如何手动创建与自动创建redis集群

这篇文章给大家分享的是手动创建与自动创建redis集群的方法，相信大部分人都还没学会这个技能，为了让大家学会，给大家总结了以下内容，话不多说，一起往下看吧。

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手动创建：

环境描述：一台机器启动六个节点，3个主节点，3个从节点。
安装：
tar -zxvf redis-3.2.10.tar.gz
mv redis-3.2.10 /usr/local/redis
yum install gcc* tcl -y
make && make test
修改配置文件：
vi /usr/local/redis/redis.conf

**要改的地方**
daemonize yes
port 7000
cluster-enabled yes
cluster-config-file nodes-7000.conf . //这个编号最好是等于你的端口号
cluster-node-timeout 5000

mkdir /usr/local/cluster-test/  //同时复制配置文件，且修改端口及参数

**在/usr/local/cluster-test/下创建**
mkdir 7000
mkdir 7001
mkdir 7002
mkdir 7003
mkdir 7004
mkdir 7005

启动服务：

./redis-server /usr/local/cluster-test/7000/redis.conf
./redis-server /usr/local/cluster-test/7001/redis.conf
./redis-server /usr/local/cluster-test/7002/redis.conf
./redis-server /usr/local/cluster-test/7003/redis.conf
./redis-server /usr/local/cluster-test/7004/redis.conf
./redis-server /usr/local/cluster-test/7005/redis.conf

netstat -anput | grep redis
[root@localhost src]# ./redis-cli -h 127.0.0.1 -p 7000

127.0.0.1:7000> CLUSTER MEET 127.0.0.1 7000
127.0.0.1:7000> CLUSTER MEET 127.0.0.1 7001
127.0.0.1:7000> CLUSTER MEET 127.0.0.1 7002
127.0.0.1:7000> CLUSTER MEET 127.0.0.1 7003
127.0.0.1:7000> CLUSTER MEET 127.0.0.1 7004
127.0.0.1:7000> CLUSTER MEET 127.0.0.1 7005
127.0.0.1:7000> CLUSTER NODES
127.0.0.1:7000> CLUSTER INFO . //cluter开始的时候是fail

给三个主节点分配槽点：

redis-cli -h 127.0.0.1 -p 7000 cluster addslots {0..5461}
redis-cli -h 127.0.0.1 -p 7001 cluster addslots {5462..10922}
redis-cli -h 127.0.0.1 -p 7002 cluster addslots {10923..16383}

设置从节点：
[root@localhost src]# ./redis-cli -p 7003
127.0.0.1:7003> CLUSTER REPLICATE
8573e44492c6ba0713e36545202459974cc18cf7
[root@localhost src]# ./redis-cli -p 7004
127.0.0.1:7004> CLUSTER REPLICATE
59d75c9a0b599265d0ac123cc99f18050df5afa3
[root@localhost src]# ./redis-cli -p 7005
127.0.0.1:7005> CLUSTER REPLICATE
607f5472bdd9f581ad16b960244ee7ba18fb5a1f
[root@localhost src]# ./redis-cli -p 7000
127.0.0.1:7000> CLUSTER INFO

cluster_state:ok //成功
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:5
cluster_my_epoch:3
cluster_stats_messages_sent:7306
cluster_stats_messages_received:7306

自动创建：

环境描述：一台机器启动六个节点，3个主节点，3个从节点。
安装：
tar -zxvf redis-3.2.10.tar.gz
mv redis-3.2.10 /usr/local/redis
yum install gcc* tcl -y
make && make test
修改配置文件：
vi /usr/local/redis/redis.conf

daemonize yes
port 7000
cluster-enabled yes
cluster-config-file nodes-7000.conf . //这个编号最好是等于你的端口号
cluster-node-timeout 5000
appendonly yes

mkdir /usr/local/cluster-test/  //同时复制配置文件，且修改端口及参数

mkdir 7000
mkdir 7001
mkdir 7002
mkdir 7003
mkdir 7004
mkdir 7005

启动服务：

redis-server /usr/local/cluster-test/7000/redis.conf
redis-server /usr/local/cluster-test/7001/redis.conf
redis-server /usr/local/cluster-test/7002/redis.conf
redis-server /usr/local/cluster-test/7003/redis.conf
redis-server /usr/local/cluster-test/7004/redis.conf
redis-server /usr/local/cluster-test/7005/redis.conf

