myself,master - 0 1557458234000 1 connected 0-5460
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557458236000 4 connected
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557458236000 0 connected
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557458233089 3 connected 5461-10922
vars currentEpoch 7 lastVoteEpoch 0# redis-cli -c -h 192.168.30.130 -p 7008 -a 123456Warning: Using a password with -a or -u option on the command line interface may not be safe.
192.168.30.130:7008 CLUSTER NODES
277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557459500741 3 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557459500000 1 connected 0-5460
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557459501000 3 connected 5461-10922
6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557459500000 5 connected 10923-16383
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557459499737 5 connected
1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 myself,slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557459499000 7 connected
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557459501750 1 connected
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557459498000 0 connected
可以看到，之前删除的节点又恢复了，这是因为对应的配置文件没有删除，执行 CLUSTER SAVECONFIG 恢复。
模拟 master 节点挂掉：
192.168.30.128
# netstat -lntp |grep 7001tcp 0 0 192.168.30.128:17001 0.0.0.0:* LISTEN 6701/redis-server 1
tcp 0 0 192.168.30.128:7001 0.0.0.0:* LISTEN 6701/redis-server 1
# kill 6701192.168.30.130:7008 CLUSTER NODES
277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557461178000 3 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master,fail - 1557460950483 1557460947145 1 disconnected
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557461174922 3 connected 5461-10922
6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557461181003 5 connected 10923-16383
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557461179993 5 connected
1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 myself,slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557461176000 7 connected
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 master - 0 1557461178981 8 connected 0-5460
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557461179000 0 connected对应 7001 的一行可以看到，master fail，状态为 disconnected；而对应 7004 的一行，slave 已经变成 master。
重新启动 7001 节点：
# redis-server /usr/local/redis/cluster/redis_7001.conf192.168.30.130:7008 CLUSTER NODES
277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557461307000 3 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 slave b6331cbc986794237c83ed2d5c30777c1551546e 0 1557461305441 8 connected
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557461307962 3 connected 5461-10922
6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557461304935 5 connected 10923-16383
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557461306000 5 connected
1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 myself,slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557461305000 7 connected
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 master - 0 1557461308972 8 connected 0-5460
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557461307000 0 connected可以看到，7001 节点启动后为 slave 节点，并且是 7004 的 slave 节点。即 master 节点如果挂掉，它的 slave 节点变为新 master 节点继续对外提供服务，而原来的 master 节点如果重启，则变为新 master 节点的 slave 节点。
另外，如果这里是拿 7007 节点做测试的话，会发现 7008 节点并不会切换，这是因为 7007 节点上根本没数据。集群数据被分为三份，采用哈希槽 (hash slot)的方式来分配 16384 个 slot 的话，它们三个节点分别承担的 slot 区间是：
节点 7004 覆盖 0-5460
节点 7003 覆盖 5461-10922
节点 7005 覆盖 10923-16383以上是“Redis 集群的示例分析”这篇文章的所有内容，感谢各位的阅读！希望分享的内容对大家有帮助，更多相关知识，欢迎关注丸趣 TV 行业资讯频道！
向 AI 问一下细节
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