redis基于5.0版本搭建Cluster集群

Redis支持三种集群方案：主从复制模式、Sentinel（哨兵）模式、Cluster集群模式

本文是基于Centos7系统、Redis5.0.14版本，来搭建Cluster集群模式。

安装部署比较简单，根据官方推荐，部署Redis集群至少需要6个节点（3个主节点，3个从节点），我这里为了演示就不开6台服务器了，直接在一台服务器上进行部署，这和生产环境唯一的区别就是，生产环境需要6台机器进行创建集群。

1、初始化服务器

我这里使用的是CentOS7.9系统，关闭防火墙、关闭selinux（或自行开启放行）。

2、下载redis-5.0.14

cd /usr/local/src
wget https://download.redis.io/releases/redis-5.0.14.tar.gz

1 2	cd /usr/local/src wget https://download.redis.io/releases/redis-5.0.14.tar.gz

3、编译redis

如果是6台机器，6台机器都需要执行

yum install zlib zlib-devel openssl openssl-devel gcc gcc-c++ readline readline-devel
tar xf redis-5.0.14.tar.gz
cd /usr/local/src/redis-5.0.14/deps
make lua hiredis linenoise
cd /usr/local/src/redis-5.0.14/deps/jemalloc
./configure
make && make install_bin install_include install_lib
cd /usr/local/src/redis-5.0.14
make -j 8
make PREFIX=/usr/local/redis install

yum install zlib zlib-devel openssl openssl-devel gcc gcc-c++ readline readline-devel

tar xf redis-5.0.14.tar.gz

cd /usr/local/src/redis-5.0.14/deps

make lua hiredis linenoise

cd /usr/local/src/redis-5.0.14/deps/jemalloc

./configure

make && make install_bin install_include install_lib

cd /usr/local/src/redis-5.0.14

make -j 8

make PREFIX=/usr/local/redis install

4、创建cluster目录

mkdir -p /usr/local/src/redis_cluster/{7000,7001,7002,7003,7004,7005}

1	mkdir -p /usr/local/src/redis_cluster/{7000,7001,7002,7003,7004,7005}

5、修改配置

cd /usr/local/src/redis-5.0.14
cp redis.conf redis.conf.bak

1 2	cd /usr/local/src/redis-5.0.14 cp redis.conf redis.conf.bak

vi redis.conf

1	vi redis.conf

修改的内容如下（注意替换本机IP，你也可以配置相关文件的绝对路径，否则在重启时，要注意启动目录与原来一致）

port 7000
bind 本机ip
daemonize yes
pidfile /var/run/redis_7000.pid
cluster-enabled yes
cluster-config-file nodes_7000.conf
cluster-node-timeout 15000
appendonly yes
requirepass whsir
masterauth whsir

port 7000

bind 本机ip

daemonize yes

pidfile /var/run/redis_7000.pid

cluster-enabled yes

cluster-config-file nodes_7000.conf

cluster-node-timeout 15000

appendonly yes

requirepass whsir

masterauth whsir

相关参数注释：

port 7000 #修改端口
bind 本机ip #默认ip为127.0.0.1，需要改为其他节点机器可访问的ip，否则创建集群时无法访问对应的端口，无法创建集群
daemonize yes #redis后台运行
pidfile /var/run/redis_7000.pid #pidfile文件对应7000,7001,7002,7003,7004,7005
cluster-enabled yes #开启集群把注释#去掉
cluster-config-file nodes_7000.conf #集群的配置，配置文件首次启动自动生成7000,7001,7002,7003,7004,7005文件，如果是生产环境，这里建议配置绝对路径
cluster-node-timeout 15000 #请求超时默认15秒，可自行设置
appendonly yes #aof日志开启有需要就开启，它会每次写操作都记录一条日志
requirepass和masterauth：redis密码，我这里为了方便都设置成了一样的

将redis.conf拷贝到/redis_cluster目录，并修改相应端口

for ((i=0;i<=5;i++)); do cp redis.conf /usr/local/src/redis_cluster/700$i/; done
for ((i=0;i<=5;i++)); do sed -i s#7000#700$i#g /usr/local/src/redis_cluster/700$i/redis.conf; done