[root@localhost ～]#netstat -anput | grep redis
将6个节点连在一起构成集群
需要用到的命令就是redis-trib.rb,这是官方的一个用ruby写的一个操作redis cluster的命
令，所以，你的机器上需要安装ruby。我们先试一下这个命令：
[root@web3 7005]# yum -y install  rpm-build openssl openssl-devel
[root@localhost ruby]# tar -zxvf ruby-2.3.1.tar.gz
[root@localhost ruby]#./configure --prefix=/usr/local/ruby
[root@localhost ruby]#make && make install
[root@localhost ruby]#ln -s /usr/local/ruby/bin/* /usr/local/bin/
[root@localhost ～]# ln /usr/local/redis/src/redis-trib.rb /usr/local/bin/
[root@localhost ～]#gem install redis-3.3.0.gem
[root@localhost ～]# gem list redis
因为我们要新建集群, 所以这里使用create命令. --replicas 1 参数表示为每个主节点创建一
个从节点. 其他参数是实例的地址集合。

[root@localhost src]# 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

Creating cluster
Connecting to node 127.0.0.1:7000: OK
Connecting to node 127.0.0.1:7001: OK
Connecting to node 127.0.0.1:7002: OK
Connecting to node 127.0.0.1:7003: OK
Connecting to node 127.0.0.1:7004: OK
Connecting to node 127.0.0.1:7005: OK
Performing hash slots allocation on 6 nodes...
Using 3 masters:
127.0.0.1:7000
127.0.0.1:7001
127.0.0.1:7002
Adding replica 127.0.0.1:7003 to 127.0.0.1:7000
Adding replica 127.0.0.1:7004 to 127.0.0.1:7001
Adding replica 127.0.0.1:7005 to 127.0.0.1:7002
M: 3707debcbe7be66d4a1968eaf3a5ffaf4308efa4 127.0.0.1:7000
slots:0-5460 (5461 slots) master
M: cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c 127.0.0.1:7001
slots:5461-10922 (5462 slots) master
M: dfa0754c7854a874a6ebd2613b86140ad97701fc 127.0.0.1:7002
slots:10923-16383 (5461 slots) master
S: d2237fdcfbba672de766b913d1186cebcb6e1761 127.0.0.1:7003
replicates 3707debcbe7be66d4a1968eaf3a5ffaf4308efa4
S: 4b4aef8b48c427a3c903518339d53b6447c58b93 127.0.0.1:7004
replicates cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c
S: 30858dbf483b61b9838d5c1f853a60beaa4e7afd 127.0.0.1:7005
replicates dfa0754c7854a874a6ebd2613b86140ad97701fc
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 127.0.0.1:7000)
M: 3707debcbe7be66d4a1968eaf3a5ffaf4308efa4 127.0.0.1:7000
slots:0-5460 (5461 slots) master
M: cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c 127.0.0.1:7001
slots:5461-10922 (5462 slots) master
M: dfa0754c7854a874a6ebd2613b86140ad97701fc 127.0.0.1:7002
slots:10923-16383 (5461 slots) master
M: d2237fdcfbba672de766b913d1186cebcb6e1761 127.0.0.1:7003
slots: (0 slots) master
replicates 3707debcbe7be66d4a1968eaf3a5ffaf4308efa4
M: 4b4aef8b48c427a3c903518339d53b6447c58b93 127.0.0.1:7004
slots: (0 slots) master
replicates cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c
M: 30858dbf483b61b9838d5c1f853a60beaa4e7afd 127.0.0.1:7005
slots: (0 slots) master
replicates dfa0754c7854a874a6ebd2613b86140ad97701fc
[OK] All nodes agree about slots configuration.
Check for open slots...
Check slots coverage...
[OK] All 16384 slots covered.
Redis-trib会提示你做了什么配置, 输入yes接受. 集群就被配置和加入了, 意思是, 实例
会经过互相交流后启动。
测试集群的状态：
[root@localhost 7000]# redis-trib.rb check 127.0.0.1:7000
可以看到有3个主节点，3个从节点。每个节点都是成功的连接状态
3个主节点［M］是：
7000 (3707debcbe7be66d4a1968eaf3a5ffaf4308efa4)
7001 (cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c)
7002 (dfa0754c7854a874a6ebd2613b86140ad97701fc)
3个从节点［S］是：
7003 (d2237fdcfbba672de766b913d1186cebcb6e1761)->7000
7004 (4b4aef8b48c427a3c903518339d53b6447c58b93)->7001
7005 (30858dbf483b61b9838d5c1f853a60beaa4e7afd) ->7002
测试连接集群
刚才集群搭建成功了。按照redis cluster的特点，它是去中心化，每个节点都是对等的，所
以，你连接哪个节点都可以获取和设置数据，我们来试一下。 redis-cli是redis默认的客户
端工具，启动时加上-c参数，就可以连接到集群。 连接任意一个节点端口：
[root@web3 7000]# redis-cli -c -p 7000
127.0.0.1:7000>
设置一个值：
127.0.0.1:7000> set my_name linux
-> Redirected to slot [12803] located at 127.0.0.1:7002
OK
127.0.0.1:7002> get my_name
"linux"
127.0.0.1:7002>
前面理论知识我们知道了，分配key的时候，它会使用CRC16('my_name')%16384算法，
来计算，将这个key放到哪个节点，这里分配到了12803 slot 就分配到了7002(10923-
16383)这个节点上。
Redirected to slot [12803] located at 127.0.0.1:7002
redis cluster 采用的方式很直接，它直接跳转到7002节点了，而不是还在自身的7000节
点。 现在我们连接7005这个从节点：

