Redis Cluster是Redis官方的集群实现方案,在此之前已经有一些民间的第三方Redis集群解决方案,如Twitter的Twenproxy,豌豆荚的Codis,与其不同的是,Redis Cluster并非使用Porxy的模式来连接集群节点,而是使用无中心节点的模式来组建集群,有一定性能优势也有缺点,本文主要是我调研Redis Cluster的一些知识整理与经验汇总。
首先我们来尝试下搭建一个Redis Cluster集群
前置准备
Redis Cluster需要Redis 3.0及以上版本才支持,此文发布的时候,Redis的最高版本为3.0.5。
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| wget http://download.redis.io/releases/redis-3.0.5.tar.gz tar -xvf redis-3.0.5.tar.gz cd redis-3.0.5 make
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编译完Redis,生成的可执行文件在redis-3.0.5/src
之中,为了方便使用,我们把可执行文件的目录加入PATH之中。
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| vim ~/.bashrc
# 增加以下内容
REDIS_HOME=/home/xiezefan/sofeware/redis-3.0.5/src PATH=$REDIS_HOME:$PATH export PATH
# 保存后让修改生效
source ~/.bashrc
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要创建Redis Cluster,我们还需要安装Ruby以及RubyGems。
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| yum install ruby yum install gcc g++ make automake autoconf curl-devel openssl-devel zlib-devel httpd-devel apr-devel apr-util-devel sqlite-devel yum install ruby-rdoc ruby-devel yum install rubygems gem install redis
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创建集群
此次此时我们需要创建8个节点,端口号7000~7007
复制redis-3.0.5/redis.conf
,修改一下内容
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| mkdir cluster cp ~/sofeware/redis-3.0.5/redis.conf cluster/ vim cluster/redis.conf # 修改以下内容 port 7000 cluster-enabled yes cluster-config-file nodes.conf cluster-node-timeout 5000 appendonly yes
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批量复制7份,修改配置文件的端口号。修改完毕后,分别进入各个节点的目录中启动redis
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| cd 7000 redis-server redis.conf
cd 7001 redis-server redis.conf
# 依次启动7000-7007 ...
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至此,8个Redis全都启动完毕,但是他们还处于彼此互相不知道彼此的阶段。
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| xiezefan@ubuntu:~$ ps -ef | grep redis xiezefan 13372 1 0 20:09 ? 00:00:08 redis-server *:7000 [cluster] xiezefan 13376 1 0 20:09 ? 00:00:08 redis-server *:7001 [cluster] xiezefan 13380 1 0 20:09 ? 00:00:08 redis-server *:7002 [cluster] xiezefan 13382 1 0 20:09 ? 00:00:08 redis-server *:7003 [cluster] xiezefan 13386 1 0 20:09 ? 00:00:08 redis-server *:7004 [cluster] xiezefan 13390 1 0 20:09 ? 00:00:08 redis-server *:7005 [cluster] xiezefan 13394 1 0 20:09 ? 00:00:08 redis-server *:7006 [cluster] xiezefan 13400 1 0 20:09 ? 00:00:08 redis-server *:7007 [cluster]
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下一步,我们要将7000-7005这六个节点连接成一个集群。
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| redis-trib.rb create --replicas 1 10.211.55.4:7000 10.211.55.4:7001 10.211.55.4:7002 10.211.55.4:7003 10.211.55.4:7004 10.211.55.4:7005
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该命令表示,将7000-7006节点创建一个集群,冗余为1,就是3主3从。切记,此处指定的IP会在client发送move命令的时候返回,所以一定要指定为客户端能访问到的IP,例如下面这种IP是不可行的,client拿到的IP就位是127.0.0.1导致一直重定向失败。
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| redis-trib.rb create --replicas 1 127.0.0.1:7000 127.0.0.1:7001 127.0.0.1:7002 127.0.0.1:7003 127.0.0.1:7004 127.0.0.1:7005
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输入后,redis-trib自动分配给出一个slot的分配方案
