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集群架构
(1)所有的redis节点彼此互联(PING-PONG机制),内部使用二进制协议优化传输速度和带宽. (2)节点的fail是通过集群中超过半数的节点检测失效时才生效.
(3)客户端与redis节点直连,不需要中间proxy层.客户端不需要连接集群所有节点,连接集群中任何一个可用节点即可
(4)redis-cluster把所有的物理节点映射到[0-16383]slot（插槽）上,cluster 负责维护node<->slot<->value
准备环境 创建一个目录，存放集群的配置文件
[root@master redis]# mkdir redis-cluster
[root@master redis]# cd redis-cluster/
[root@master redis-cluster]# mkdir 6380
[root@master redis-cluster]# mkdir 6381
[root@master redis-cluster]# mkdir 6382
[root@master redis-cluster]# pwd
/opt/redis/redis-cluster
拷贝安装源码中的redis.conf刚创建好的三个目录中 [root@master redis-cluster]# cp /opt/redis/redis-3.2.1/redis.conf /opt/redis/redis-cluster/6380/
[root@master redis-cluster]# cp /opt/redis/redis-3.2.1/redis.conf /opt/redis/redis-cluster/6381/
[root@master redis-cluster]# cp /opt/redis/redis-3.2.1/redis.conf /opt/redis/redis-cluster/6382/
分别进入这三个目录，修改配置文件redis.conf 1、将端口分别设置为：6380、6381、6382
2、设置pidfile文件为不同的路径
3、开启集群，cluster-enabled yes
4、指定集群的配置文件，cluster-config-file "nodes-xxxx.conf"
以6380为例：
[root@master redis-master-slave]# vim 6380/redis.conf
启动redis-server
[root@master redis-cluster]# /usr/local/bin/redis-server /opt/redis/redis-cluster/6380/redis.conf
[root@master redis-cluster]# /usr/local/bin/redis-server /opt/redis/redis-cluster/6381/redis.conf
[root@master redis-cluster]# /usr/local/bin/redis-server /opt/redis/redis-cluster/6382/redis.conf
[root@master redis-cluster]# ps -ef | grep redis root 2948 1 0 11:11 ? 00:00:00 /usr/local/bin/redis-server 127.0.0.1:6380 [cluster]
root 2970 1 0 11:16 ? 00:00:00 /usr/local/bin/redis-server 127.0.0.1:6381 [cluster]
root 2974 1 0 11:16 ? 00:00:00 /usr/local/bin/redis-server 127.0.0.1:6382 [cluster]
创建redis集群 创建集群要使用redis-trib.rb脚本，执行此脚本查看使用方法
[root@master redis-cluster]# /opt/redis/redis-3.2.1/src/redis-trib.rb
Usage: redis-trib <command> <options> <arguments ...>
del-node host:port node_id
info host:port
rebalance host:port
--timeout <arg>
--auto-weights
--pipeline <arg>
--threshold <arg>
--weight <arg>
--simulate
--use-empty-masters
check host:port
reshard host:port
--timeout <arg>
--to <arg>
--pipeline <arg>
--from <arg>
--slots <arg>
--yes
call host:port command arg arg .. arg
import host:port
--copy
--from <arg>
--replace
help (show this help)
set-timeout host:port milliseconds
create host1:port1 ... hostN:portN
--replicas <arg>
add-node new_host:new_port existing_host:existing_port
--slave
--master-id <arg>
fix host:port
--timeout <arg>
For check, fix, reshard, del-node, set-timeout you can specify the host and port of any working node in the cluster.
使用redis-trib.rb create创建集群，--replicas 0：指定了从数据的数量为0 注意：这里不能使用127.0.0.1，否则在Jedis客户端使用时无法连接到！
[root@master redis-cluster]# /opt/redis/redis-3.2.1/src/redis-trib.rb create --replicas 0 192.168.56.101:6380 192.168.56.101:6381 192.168.56.101:6382 >>> Creating cluster
[ERR] Sorry, can't connect to node 192.168.56.101:6380
修改刚创建的三个redis.conf配置文件中的bind bind 192.168.56.101
重启redis-server [root@master redis-cluster]# /usr/local/bin/redis-server /opt/redis/redis-cluster/6380/redis.conf
[root@master redis-cluster]# /usr/local/bin/redis-server /opt/redis/redis-cluster/6381/redis.conf
[root@master redis-cluster]# /usr/local/bin/redis-server /opt/redis/redis-cluster/6382/redis.conf
[root@master redis-cluster]# ps -ef | grep redis
root 3756 1 0 13:11 ? 00:00:00 /usr/local/bin/redis-server 192.168.56.101:6380 [cluster]
root 3760 1 0 13:11 ? 00:00:00 /usr/local/bin/redis-server 192.168.56.101:6381 [cluster]
root 3764 1 0 13:11 ? 00:00:00 /usr/local/bin/redis-server 192.168.56.101:6382 [cluster]
再创建集群 [root@master redis-cluster]# /opt/redis/redis-3.2.1/src/redis-trib.rb create --replicas 0 192.168.56.101:6380 192.168.56.101:6381 192.168.56.101:6382
>>> Creating cluster
>>> Performing hash slots allocation on 3 nodes...