[root@web3 7000]# redis-cli -c -p 7005

127.0.0.1:7005> get my_name
-> Redirected to slot [12803] located at 127.0.0.1:7002
"linux"
127.0.0.1:7002>
我们同样是获取my_name的值，它同样也是跳转到了7002上。 我们再尝试一些其他的可
以：
127.0.0.1:7002> set age 123
-> Redirected to slot [741] located at 127.0.0.1:7000
OK
127.0.0.1:7000> set height 565
-> Redirected to slot [8223] located at 127.0.0.1:7001
OK
127.0.0.1:7001> set sex 1
-> Redirected to slot [2584] located at 127.0.0.1:7000
OK
127.0.0.1:7000> set home china
-> Redirected to slot [10814] located at 127.0.0.1:7001
OK
127.0.0.1:7001> set city shanghai
-> Redirected to slot [11479] located at 127.0.0.1:7002
OK
127.0.0.1:7002> set citylocate shanghaipudong
OK
127.0.0.1:7001> set wsdwxzx hhh
-> Redirected to slot [15487] located at 127.0.0.1:7002
OK
127.0.0.1:7002> zadd erew 333 rrr
-> Redirected to slot [10576] located at 127.0.0.1:7001
(integer) 1
127.0.0.1:7000> zrange erew 0 -1
-> Redirected to slot [10576] located at 127.0.0.1:7001
1) "rrr"
127.0.0.1:7001>
128.~~~~
可以看出，数据都会在7000-7002 这3个主节点来跳转存储。
测试集群中的节点挂掉
上面我们建立来了一个集群。3个主节点［7000-7002］提供数据存粗和读取，3个从节点
［7003-7005］则是负责把［7000-7002］的数据同步到自己的节点上来，我们来看一下
［7003-7005］的appendonly.aof的内容。看看是不是不这样：
`[root@web3 7005]# cd /usr/local/cluster-test/7003`
`[root@web3 7003]# vi appendonly.aof`
*2
$6
SELECT
$1
0
*3
$3
set
$3
age
$3
123
*3
$3
set
$3
sex
$1
1
*3
$3
set
$3
job
$3
php
我们看下，的确是从7000节点上同步过来的数据，7004，7005也是。
下面，我们先来模拟其中一台Master主服务器挂掉的情况。
`[root@web3 7003]# ps -ef|grep redis`
root 11380 1 0 07:37 ? 00:00:03 redis-server *:7000 [cluster]
root 11384 1 0 07:37 ? 00:00:03 redis-server *:7001 [cluster]
root 11388 1 0 07:37 ? 00:00:03 redis-server *:7002 [cluster]
root 11392 1 0 07:37 ? 00:00:03 redis-server *:7003 [cluster]
root 11396 1 0 07:37 ? 00:00:04 redis-server *:7004 [cluster]
root 11400 1 0 07:37 ? 00:00:03 redis-server *:7005 [cluster]
好，安装前面的理论，7000主节点挂掉了，那么这个时候，7000的从节点只有7003一个，
肯定7003就会被选举称Master节点了：
`[root@web3 7003]# kill 11380`
`[root@web3 7003]# redis-trib.rb check 127.0.0.1:7000`
Connecting to node 127.0.0.1:7000: [ERR] Sorry, can't connect to node
127.0.0.1:7000
`[root@web3 7003]# redis-trib.rb check 127.0.0.1:7001`
Connecting to node 127.0.0.1:7001: OK
Connecting to node 127.0.0.1:7004: OK
Connecting to node 127.0.0.1:7005: OK
Connecting to node 127.0.0.1:7003: OK
Connecting to node 127.0.0.1:7002: OK
 Performing Cluster Check (using node 127.0.0.1:7001)
M: cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c 127.0.0.1:7001
slots:5461-10922 (5462 slots) master
1 additional replica(s)
S: 4b4aef8b48c427a3c903518339d53b6447c58b93 127.0.0.1:7004