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| >>> Performing hash slots allocation on 6 nodes... Using 3 masters: 10.211.55.4:7000 10.211.55.4:7001 10.211.55.4:7002 Adding replica 10.211.55.4:7003 to 10.211.55.4:7000 Adding replica 10.211.55.4:7004 to 10.211.55.4:7001 Adding replica 10.211.55.4:7005 to 10.211.55.4:7002 M: 9dfef549f7917794cbabaf96781ed0e19957c1f3 10.211.55.4:7000 slots:0-5460 (5461 slots) master M: c14485e8d7f1f3ec5c505b41fe727b657c951d8d 10.211.55.4:7001 slots:5461-10922 (5462 slots) master M: 8b308093e99f4299b8c18ab1dd81c5a83a3528c6 10.211.55.4:7002 slots:10923-16383 (5461 slots) master S: 632409883570eb5cecf6089583fba64a41d1154f 10.211.55.4:7003 replicates 9dfef549f7917794cbabaf96781ed0e19957c1f3 S: edd31196e2980360b0738c57af95e1a69b0f9c9b 10.211.55.4:7004 replicates c14485e8d7f1f3ec5c505b41fe727b657c951d8d S: 95063a99c5cf2cc4abc51ca1e8ff0f3b8d60271c 10.211.55.4:7005 replicates 8b308093e99f4299b8c18ab1dd81c5a83a3528c6 Can I set the above configuration? (type 'yes' to accept):
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输入yes后,集群自动创建,创建完毕后,通过redis-cli进入任一节点,使用cluster nodes
命令可以查看各个节点的状态
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| xiezefan@ubuntu:~$ redis-cli -p 7000 127.0.0.1:7000>cluster nodes c14485e8d7f1f3ec5c505b41fe727b657c951d8d 10.211.55.4:7001 master - 0 1449060968280 2 connected 5461-10922 95063a99c5cf2cc4abc51ca1e8ff0f3b8d60271c 10.211.55.4:7005 slave 8b308093e99f4299b8c18ab1dd81c5a83a3528c6 0 1449060968280 6 connected edd31196e2980360b0738c57af95e1a69b0f9c9b 10.211.55.4:7004 slave c14485e8d7f1f3ec5c505b41fe727b657c951d8d 0 1449060967274 5 connected 8b308093e99f4299b8c18ab1dd81c5a83a3528c6 10.211.55.4:7002 master - 0 1449060966769 3 connected 10923-16383 632409883570eb5cecf6089583fba64a41d1154f 10.211.55.4:7003 slave 9dfef549f7917794cbabaf96781ed0e19957c1f3 0 1449060967274 4 connected 9dfef549f7917794cbabaf96781ed0e19957c1f3 10.211.55.4:7000 myself,master - 0 0 1 connected 0-5460
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随便输入一个查询指令get user.1
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| 127.0.0.1:7000> get user.1 (error) MOVED 9645 10.211.55.4:7001
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因为user.1所在的solt-9645在7001节点上,cluster给你发送MOVED指令让你去7001节点查找数据,连接redis-cli的时候,使用-c
参数可以指定查询时接收到MOVED指令自动跳转
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| xiezefan@ubuntu:~$ redis-cli -c -p 7000 127.0.0.1:7000> get user.1 -> Redirected to slot [9645] located at 10.211.55.4:7001 (nil)
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集群扩容
现在我们已经有一个包含6个节点的集群,我写了段代码,往集群写入10W条测试数据。
现在模拟机器扩容场景,为集群加入一个master节点7006和一个slave节点7007。
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| redis-trib.rb add-node 10.211.55.4:7006 10.211.55.4:7000
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以上命令将7006节点接入7000所在的集群。接下来,我们为7006增加一个slave节点。
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| redis-trib.rb add-node --slave 10.211.55.4:7007 10.211.55.4:7000
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以上命令表示增加slave节点,将7006的节点加入7000节点所在的集群中作为slave节点,随机依附现有的master节点中slave最少的节点,如果需要再指定特别的master节点,使用
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| redis-trib.rb add-node --slave --master-id 23b412673af0506df6382353e3a65960d5b7e66d 10.211.55.4:7007 10.211.55.4:7000
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其中的23b412673af0506df6382353e3a65960d5b7e66d
是7006节点的id,我们可以通过cluster nodes
命令查看节点的id。
接下来我们用坐负载均衡,Slot是Redis Cluster数据承载的最小单位,我们可以指定将一定范围的Slot转移到新的节点来实现负载均衡。
