1、为什么要用redis-cluster
a、并发要求
redis官方声称可以达到10万每秒，但是如果业务需要每秒100万条呢？
b、数据量太大
一台服务器的内存正常是16-256G，如果业务需要500G内存怎么办？
2、搭建redis-cluster
针对上述问题，redis-cluster集群就提供了很好的解决方案。
（1）、先准备环境，开启多个redis实例
[root@localhost redis_conf]# ls
redis-.conf redis-.conf redis-.conf
redis-.conf redis-.conf redis-.conf
[root@localhost redis_conf]#
暂时准备了6个配置文件，
daemonize yes
port
logfile ./data//redis.log #日志存放位置
dir ./data/ # 数据存放位置
dbfilename dbmp.rdb # 数据文件名称
cluster-enabled yes # 开启集群模式
cluster-config-file nodes-.conf # 集群内部的配置文件
cluster-require-full-coverage no # redis cluster需要16384个slot都正常的时候才能对外提供服务，换句话说，只要任何一个slot异常那么整个cluster不对外提供服务。 因此生产环境一般为no
上面的配置为redis-7000.conf的配置文件内容，其他配置文件内容相同，只是将7000全部改成对应的端口。
可以使用如下命令快速生成：
sed "s/7000/7001/g" redis-.conf > redis-.conf
通过sed命令将redis-7000.conf中的7000修改成7001，然后写入redis-7001.conf文件中
每个节点仅仅是端口的不同。
注意：还要确保配置中的日志以及数据存放文件夹存在。
比如我的：
[root@localhost redis_conf]# mkdir -p data/{,,,,,}
[root@localhost redis_conf]# tree
.
├── data
│ ├──
│ ├──
│ ├──
│ ├──
│ ├──
│ └──
├── redis-.conf
├── redis-.conf
├── redis-.conf
├── redis-.conf
├── redis-.conf
└── redis-.conf
directories, files
(2)、运行redis实例
[root@localhost redis_conf]# redis-server redis-.conf
[root@localhost redis_conf]# redis-server redis-.conf
[root@localhost redis_conf]# redis-server redis-.conf
[root@localhost redis_conf]# redis-server redis-.conf
[root@localhost redis_conf]# redis-server redis-.conf
[root@localhost redis_conf]# redis-server redis-.conf
查看是否已经启动
[root@localhost redis_conf]# ps -ef | grep redis
root : ? :: redis-server *: [cluster]
root : ? :: redis-server *: [cluster]
root : ? :: redis-server *: [cluster]
root : ? :: redis-server *: [cluster]
root : ? :: redis-server *: [cluster]
root : ? :: redis-server *: [cluster]
root : pts/ :: grep --color=auto redis
[root@localhost redis_conf]#
此时集群还用不了，可以登录redis查看
[root@localhost redis_conf]# redis-cli -p
127.0.0.1:> set name felixi
(error) CLUSTERDOWN Hash slot not served
127.0.0.1:>
(3)、创建redis-cluster
a、准备ruby环境
下载，编译，安装ruby （ruby官网地址）
、下载（个人用的当前的最新版本2.6.0）
wget https://cache.ruby-lang.org/pub/ruby/2.6/ruby-2.6.0.tar.gz
、解压，安装
tar -zxvf ruby-2.6..tar.gz
cd ruby-2.6.
./configure --prefix=/opt/ruby/
make && make install
、添加环境变量
export PATH=/opt/ruby/bin/:$PATH # 将这句添加到./bashrc和/etc/profile文件末尾。
source ./bashrc /etc/profile # 加载一下
b、查看是否已经安装
[root@localhost ~]# gem -v
3.0.
[root@localhost ~]#
c、下载安装ruby操作redis的模块包
[root@localhost ~]# gem install redis
Successfully installed redis-4.1.
Parsing documentation for redis-4.1.
Done installing documentation for redis after seconds
gem installed
[root@localhost ~]#
7、启动集群
我的redis版本是5.0.2，使用如下方式启动
redis-cli --cluster create 127.0.0.1: 127.0.0.1: 127.0.0.1: 127.0.0.1: 127.0.0.1: 127.0.0.1: --cluster-replicas
其他旧版本可能需要如下命令：注意(redis-trib.rb可能找不到，可以通过find / -name redis-trib.rb来查找)
/opt/redis-4.0./src/redis-trib.rb create --replicas 127.0.0.1: 127.0.0.1: 127.0.0.1: 127.0.0.1: 127.0.0.1: 127.0.0.1:
8、出现如下说明启动成功
[root@localhost ~]# redis-cli --cluster create 127.0.0.1: 127.0.0.1: 127.0.0.1: 127.0.0.1: 127.0.0.1: 127.0.0.1: --cluster-replicas
>>> Performing hash slots allocation on nodes...