slots: (0 slots) slave
replicates cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c
S: 30858dbf483b61b9838d5c1f853a60beaa4e7afd 127.0.0.1:7005
slots: (0 slots) slave
replicates dfa0754c7854a874a6ebd2613b86140ad97701fc
M: d2237fdcfbba672de766b913d1186cebcb6e1761 127.0.0.1:7003
slots:0-5460 (5461 slots) master
0 additional replica(s)
M: dfa0754c7854a874a6ebd2613b86140ad97701fc 127.0.0.1:7002
slots:10923-16383 (5461 slots) master
1 additional replica(s)
[OK] All nodes agree about slots configuration.
 Check for open slots...
Check slots coverage...
[OK] All 16384 slots covered.
看了下，上面有了三个M节点了，果真，7003被选取成了替代7000成为主节点了。那我们
来获取原先存在7000节点的数据：
`[root@web3 7003]# redis-cli -c -p 7001`
127.0.0.1:7001> get sex
 Redirected to slot [2584] located at 127.0.0.1:7003
"1"
127.0.0.1:7003>
数据果真没有丢失，而是从7003上面获取了。
我们再来模拟 7000节点重新启动了的情况，那么它还会自动加入到集群中吗？那么，7000
这个节点上充当什么角色呢？ 我们试一下： 重新启动 7000 节点：
[root@web3 7003]# cd ../7000
[root@web3 7000]# ll
total 56
-rw-r--r-- 1 root root 114 Oct 17 08:16 appendonly.aof
-rw-r--r-- 1 root root 43 Oct 17 08:37 dump.rdb
-rw-r--r-- 1 root root 745 Oct 17 08:00 nodes.conf
-rw-r--r-- 1 root root 41550 Oct 17 07:37 redis.conf
[root@web3 7000]# redis-server redis.conf
启动好了，现在，再来检查一下集群：
redis-trib.rb check 127.0.0.1:7001
`[root@web3 7000]# redis-trib.rb check 127.0.0.1:7001`
Connecting to node 127.0.0.1:7001: OK
Connecting to node 127.0.0.1:7004: OK
Connecting to node 127.0.0.1:7005: OK
Connecting to node 127.0.0.1:7003: OK
Connecting to node 127.0.0.1:7000: OK
Connecting to node 127.0.0.1:7002: OK
 Performing Cluster Check (using node 127.0.0.1:7001)
M: cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c 127.0.0.1:7001
slots:5461-10922 (5462 slots) master
1 additional replica(s)
S: 4b4aef8b48c427a3c903518339d53b6447c58b93 127.0.0.1:7004
slots: (0 slots) slave
replicates cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c
S: 30858dbf483b61b9838d5c1f853a60beaa4e7afd 127.0.0.1:7005
slots: (0 slots) slave
replicates dfa0754c7854a874a6ebd2613b86140ad97701fc
M: d2237fdcfbba672de766b913d1186cebcb6e1761 127.0.0.1:7003
slots:0-5460 (5461 slots) master
1 additional replica(s)
S: 3707debcbe7be66d4a1968eaf3a5ffaf4308efa4 127.0.0.1:7000
slots: (0 slots) slave
replicates d2237fdcfbba672de766b913d1186cebcb6e1761
M: dfa0754c7854a874a6ebd2613b86140ad97701fc 127.0.0.1:7002
slots:10923-16383 (5461 slots) master
1 additional replica(s)
[OK] All nodes agree about slots configuration.
 Check for open slots...
 Check slots coverage...
[OK] All 16384 slots covered.
你看，7000节点启动起来了，它却作为了 7003 的从节点了。

