怎样搭建Redis群集

前言

Redis 集群是一个分布式（distributed）、容错（fault-tolerant）的 Redis 实现， 集群可以使用的功能是普通单机 Redis 所能使用的功能的一个子集（subset）。

Redis 集群中不存在中心（central）节点或者代理（proxy）节点， 集群的其中一个主要设计目标是达到线性可扩展性（linear scalability）。

Redis 集群提供了一种运行 Redis 的方式，其中数据在多个 Redis 节点间自动分区。Redis 集群还在分区期间提供一定程度的可用性，即在实际情况下能够在某些节点发生故障或无法通信时继续运行。但是，如果发生较大故障（例如，大多数主站不可用时），集群会停止运行。

实验环境

实验步骤

第一步:安装Redis

#安装编译环境
[root@localhost ~]# yum install gcc gcc-c++ make -y

#远程挂载源码包
[root@localhost ~]# mount.cifs //192.168.142.1/redis /mnt
Password for root@//192.168.142.1/redis:  

#解压源码包
[root@localhost ~]# cd /mnt
[root@localhost mnt]# tar zxvf redis-5.0.7.tar.gz -C /opt

#编译与安装
[root@localhost mnt]# cd /opt/redis-5.0.7/
[root@localhost redis-5.0.7]# make
[root@localhost redis-5.0.7]# make PREFIX=/usr/local/redis/ install

#建立服务命令软链接到系统
[root@localhost redis-5.0.7]# ln -s /usr/redis/bin/* /usr/local/bin/

#切入utils目录
[root@localhost redis-5.0.7]# cd /opt/redis-5.0.7/utils/

#执行启动脚本
[root@localhost utils]# ./install_server.sh
#以下内容,默认回车即可
Welcome to the redis service installer
This script will help you easily set up a running redis server

Please select the redis port for this instance: [6379] 
Selecting default: 6379
Please select the redis config file name [/etc/redis/6379.conf] 
Selected default - /etc/redis/6379.conf
Please select the redis log file name [/var/log/redis_6379.log] 
Selected default - /var/log/redis_6379.log
Please select the data directory for this instance [/var/lib/redis/6379] 
Selected default - /var/lib/redis/6379
Please select the redis executable path [] /usr/local/redis/bin/redis-server
#此处需手动指定扩展目录路径/usr/local/redis/bin/redis-server

#使用进程控制启动服务
[root@localhost utils]# /etc/init.d/redis_6379 start
Starting Redis server...

#配置redis的6379.conf文件,追加监听地址
[root@localhost utils]# vim /etc/redis/6379.conf 

#注释第70行的监听127地址,已监听所有地址
#bind 127.0.0.1 

#去掉第89行注释关闭安全保护
protected-mode no

#去掉第93行注释,开启端口6379
port 6379

#去掉第137行注释,以独立进程启动
daemonize yes

#去掉第833行注释,开启群集功能
cluster-enabled yes

#去掉第841行注释,群集名称文件设置
cluster-config-file nodes-6379.conf

#去掉第847行注释,群集超时时间设置
cluster-node-timeout 15000

#去掉第700行注释,开启aof持久化
appendonly yes

#重启服务
[root@localhost utils]# /etc/init.d/redis_6379 restart
Stopping ...
Redis stopped
Starting Redis server...

第二步:主服务器安装rvm组件

#导入key文件
[root@localhost utils]# gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3

#安装rvm
[root@localhost utils]# curl -sSL https://get.rvm.io | bash -s stable

#执行环境变量
[root@localhost utils]# source /etc/profile.d/rvm.sh

#列出ruby可以安装的版本
[root@localhost utils]# rvm list known

#安装2.4.1 版本
[root@localhost utils]# rvm install 2.4.1

#使用rubyruby2.4.1 版本
[root@localhost utils]# rvm use 2.4.1
Using /usr/local/rvm/gems/ruby-2.4.1

#查看当前ruby2.4.1 版本
[root@localhost utils]# ruby -v
ruby 2.4.1p111 (2017-03-22 revision 58053) [x86_64-linux]

#再次安装Redis
[root@localhost utils]# gem install redis

第三步:创建Redis集群

#加入所有节点地址,并加6379端口号
[root@localhost utils]# redis-cli --cluster create 192.168.142.130:6379 192.168.142.145:6379 192.168.142.146:6379 192.168.142.143:6379 192.168.142.147:6379 192.168.142.148:6379 --cluster-replicas 1 

>>> Performing hash slots allocation on 6 nodes...
Master[0] -> Slots 0 - 5460
Master[1] -> Slots 5461 - 10922
Master[2] -> Slots 10923 - 16383
Adding replica 192.168.142.147:6379 to 192.168.142.130:6379
Adding replica 192.168.142.148:6379 to 192.168.142.145:6379
Adding replica 192.168.142.143:6379 to 192.168.142.146:6379
M: a27b43ec695099b36a5c79beae70cb0364f27338 192.168.142.130:6379
   slots:[0-5460] (5461 slots) master
M: a27b43ec695099b36a5c79beae70cb0364f27338 192.168.142.145:6379
   slots:[5461-10922] (5462 slots) master
M: a27b43ec695099b36a5c79beae70cb0364f27338 192.168.142.146:6379
   slots:[10923-16383] (5461 slots) master
S: b6d317c5f192bf84e8f464ffbf6481529cd0708a 192.168.142.143:6379
   replicates a27b43ec695099b36a5c79beae70cb0364f27338
S: b6d317c5f192bf84e8f464ffbf6481529cd0708a 192.168.142.147:6379
   replicates a27b43ec695099b36a5c79beae70cb0364f27338
S: b6d317c5f192bf84e8f464ffbf6481529cd0708a 192.168.142.148:6379
   replicates a27b43ec695099b36a5c79beae70cb0364f27338
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 192.168.142.130:6379)
M: a27b43ec695099b36a5c79beae70cb0364f27338 192.168.142.130:6379
   slots:[0-16383] (16384 slots) master
   1 additional replica(s)
S: b6d317c5f192bf84e8f464ffbf6481529cd0708a 192.168.142.148:6379
   slots: (0 slots) slave
   replicates a27b43ec695099b36a5c79beae70cb0364f27338
[OK] All nodes agree about slots configuration.
>>> Check for open slots...
>>> Check slots coverage...
[OK] All 16384 slots covered.

第四步:验证群集读写

#从主节点计入数据库写数据
[root@localhost ~]# redis-cli -h 192.168.142.130 -p 6379
192.168.142.130:6379> set name yangjia
OK
192.168.142.130:6379> get name
"yangjia"

#从另一节点查看数据信息
[root@localhost ~]# redis-cli -h 192.168.142.146 -p 6379
192.168.142.146:6379> keys *
1) "name"
192.168.142.146:6379> get name
"yangjia"

#在从节点无法查看数据,提示切换主节点服务器地址
[root@localhost ~]# redis-cli -h 192.168.142.143 -p 6379
192.168.142.143:6379> keys *
1) "name"
192.168.142.143:6379> get name
(error) MOVED 5798 192.168.142.146:6379