redis集群
ruby环境
redis集群管理工具redis-trib.rb依赖ruby环境，首先需要安装ruby环境：
安装ruby
yum install ruby
yum install rubygems
安装ruby和redis的接口程序
拷贝redis-3.0.0.gem至/usr/local下
执行：
gem install /usr/local/redis-3.0.0.gem
创建集群：
集群结点规划
这里在同一台服务器用不同的端口表示不同的redis服务器，如下：
主节点：192.168.101.3:7001 192.168.101.3:7002 192.168.101.3:7003
从节点：192.168.101.3:7004 192.168.101.3:7005 192.168.101.3:7006
在/usr/local下创建redis-cluster目录，其下创建7001、7002...7006目录，如下：
将redis安装目录bin下的文件拷贝到每个700X目录内，同时将redis源码目录src下的redis-trib.rb拷贝到redis-cluster目录下。
修改每个700X目录下的redis.conf配置文件：
port XXXX
bind 192.168.101.3
cluster-enabled yes
启动每个结点redis服务
分别进入7001、7002、...7006目录，执行：
./redis-server ./redis.conf
查看redis进程：
执行创建集群命令
执行redis-trib.rb，此脚本是ruby脚本，它依赖ruby环境。
./redis-trib.rb create --replicas 1 192.168.101.3:7001 192.168.101.3:7002 192.168.101.3:7003 192.168.101.3:7004 192.168.101.3:7005 192.168.101.3:7006
说明：
redis集群至少需要3个主节点，每个主节点有一个从节点总共6个节点
replicas指定为1表示每个主节点有一个从节点
注意：
如果执行时报如下错误：
[ERR] Node XXXXXX is not empty.
Either the node already knows other nodes (check with CLUSTER NODES) or contains some key in database 0
解决方法是删除生成的配置文件nodes.conf，如果不行则说明现在创建的结点包括了旧集群的结点信息，需要删除redis的持久化文件后再重启redis，比如：appendonly.aof、dump.rdb
创建集群输出如下：
>>> Creating cluster
Connecting to node 192.168.101.3:7001: OK
Connecting to node 192.168.101.3:7002: OK
Connecting to node 192.168.101.3:7003: OK
Connecting to node 192.168.101.3:7004: OK
Connecting to node 192.168.101.3:7005: OK
Connecting to node 192.168.101.3:7006: OK
>>> Performing hash slots allocation on 6 nodes...
Using 3 masters:
192.168.101.3:7001
192.168.101.3:7002
192.168.101.3:7003
Adding replica 192.168.101.3:7004 to 192.168.101.3:7001
Adding replica 192.168.101.3:7005 to 192.168.101.3:7002
Adding replica 192.168.101.3:7006 to 192.168.101.3:7003
M: cad9f7413ec6842c971dbcc2c48b4ca959eb5db4 192.168.101.3:7001
slots:0-5460 (5461 slots) master
M: 4e7c2b02f0c4f4cfe306d6ad13e0cfee90bf5841 192.168.101.3:7002
slots:5461-10922 (5462 slots) master
M: 1a8420896c3ff60b70c716e8480de8e50749ee65 192.168.101.3:7003
slots:10923-16383 (5461 slots) master
S: 69d94b4963fd94f315fba2b9f12fae1278184fe8 192.168.101.3:7004
replicates cad9f7413ec6842c971dbcc2c48b4ca959eb5db4
S: d2421a820cc23e17a01b597866fd0f750b698ac5 192.168.101.3:7005
replicates 4e7c2b02f0c4f4cfe306d6ad13e0cfee90bf5841
S: 444e7bedbdfa40714ee55cd3086b8f0d5511fe54 192.168.101.3:7006
replicates 1a8420896c3ff60b70c716e8480de8e50749ee65
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 192.168.101.3:7001)
M: cad9f7413ec6842c971dbcc2c48b4ca959eb5db4 192.168.101.3:7001
slots:0-5460 (5461 slots) master
M: 4e7c2b02f0c4f4cfe306d6ad13e0cfee90bf5841 192.168.101.3:7002
slots:5461-10922 (5462 slots) master
M: 1a8420896c3ff60b70c716e8480de8e50749ee65 192.168.101.3:7003
slots:10923-16383 (5461 slots) master
M: 69d94b4963fd94f315fba2b9f12fae1278184fe8 192.168.101.3:7004
slots: (0 slots) master
replicates cad9f7413ec6842c971dbcc2c48b4ca959eb5db4
M: d2421a820cc23e17a01b597866fd0f750b698ac5 192.168.101.3:7005
slots: (0 slots) master
replicates 4e7c2b02f0c4f4cfe306d6ad13e0cfee90bf5841
M: 444e7bedbdfa40714ee55cd3086b8f0d5511fe54 192.168.101.3:7006
slots: (0 slots) master
replicates 1a8420896c3ff60b70c716e8480de8e50749ee65
[OK] All nodes agree about slots configuration.
>>> Check for open slots...
>>> Check slots coverage...
[OK] All 16384 slots covered.查询集群信息
集群创建成功登陆任意redis节点查询集群中的节点情况。
客户端以集群方式登陆：
说明：
./redis-cli -c -h 192.168.101.3 -p 7001
其中-c表示以集群方式连接redis，-h指定ip地址，-p指定端口号
cluster nodes 查询集群结点信息
cluster info 查询集群状态信息