Master[] -> Slots -
Master[] -> Slots -
Master[] -> Slots -
Adding replica 127.0.0.1: to 127.0.0.1:
Adding replica 127.0.0.1: to 127.0.0.1:
Adding replica 127.0.0.1: to 127.0.0.1:
>>> Trying to optimize slaves allocation for anti-affinity
[WARNING] Some slaves are in the same host as their master
M: 511bc46a1da42e3964ce41f48234076bd5743baf 127.0.0.1:
slots:[-] ( slots) master
M: bb029209525fb9aa2eeaa8c27182065ca1b29457 127.0.0.1:
slots:[-] ( slots) master
M: 72b6ad9d36ba9cc7770bfaf6899c8e3262c677b0 127.0.0.1:
slots:[-] ( slots) master
S: 25c00188cc8b58f5442ac674647389ab4f9206e9 127.0.0.1:
replicates 511bc46a1da42e3964ce41f48234076bd5743baf
S: bd093c559ebbc54fead2da9200d6f0c10a90bc87 127.0.0.1:
replicates bb029209525fb9aa2eeaa8c27182065ca1b29457
S: 3c0031255f960fbc15bbf9a78dacd7427ac24115 127.0.0.1:
replicates 72b6ad9d36ba9cc7770bfaf6899c8e3262c677b0
Can I set the above configuration? (type 'yes' to accept): yes
>>> Nodes configuration updated
>>> Assign a different config epoch to each node
>>> Sending CLUSTER MEET messages to join the cluster
Waiting for the cluster to join
...
>>> Performing Cluster Check (using node 127.0.0.1:)
M: 511bc46a1da42e3964ce41f48234076bd5743baf 127.0.0.1:
slots:[-] ( slots) master
additional replica(s)
M: 72b6ad9d36ba9cc7770bfaf6899c8e3262c677b0 127.0.0.1:
slots:[-] ( slots) master
additional replica(s)
M: bb029209525fb9aa2eeaa8c27182065ca1b29457 127.0.0.1:
slots:[-] ( slots) master
additional replica(s)
S: bd093c559ebbc54fead2da9200d6f0c10a90bc87 127.0.0.1:
slots: ( slots) slave
replicates bb029209525fb9aa2eeaa8c27182065ca1b29457
S: 25c00188cc8b58f5442ac674647389ab4f9206e9 127.0.0.1:
slots: ( slots) slave
replicates 511bc46a1da42e3964ce41f48234076bd5743baf
S: 3c0031255f960fbc15bbf9a78dacd7427ac24115 127.0.0.1:
slots: ( slots) slave
replicates 72b6ad9d36ba9cc7770bfaf6899c8e3262c677b0
[OK] All nodes agree about slots configuration.
>>> Check for open slots...
>>> Check slots coverage...
[OK] All slots covered.
[root@localhost ~]#
9、查看主从状态
redis-cli -p info replication
结果如下：
[root@localhost ~]# redis-cli -p info replication
# Replication
role:master
connected_slaves:
slave0:ip=127.0.0.1,port=,state=online,offset=,lag=
master_replid:2b20fa4941542dc58d9fc2c32fe6f3dbb6cce72b
master_replid2:
master_repl_offset:
second_repl_offset:-
repl_backlog_active:
repl_backlog_size:
repl_backlog_first_byte_offset:
repl_backlog_histlen:
[root@localhost ~]# redis-cli -p info replication
# Replication
role:slave
master_host:127.0.0.1
master_port:
master_link_status:up
master_last_io_seconds_ago:
master_sync_in_progress:
slave_repl_offset:
slave_priority:
slave_read_only:
connected_slaves:
master_replid:ad11aa24aa797d942a54550ee77ab0e185e9d92c
master_replid2:
master_repl_offset:
second_repl_offset:-
repl_backlog_active:
repl_backlog_size:
repl_backlog_first_byte_offset:
repl_backlog_histlen:
[root@localhost ~]#
9、向redis集群写入数据，查看数据流向
redis-cli -p 7000 -c #这里会将key自动的重定向，放到某一个节点的slot槽位中
效果如下：
[root@localhost ~]# redis-cli -p -c
127.0.0.1:> keys *
(empty list or set)
127.0.0.1:>
127.0.0.1:> set name felix
-> Redirected to slot [] located at 127.0.0.1:
OK
127.0.0.1:> keys *
) "name"
127.0.0.1:>
至此，集群就搭建好了