redis cluster 搭建

redis cluster 是 redis 官方一个高可用解决方案，cluster 中 redis 共有 2^14 （16384）个slot 槽。创建 cluster 后会平均分配到每个 redis 上。cluster 可以对标分片机制。

这里介绍为本机启动6个redis集群服务，并使用 redis-trib.rb 创建 3主3从的 cluster 。

主要步骤：

1. 创建 redis 各实例目录
2. 配置 redis 各实例配置文件
3. 启动 redis 各实例
4. 执行 redis cluster 脚本搭建集群

与普通 redis 实例不同之处在于 2和4步骤配置文件和执行 redis cluster 脚本搭建集群，详细如下：

1、redis 服务数据目录

mkdir cluster
cd cluster
mkdir 6400 6401 6402 6403 6404 6405

2、配置文件

vim 6400/redis.conf

port 6400
dir "/usr/local/redis-3.2.9/cluster/6400"
pidfile "/usr/local/redis-3.2.9/cluster/6400/redis.pid"
logfile "/usr/local/redis-3.2.9/cluster/6400/redis.log"
cluster-enabled yes
cluster-config-file nodes-6400.conf
appendonly yes
dbfilename "dump.rdb"
bind 192.168.33.11
daemonize yes

对应其他 5个配置文件，

cp 6400/redis.conf 6401/redis.conf && sed -i "s/6400/6401/g" 6401/redis.conf
...
cp 6400/redis.conf 6405/redis.conf && sed -i "s/6400/6405/g" 6405/redis.conf

3、启动 redis 服务

./src/redis-server cluster/6400/redis.conf
...
./src/redis-server cluster/6405/redis.conf

4、创建 cluster 集群

redis 很贴心的自带提供 ruby 脚本< ./src/redis-trib.rb > 创建集群，但是需要安装 ruby 相关信息

安装ruby：yum install ruby
安装rubygems：yum install rubygems
安装ruby的redis驱动：gem install redis
可能还需要安装：
安装gcc：yum install gcc
安装zlib：yum install zib

搭建集群了，很简单，执行命令：

./src/redis-trib.rb create --replicas 1 192.168.33.11:6400 192.168.33.11:6401 192.168.33.11:6402 192.168.33.11:6403 192.168.33.11:6404 192.168.33.11:6405

以上命令得到如下结果

>>> Creating cluster
>>> Performing hash slots allocation on 7 nodes...
Using 3 masters:
192.168.33.11:6400
192.168.33.11:6401
192.168.33.11:6402
Adding replica 192.168.33.11:6403 to 192.168.33.11:6400
Adding replica 192.168.33.11:6404 to 192.168.33.11:6401
Adding replica 192.168.33.11:6405 to 192.168.33.11:6402
M: d53cbf49fea9403bd4bb4835c45679d8014c8a11 192.168.33.11:6400
   slots:0-5460 (5461 slots) master
M: da9ffc92d337467975063ac7b82b9b6895b1c93b 192.168.33.11:6401
   slots:5461-10922 (5462 slots) master
M: df494c2c1152d2125ab92148fe772cf92e0e8abd 192.168.33.11:6402
   slots:10923-16383 (5461 slots) master
S: d0296ce856cfe94b7aad0600a7d16c9dc3995608 192.168.33.11:6403
   replicates d53cbf49fea9403bd4bb4835c45679d8014c8a11
S: db28b4113c7faeba02d8f9c5e821d7de00df2f5f 192.168.33.11:6404
   replicates da9ffc92d337467975063ac7b82b9b6895b1c93b
S: 03abf7aaa2b4d3399b26c64d476f1a561215366f 192.168.33.11:6405
   replicates df494c2c1152d2125ab92148fe772cf92e0e8abd
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 192.168.33.11:6400)
M: d53cbf49fea9403bd4bb4835c45679d8014c8a11 192.168.33.11:6400
   slots:0-5460 (5461 slots) master
   2 additional replica(s)
S: 03abf7aaa2b4d3399b26c64d476f1a561215366f 192.168.33.11:6405
   slots: (0 slots) slave
   replicates df494c2c1152d2125ab92148fe772cf92e0e8abd
M: da9ffc92d337467975063ac7b82b9b6895b1c93b 192.168.33.11:6401
   slots:5461-10922 (5462 slots) master
   1 additional replica(s)
S: db28b4113c7faeba02d8f9c5e821d7de00df2f5f 192.168.33.11:6404
   slots: (0 slots) slave
   replicates da9ffc92d337467975063ac7b82b9b6895b1c93b
M: df494c2c1152d2125ab92148fe772cf92e0e8abd 192.168.33.11:6402
   slots:10923-16383 (5461 slots) master
   1 additional replica(s)
S: d0296ce856cfe94b7aad0600a7d16c9dc3995608 192.168.33.11:6403
   slots: (0 slots) slave
   replicates d53cbf49fea9403bd4bb4835c45679d8014c8a11
[OK] All nodes agree about slots configuration.
>>> Check for open slots...
>>> Check slots coverage...
[OK] All 16384 slots covered.

最后查看集群信息

./src/redis-cli -h 192.168.33.11 -p 6400

参考：

http://www.cnblogs.com/rwxwsblog/p/6030606.html
http://www.cnblogs.com/junl0513/p/833f4d3eefc69485958fe83b5c9057d7.html
http://blog.51yip.com/nosql/1726.html 【cluster 命令行管理】