1 2	for ((i=0;i<=5;i++)); do cp redis.conf /usr/local/src/redis_cluster/700$i/; done for ((i=0;i<=5;i++)); do sed -i s#7000#700$i#g /usr/local/src/redis_cluster/700$i/redis.conf; done

6、创建软连接

ln -sv /usr/local/redis/bin/redis-cli /usr/local/bin/redis-cli
ln -sv /usr/local/redis/bin/redis-server /usr/local/bin/redis-server

1 2	ln -sv /usr/local/redis/bin/redis-cli /usr/local/bin/redis-cli ln -sv /usr/local/redis/bin/redis-server /usr/local/bin/redis-server

7、将6个redis服务启动

注意：pkill redis-server停止后，启动时也还要在这个目录下执行

cd /usr/local/src/redis_cluster
for((i=0;i<=5;i++)); do redis-server /usr/local/src/redis_cluster/700$i/redis.conf; done

1 2	cd /usr/local/src/redis_cluster for((i=0;i<=5;i++)); do redis-server /usr/local/src/redis_cluster/700$i/redis.conf; done

附停止命令：

for((i=0;i<=5;i++)); do redis-cli -h IP -p 700$i -a 密码 shutdown; done

1	for((i=0;i<=5;i++)); do redis-cli -h IP -p 700$i -a 密码 shutdown; done

或

pkill redis-server

1	pkill redis-server

8、查看服务启动状态

netstat -lntp | grep redis

1	netstat -lntp \| grep redis

9、下载ruby

注意：默认yum安装的ruby版本过低，无法提供redis支持，所以这里需要通过编译安装

cd /usr/local/src/
wget https://cache.ruby-lang.org/pub/ruby/ruby-2.6.8.tar.gz

1 2	cd /usr/local/src/ wget https://cache.ruby-lang.org/pub/ruby/ruby-2.6.8.tar.gz

注：如果官方包由于某种原因无法下载，可尝试我这里的本地包（与官方包一样）：

wget https://down.whsir.com/downloads/ruby-2.6.8.tar.gz

1	wget https://down.whsir.com/downloads/ruby-2.6.8.tar.gz

10、编译安装ruby

tar xf ruby-2.6.8.tar.gz
cd ruby-2.6.8
./configure --prefix=/usr/local/ruby
make -j 8
make install

tar xf ruby-2.6.8.tar.gz

cd ruby-2.6.8

./configure --prefix=/usr/local/ruby

make -j 8

make install

查看安装后的版本

/usr/local/ruby/bin/ruby -v

1	/usr/local/ruby/bin/ruby -v

ruby 2.6.8p205 (2021-07-07 revision 67951) [x86_64-linux]

11、设置ruby环境变量

vi /etc/profile

1	vi /etc/profile

最下面添加

export PATH=$PATH:/usr/local/ruby/bin:

1	export PATH=$PATH:/usr/local/ruby/bin:

保存退出使其生效

source /etc/profile

1	source /etc/profile

12、ruby镜像加速（非必须）

为了快速的安装包，我这里替换国内的镜像

gem sources --add https://gems.ruby-china.com/ --remove https://rubygems.org/
gem sources -l

1 2	gem sources --add https://gems.ruby-china.com/ --remove https://rubygems.org/ gem sources -l

13、安装redis

gem install redis

1	gem install redis

Fetching redis-4.5.1.gem
Successfully installed redis-4.5.1
Parsing documentation for redis-4.5.1
Installing ri documentation for redis-4.5.1
Done installing documentation for redis after 0 seconds
1 gem installed

14、初始化redis集群

--cluster-replicas 1表示为集群中的每个主节点创建一个从节点，即1主1从，6个节点就是3主3从。注意替换IP地址

/usr/local/redis/bin/redis-cli --cluster create IP:7000 IP:7001 IP:7002 IP:7003 IP:7004 IP:7005 --cluster-replicas 1 -a whsir