Using 3 masters:
192.168.56.101:6380
192.168.56.101:6381
192.168.56.101:6382
M: 8c45a68a798aed7c1ed5e636f2899709717952c8 192.168.56.101:6380
slots:0-5460 (5461 slots) master
M: c9267b81af4bb2c186d07c5ebc777a4b8551069a 192.168.56.101:6381
slots:5461-10922 (5462 slots) master
M: 16c6db308b37be4d4dd337cd62ea1b676672e096 192.168.56.101:6382
slots:10923-16383 (5461 slots) master
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 192.168.56.101:6380)
M: 8c45a68a798aed7c1ed5e636f2899709717952c8 192.168.56.101:6380
slots:0-5460 (5461 slots) master
M: c9267b81af4bb2c186d07c5ebc777a4b8551069a 192.168.56.101:6381
slots:5461-10922 (5462 slots) master
M: 16c6db308b37be4d4dd337cd62ea1b676672e096 192.168.56.101:6382
slots:10923-16383 (5461 slots) master【集群及槽信息】
[OK] All nodes agree about slots configuration.
>>> Check for open slots...
>>> Check slots coverage...
[OK] All 16384 slots covered.
测试集群 [root@master hadoop]# /usr/local/bin/redis-cli -h 192.168.56.101 -p 6380
192.168.56.101:6380> keys *
(empty list or set)
192.168.56.101:6380> set k1 123
(error) MOVED 12706 192.168.56.101:6382
因为k1的hash槽信息是在6382上，现在使用redis-cli连接的6380，无法完成set操作，需要客户端跟踪重定向，使用-c参数
[root@master hadoop]# /usr/local/bin/redis-cli -h 192.168.56.101 -p 6380 -c
192.168.56.101:6380> set k1 123
-> Redirected to slot [12706] located at 192.168.56.101:6382
OK
获取数据 k1的hash槽信息在6382上，在6382上可以直接获取，在其他节点还是要重定向去获取
[root@master hadoop]# /usr/local/bin/redis-cli -h 192.168.56.101 -p 6380 -c
192.168.56.101:6380> get k1
-> Redirected to slot [12706] located at 192.168.56.101:6382
"123"
[root@master hadoop]# /usr/local/bin/redis-cli -h 192.168.56.101 -p 6382 -c
192.168.56.101:6382> get k1
"123"
执行redis-trib.rb脚本可能遇到的问题 1、/usr/bin/env: ruby: 没有那个文件或目录
[root@master redis-cluster]# /opt/redis/redis-3.2.1/src/redis-trib.rb
/usr/bin/env: ruby: 没有那个文件或目录
解决方案：由于redis-trib.rb是用ruby语言编写，所以需要安装ruby环境，这里推荐使用yum install ruby
2、redis-trib.rb:24:in `require': no such file to load -- rubygems [root@master redis-cluster]# /opt/redis/redis-3.2.1/src/redis-trib.rb
/opt/redis/redis-3.2.1/src/redis-trib.rb:24:in `require': no such file to load -- rubygems (LoadError)
from /opt/redis/redis-3.2.1/src/redis-trib.rb:24
解决方案：yum install rubygems
3、/usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require': no such file to load -- redis (LoadError) [root@master redis-cluster]# /opt/redis/redis-3.2.1/src/redis-trib.rb
/usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require': no such file to load -- redis (LoadError)
from /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
from /opt/redis/redis-3.2.1/src/redis-trib.rb:25
解决方案：缺少redis的接口，使用gem install redis或gem install redis --version 3.2.1
[root@master redis-cluster]# gem install redis --version 3.2.1
Successfully installed redis-3.2.1
1 gem installed
Installing ri documentation for redis-3.2.1...
Installing RDoc documentation for redis-3.2.1...
备注： 如果连接不上gem服务器安装，就手动下载并安装
gem install redis --version 3.0.0
ERROR: Could not find a valid gem 'redis' (= 3.0.0) in any repository
ERROR: While executing gem ... (Gem::RemoteFetcher::FetchError)
需要手工下载并安装：
wget https://rubygems.global.ssl.fastly.net/gems/redis-3.2.1.gem
gem install -l ./redis-3.2.1.gem
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