-----

de 127.0.0.1:7000: OK
Connecting to node 127.0.0.1:7002: OK
Connecting to node 127.0.0.1:7005: OK
Connecting to node 127.0.0.1:7003: OK
 Performing Cluster Check (using node 127.0.0.1:7006)
M: efc3131fbdc6cf929720e0e0f7136cae85657481 127.0.0.1:7006
slots: (0 slots) master
0 additional replica(s)
M: cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c 127.0.0.1:7001
slots:5461-10922 (5462 slots) master
1 additional replica(s)
S: 4b4aef8b48c427a3c903518339d53b6447c58b93 127.0.0.1:7004
slots: (0 slots) slave
replicates cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c
S: 3707debcbe7be66d4a1968eaf3a5ffaf4308efa4 127.0.0.1:7000
slots: (0 slots) slave
replicates d2237fdcfbba672de766b913d1186cebcb6e1761
M: dfa0754c7854a874a6ebd2613b86140ad97701fc 127.0.0.1:7002
slots:10923-16383 (5461 slots) master
1 additional replica(s)
S: 30858dbf483b61b9838d5c1f853a60beaa4e7afd 127.0.0.1:7005
slots: (0 slots) slave
replicates dfa0754c7854a874a6ebd2613b86140ad97701fc
M: d2237fdcfbba672de766b913d1186cebcb6e1761 127.0.0.1:7003
slots:0-5460 (5461 slots) master
1 additional replica(s)
[OK] All nodes agree about slots configuration.
 Check for open slots...
Check slots coverage...
[OK] All 16384 slots covered.
How many slots do you want to move (from 1 to 16384)?
它提示我们需要迁移多少slot到7006上，我们可以算一下：16384/4 = 4096，也就是说，
为了平衡分配起见，我们需要移动4096个槽点到7006上。 那输入4096:
How many slots do you want to move (from 1 to 16384)? 4096
What is the receiving node ID?
它又提示我们，接受的node ID是多少，7006的id 我们通过上面就可以看到是
efc3131fbdc6cf929720e0e0f7136cae85657481 :
What is the receiving node ID? efc3131fbdc6cf929720e0e0f7136cae85657481
Please enter all the source node IDs.
Type 'all' to use all the nodes as source nodes for the hash slots.
Type 'done' once you entered all the source nodes IDs.
Source node #1:
接着， redis-trib 会向你询问重新分片的源节点（source node）， 也即是， 要从哪个节
点中取出 4096 个哈希槽， 并将这些槽移动到7006节点上面。
如果我们不打算从特定的节点上取出指定数量的哈希槽， 那么可以向 redis-trib 输入 all ，
这样的话， 集群中的所有主节点都会成为源节点， redis-trib 将从各个源节点中各取出一
部分哈希槽， 凑够 4096 个， 然后移动到7006节点上： Source node #1:all 接下来就开
始迁移了，并且会询问你是否确认：
Moving slot 1359 from d2237fdcfbba672de766b913d1186cebcb6e1761
Moving slot 1360 from d2237fdcfbba672de766b913d1186cebcb6e1761
Moving slot 1361 from d2237fdcfbba672de766b913d1186cebcb6e1761
Moving slot 1362 from d2237fdcfbba672de766b913d1186cebcb6e1761
Moving slot 1363 from d2237fdcfbba672de766b913d1186cebcb6e1761
Moving slot 1364 from d2237fdcfbba672de766b913d1186cebcb6e1761
Do you want to proceed with the proposed reshard plan (yes/no)?
输入 yes 并使用按下回车之后， redis-trib 就会正式开始执行重新分片操作， 将指定的哈
希槽从源节点一个个地移动到7006节点上面。
迁移完毕之后，我们来检查下：
[root@web3 7006]# redis-trib.rb check 127.0.0.1:7000
Connecting to node 127.0.0.1:7000: OK
Connecting to node 127.0.0.1:7006: OK
Connecting to node 127.0.0.1:7004: OK
Connecting to node 127.0.0.1:7005: OK
Connecting to node 127.0.0.1:7003: OK
Connecting to node 127.0.0.1:7001: OK
Connecting to node 127.0.0.1:7002: OK
Performing Cluster Check (using node 127.0.0.1:7000)
S: 3707debcbe7be66d4a1968eaf3a5ffaf4308efa4 127.0.0.1:7000
slots: (0 slots) slave
replicates d2237fdcfbba672de766b913d1186cebcb6e1761
M: efc3131fbdc6cf929720e0e0f7136cae85657481 127.0.0.1:7006
slots:0-1364,5461-6826,10923-12287 (4096 slots) master
0 additional replica(s)
S: 4b4aef8b48c427a3c903518339d53b6447c58b93 127.0.0.1:7004
slots: (0 slots) slave
replicates cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c