1	/usr/local/redis/bin/redis-cli --cluster create IP:7000 IP:7001 IP:7002 IP:7003 IP:7004 IP:7005 --cluster-replicas 1 -a whsir

>>> Performing hash slots allocation on 6 nodes...
Master[0] -> Slots 0 - 5460
Master[1] -> Slots 5461 - 10922
Master[2] -> Slots 10923 - 16383
Adding replica IP:7004 to IP:7000
Adding replica IP:7005 to IP:7001
Adding replica IP:7003 to IP:7002
>>> Trying to optimize slaves allocation for anti-affinity
[WARNING] Some slaves are in the same host as their master
M: 999e387f1455993e036e50333b79627b87dcc5fd IP:7000
slots:[0-5460] (5461 slots) master
M: 77089374a717e0fe798e1f312b0a525af1addaaa IP:7001
slots:[5461-10922] (5462 slots) master
M: 194b9b60f0bc7d75cecc89588e3ed1ea64b4014f IP:7002
slots:[10923-16383] (5461 slots) master
S: c5da649d80f975858b65154b83759ec2a95db1f4 IP:7003
replicates 77089374a717e0fe798e1f312b0a525af1addaaa
S: 960d540beacb2367e4c4f35d3a8eec3cd2886278 IP:7004
replicates 194b9b60f0bc7d75cecc89588e3ed1ea64b4014f
S: 068c6505728d0524e38f5185f59a99aa2ff01304 IP:7005
replicates 999e387f1455993e036e50333b79627b87dcc5fd
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 IP:7000)
M: 999e387f1455993e036e50333b79627b87dcc5fd IP:7000
slots:[0-5460] (5461 slots) master
1 additional replica(s)
M: 194b9b60f0bc7d75cecc89588e3ed1ea64b4014f IP:7002
slots:[10923-16383] (5461 slots) master
1 additional replica(s)
S: c5da649d80f975858b65154b83759ec2a95db1f4 IP:7003
slots: (0 slots) slave
replicates 77089374a717e0fe798e1f312b0a525af1addaaa
S: 068c6505728d0524e38f5185f59a99aa2ff01304 IP:7005
slots: (0 slots) slave
replicates 999e387f1455993e036e50333b79627b87dcc5fd
M: 77089374a717e0fe798e1f312b0a525af1addaaa IP:7001
slots:[5461-10922] (5462 slots) master
1 additional replica(s)
S: 960d540beacb2367e4c4f35d3a8eec3cd2886278 IP:7004
slots: (0 slots) slave
replicates 194b9b60f0bc7d75cecc89588e3ed1ea64b4014f
[OK] All nodes agree about slots configuration.
>>> Check for open slots...
>>> Check slots coverage...
[OK] All 16384 slots covered.

15、验证集群状态

redis-cli -c -h 本机IP -p 7000

1	redis-cli -c -h 本机IP -p 7000

此时可看到cluster_state集群状态ok

IP:7000> cluster info
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:96
cluster_stats_messages_pong_sent:107
cluster_stats_messages_sent:203
cluster_stats_messages_ping_received:102
cluster_stats_messages_pong_received:96
cluster_stats_messages_meet_received:5
cluster_stats_messages_received:203

至此redis cluster集群搭建完成

redis cluster在设计的时候，就考虑到了去中心化、去中间件，集群中的每个节点都是平等关系，每个节点都保存各自的数据和整个集群的状态。

redis集群没有并使用传统的一致性哈希来分配数据，而是采用另外一种叫做哈希槽(hash slot)的方式来分配的。redis cluster默认分配了16384个槽(slot)，当我们set一个key时，会用CRC16算法来取模得到所属的槽(slot)，然后将这个key分到哈希槽区间的节点上，具体算法就是：CRC16(key)%16384。

redis集群会把数据存在一个master节点，然后在这个master和其对应的salve之间进行数据同步。当一个master挂掉之后，会启动一个对应的salve节点，充当master。