Redis Cluster转移一个Slot的步骤是:
- 在目标节点上声明将从源节点上迁入Slot
CLUSTER SETSLOT <slot> IMPORTING <source_node_id>
- 在源节点上声明将往目标节点迁出Slot
CLUSTER SETSLOT <slot> IMPORTING <source_node_id>
- 批量从源节点获取KEY
CLUSTER GETKEYSINSLOT <slot> <count>
- 将获取的Key迁移到目标节点
MIGRATE <target_ip> <target_port> <key_name> 0 <timeout>
- 重复步骤3,4直到所有数据迁移完毕
- 分别向双方节点发送
CLUSTER SETSLOT <slot> NODE <target_node_id>
,该命令将会广播给集群其他节点,已经将Slot转移到目标节点。
- 等待集群状态变为OK
CLUSTER INFO
中的 cluster_state = ok
我编写了一个脚本来批量迁移Slot
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| #!/bin/bash source_host=$1 # 源节点HOST source_port=$2 # 源节点端口 target_host=$3 # 目标节点HOST target_port=$4 # 目标节点端口 start_slot=$5 # 迁移节点的其实范围 end_slot=$6 # 迁移节点的结束范围
for slot in `seq ${start_slot} ${end_slot}` do redis-cli -c -h ${target_host} -p ${target_port} cluster setslot ${slot} importing `redis-cli -c -h ${source_host} -p ${source_port} cluster nodes | grep ${source_port} | awk '{print $1}'` echo "Setslot importing ${slot} to ${target_host}:${target_port} success" redis-cli -c -h ${source_host} -p ${source_port} cluster setslot ${slot} migrating `redis-cli -c -h ${target_host} -p ${target_port} cluster nodes | grep ${target_port} | awk '{print $1}'` echo "Setslot migrating ${slot} from ${source_host}:${source_port} success"
while [ 1 -eq 1 ] do allkeys=`redis-cli -c -h ${source_host} -p ${source_port} cluster getkeysinslot ${slot} 10` if [ -z "${allkeys}" ] then redis-cli -c -h ${source_host} -p ${source_port} cluster setslot ${slot} node `redis-cli -c -h ${target_host} -p ${target_port} cluster nodes | grep ${target_port} | awk '{print $1}'` redis-cli -c -h ${target_host} -p ${target_port} cluster setslot ${slot} node `redis-cli -c -h ${source_host} -p ${target_port} cluster nodes | grep ${target_port} | awk '{print $1}'` echo "Migrate slot ${slot} finish" break else for key in ${allkeys} do redis-cli -c -h ${source_host} -p ${source_port} migrate ${target_host} ${target_port} ${key} 0 5000 echo "Migrate slot ${slot} key ${key} success" done fi done done
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执行命令 bash rebalance-cluster.sh 10.211.55.4 7000 10.211.55.4 7006 0 1000
将7000节点上0-1000这个范围内的Slot转移到7006节点,通过cluster nodes
命令我们可以看到0-1000这个区间是slot已经从7000转移到7006
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| xiezefan@ubuntu:~/sheel$ redis-cli -c -p 7000 cluster nodes 23b412673af0506df6382353e3a65960d5b7e66d 10.211.55.4:7006 master - 0 1449064402389 7 connected 0-1000 0c2954d21d7bcdae333f4fdecf468ce05aa25544 10.211.55.4:7001 master - 0 1449064400372 2 connected 5461-10922 384a3bb5bd9ecb2fc7db75c866abc715d7966f82 10.211.55.4:7002 master - 0 1449064401381 3 connected 10923-16383 c3e09d286ef2dce49843268b20832d65a5d516a1 10.211.55.4:7004 slave 0c2954d21d7bcdae333f4fdecf468ce05aa25544 0 1449064401885 5 connected 50737b4a91443ab1a34eec4ef99d4f6fe5d358f4 10.211.55.4:7005 slave 384a3bb5bd9ecb2fc7db75c866abc715d7966f82 0 1449064402389 6 connected 3c62cc6664bba378cceb8ae8e02f5d727deafe9d 10.211.55.4:7007 slave 23b412673af0506df6382353e3a65960d5b7e66d 0 1449064400878 7 connected d6441916dcd89cbf431465d92dfc0eb3dd235295 10.211.55.4:7003 slave 6ee21c5d93a6d2f293a2df1b37e8c9c27cb55ad8 0 1449064402389 4 connected 6ee21c5d93a6d2f293a2df1b37e8c9c27cb55ad8 10.211.55.4:7000 myself,master - 0 0 1 connected 1001-5460
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参考文章