S: 30858dbf483b61b9838d5c1f853a60beaa4e7afd 127.0.0.1:7005
slots: (0 slots) slave
replicates dfa0754c7854a874a6ebd2613b86140ad97701fc
M: d2237fdcfbba672de766b913d1186cebcb6e1761 127.0.0.1:7003
slots:1365-5460 (4096 slots) master
1 additional replica(s)
M: cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c 127.0.0.1:7001
slots:6827-10922 (4096 slots) master
1 additional replica(s)
M: dfa0754c7854a874a6ebd2613b86140ad97701fc 127.0.0.1:7002
slots:12288-16383 (4096 slots) master
1 additional replica(s)
[OK] All nodes agree about slots configuration.
 Check for open slots...
 Check slots coverage...
[OK] All 16384 slots covered.
我们着重看7006: 0-1364,5461-6826,10923-12287 (4096 slots) 这些原来在其他节点上
的slot呗迁移到了7006上。原来，它只是间隔的移动，并不是衔接的整体移动，我们看下
有数据了没？
[root@web3 7006]# redis-cli -c -p 7006
127.0.0.1:7006> keys *
1) "city"
2) "age"
3) "citylocate"
127.0.0.1:7006> get city
"shanghai"
非常赞，已经有数据了。
新建一个 7007从节点，作为7006的从节点 我们再新建一个节点7007，步骤类似，就先省
略了。建好后，启动起来，我们看如何把它加入到集群中的从节点中：
[root@web3 7007]# redis-trib.rb add-node --slave 127.0.0.1:7007 127.0.0.1:7000
add-node的时候加上--slave表示是加入到从节点中，但是这样加，是随机的。这里的命令
行完全像我们在添加一个新主服务器时使用的一样，所以我们没有指定要给哪个主服务器添
加副本。这种情况下，redis-trib 会将7007作为一个具有较少副本的随机的主服务器的副
本。
那么，它会作为谁的从节点，应该是7006，因为7006还没有从节点。我们运行下。
[root@web3 7007]# redis-trib.rb add-node --slave 127.0.0.1:7007 127.0.0.1:7000
...
...
[OK] All 16384 slots covered.
Automatically selected master 127.0.0.1:7006
Connecting to node 127.0.0.1:7007: OK
Send CLUSTER MEET to node 127.0.0.1:7007 to make it join the cluster.
Waiting for the cluster to join.
Configure node as replica of 127.0.0.1:7006.
[OK] New node added correctly.
上面提示说，自动选择了7006作为master节点。并且成功了。我们检查下：
[root@web3 7007]# redis-trib.rb check 127.0.0.1:7000
Connecting to node 127.0.0.1:7000: OK
Connecting to node 127.0.0.1:7006: OK
Connecting to node 127.0.0.1:7004: OK
Connecting to node 127.0.0.1:7005: OK
Connecting to node 127.0.0.1:7003: OK
Connecting to node 127.0.0.1:7001: OK
Connecting to node 127.0.0.1:7007: OK
Connecting to node 127.0.0.1:7002: OK
Performing Cluster Check (using node 127.0.0.1:7000)
S: 3707debcbe7be66d4a1968eaf3a5ffaf4308efa4 127.0.0.1:7000
slots: (0 slots) slave
replicates d2237fdcfbba672de766b913d1186cebcb6e1761
M: efc3131fbdc6cf929720e0e0f7136cae85657481 127.0.0.1:7006
slots:0-1364,5461-6826,10923-12287 (4096 slots) master
1 additional replica(s)
S: 4b4aef8b48c427a3c903518339d53b6447c58b93 127.0.0.1:7004
slots: (0 slots) slave
replicates cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c
S: 30858dbf483b61b9838d5c1f853a60beaa4e7afd 127.0.0.1:7005
slots: (0 slots) slave
replicates dfa0754c7854a874a6ebd2613b86140ad97701fc
M: d2237fdcfbba672de766b913d1186cebcb6e1761 127.0.0.1:7003
slots:1365-5460 (4096 slots) master
1 additional replica(s)
M: cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c 127.0.0.1:7001
slots:6827-10922 (4096 slots) master
1 additional replica(s)
S: 86d05e7c2b197dc182b5e71069e791d033cf899e 127.0.0.1:7007
slots: (0 slots) slave
replicates efc3131fbdc6cf929720e0e0f7136cae85657481
M: dfa0754c7854a874a6ebd2613b86140ad97701fc 127.0.0.1:7002
slots:12288-16383 (4096 slots) master
1 additional replica(s)
[OK] All nodes agree about slots configuration.
 Check for open slots...
 Check slots coverage...
[OK] All 16384 slots covered.
果然，7007加入到了7006的从节点当中。
如果想指定一个主节点行不行？当然可以。我们再建一个7008节点。
redis-trib.rb add-node --slave --master-id
efc3131fbdc6cf929720e0e0f7136cae85657481 127.0.0.1:7008 127.0.0.1:7000
--master-id表示指定的主节点node id。这里指定的是 7006 这个主节点。
 Configure node as replica of 127.0.0.1:7006.
[OK] New node added correctly.
提示我们已经作为7006的附属品，也就是加入到7006的从节点来了，照这么说，7006就有
2个从节点了，我们看一下：
redis-cli -c -p 7008 cluster nodes |grep
efc3131fbdc6cf929720e0e0f7136cae85657481
86d05e7c2b197dc182b5e71069e791d033cf899e 127.0.0.1:7007 slave
efc3131fbdc6cf929720e0e0f7136cae85657481 0 1445089507786 8 connected
efc3131fbdc6cf929720e0e0f7136cae85657481 127.0.0.1:7006 master - 0 1445089508289
8 connected 0-1364 5461-6826 10923-12287
44321e7d619410dc4e0a8745366610a0d06d2395 127.0.0.1:7008 myself,slave
efc3131fbdc6cf929720e0e0f7136cae85657481 0 0 0 connected
我们过滤了下看结果，果真，7007和7008是7006的从节点了。
我们再做一个实验，我把7006的杀掉，看7007和7008谁会变成主节点：
[root@web3 7008]# ps -ef|grep redis
root 11384 1 0 09:56 ? 00:00:16 redis-server *:7001 [cluster]
root 11388 1 0 09:56 ? 00:00:16 redis-server *:7002 [cluster]
root 11392 1 0 09:56 ? 00:00:16 redis-server *:7003 [cluster]
root 11396 1 0 09:56 ? 00:00:15 redis-server *:7004 [cluster]
root 11400 1 0 09:56 ? 00:00:15 redis-server *:7005 [cluster]
root 12100 1 0 11:01 ? 00:00:11 redis-server *:7000 [cluster]
root 12132 1 0 11:28 ? 00:00:11 redis-server *:7006 [cluster]
root 12202 1 0 13:14 ? 00:00:02 redis-server *:7007 [cluster]
root 12219 1 0 13:39 ? 00:00:00 redis-server *:7008 [cluster]
root 12239 8259 0 13:49 pts/0 00:00:00 grep redis
[root@web3 7008]# kill 12132
[root@web3 7008]# redis-cli -c -p 7008
127.0.0.1:7008> get ss5rtr
Redirected to slot [1188] located at 127.0.0.1:7007
"66"
127.0.0.1:7007> cluster nodes
efc3131fbdc6cf929720e0e0f7136cae85657481 127.0.0.1:7006 master,fail -
1445089780668 1445089779963 8 disconnected
d2237fdcfbba672de766b913d1186cebcb6e1761 127.0.0.1:7003 master - 0 1445089812195
7 connected 1365-5460
30858dbf483b61b9838d5c1f853a60beaa4e7afd 127.0.0.1:7005 slave
dfa0754c7854a874a6ebd2613b86140ad97701fc 0 1445089813710 3 connected
86d05e7c2b197dc182b5e71069e791d033cf899e 127.0.0.1:7007 myself,master - 0 0 10
connected 0-1364 5461-6826 10923-12287
cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c 127.0.0.1:7001 master - 0 1445089814214
2 connected 6827-10922
4b4aef8b48c427a3c903518339d53b6447c58b93 127.0.0.1:7004 slave
cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c 0 1445089812701 2 connected
44321e7d619410dc4e0a8745366610a0d06d2395 127.0.0.1:7008 slave
86d05e7c2b197dc182b5e71069e791d033cf899e 0 1445089814214 10 connected
3707debcbe7be66d4a1968eaf3a5ffaf4308efa4 127.0.0.1:7000 slave
d2237fdcfbba672de766b913d1186cebcb6e1761 0 1445089813204 7 connected
dfa0754c7854a874a6ebd2613b86140ad97701fc 127.0.0.1:7002 master - 0 1445089813204
3 connected 12288-16383
127.0.0.1:7007>
7007获得了成为主节点的机会，7008就变成了7007的从节点。 那么这个时候，重启7006
节点，那么他就会变成了一个7007的从节点了。
127.0.0.1:7008> cluster nodes
30858dbf483b61b9838d5c1f853a60beaa4e7afd 127.0.0.1:7005 slave
dfa0754c7854a874a6ebd2613b86140ad97701fc 0 1445089986148 3 connected
86d05e7c2b197dc182b5e71069e791d033cf899e 127.0.0.1:7007 master - 0
1445089986652 10 connected 0-1364 5461-6826 10923-12287
d2237fdcfbba672de766b913d1186cebcb6e1761 127.0.0.1:7003 master - 0
1445089986148 7 connected 1365-5460
cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c 127.0.0.1:7001 master - 0
1445089987155 2 connected 6827-10922
efc3131fbdc6cf929720e0e0f7136cae85657481 127.0.0.1:7006 slave
86d05e7c2b197dc182b5e71069e791d033cf899e 0 1445089985644 10 connected
44321e7d619410dc4e0a8745366610a0d06d2395 127.0.0.1:7008 myself,slave
86d05e7c2b197dc182b5e71069e791d033cf899e 0 0 0 connected
dfa0754c7854a874a6ebd2613b86140ad97701fc 127.0.0.1:7002 master - 0
1445089986652 3 connected 12288-16383
4b4aef8b48c427a3c903518339d53b6447c58b93 127.0.0.1:7004 slave
cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c 0 1445089987660 2 connected
3707debcbe7be66d4a1968eaf3a5ffaf4308efa4 127.0.0.1:7000 slave
d2237fdcfbba672de766b913d1186cebcb6e1761 0 1445089985644 7 connected
127.0.0.1:7008>
移除一个主节点 有加肯定有减，redis cluster同样支持移除节点功能，同样也是redistrib.rb的用法：
redis-trib del-node 127.0.0.1:7000 ``
和新加节点有点不同的是，移除需要节点的node-id。那我们尝试将7007这个主节点移
除：
[root@web3 7006]# redis-trib.rb del-node 127.0.0.1:7000
86d05e7c2b197dc182b5e71069e791d033cf899e
Removing node 86d05e7c2b197dc182b5e71069e791d033cf899e from cluster
127.0.0.1:7000
Connecting to node 127.0.0.1:7000: OK
Connecting to node 127.0.0.1:7006: OK
Connecting to node 127.0.0.1:7004: OK
Connecting to node 127.0.0.1:7001: OK
Connecting to node 127.0.0.1:7003: OK
Connecting to node 127.0.0.1:7007: OK
Connecting to node 127.0.0.1:7008: OK
Connecting to node 127.0.0.1:7005: OK
Connecting to node 127.0.0.1:7002: OK
[ERR] Node 127.0.0.1:7007 is not empty! Reshard data away and try again.
报错了，它提示我们说，由于7007里面已经有数据了，不能被移除，要先将它的数据转移
出去。也就是说得重新分片，用上面增加新节点后的分片方式一样，用我们再来一遍：
redis-trib.rb reshard 127.0.0.1:7000
由于中间太多内容，就省略不重要的，只简单说明下关键的几步：
M: 86d05e7c2b197dc182b5e71069e791d033cf899e 127.0.0.1:7007
slots:0-1364,5461-6826,10923-12287 (4096 slots) master
How many slots do you want to move (from 1 to 16384)?
提示，我们要分多少个槽点，由于7007上有4096个槽点，所以这里填写4096
How many slots do you want to move (from 1 to 16384)? 4096
What is the receiving node ID?
提示我们，需要移动到哪个id上，那就填7001的吧：
What is the receiving node ID? cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c
Please enter all the source node IDs.
Type 'all' to use all the nodes as source nodes for the hash slots.
Type 'done' once you entered all the source nodes IDs.
Source node #1:
这里就是关键了，它要我们从哪个节点去转移数据到7001，因为我们是要删除7007的，所
以，我们就得7007的id了
Source node #1:86d05e7c2b197dc182b5e71069e791d033cf899e
Source node #2:done
Do you want to proceed with the proposed reshard plan (yes/no)? yes
ok,这样就迁移好了。我们看看7007是否为空了：
[root@web3 7006]# redis-cli -c -p 7007
127.0.0.1:7007> keys *
(empty list or set)
127.0.0.1:7007> cluster nodes
86d05e7c2b197dc182b5e71069e791d033cf899e 127.0.0.1:7007 myself,master - 0 0 10
connected
果然为空了，好。现在再进行移除节点操作：
[root@web3 7006]# redis-trib.rb del-node 127.0.0.1:7000
86d05e7c2b197dc182b5e71069e791d033cf899e
Removing node 86d05e7c2b197dc182b5e71069e791d033cf899e from cluster
127.0.0.1:7000
Connecting to node 127.0.0.1:7000: OK
Connecting to node 127.0.0.1:7006: OK
Connecting to node 127.0.0.1:7004: OK
Connecting to node 127.0.0.1:7001: OK
Connecting to node 127.0.0.1:7003: OK
Connecting to node 127.0.0.1:7007: OK
Connecting to node 127.0.0.1:7008: OK
Connecting to node 127.0.0.1:7005: OK
Connecting to node 127.0.0.1:7002: OK
Sending CLUSTER FORGET messages to the cluster...
127.0.0.1:7006 as replica of 127.0.0.1:7001
127.0.0.1:7008 as replica of 127.0.0.1:7001
SHUTDOWN the node.
删除成功。
我们再检查一下：7007 已经移除，连不上了。
[root@web3 7006]# redis-trib.rb check 127.0.0.1:7007
Connecting to node 127.0.0.1:7007: [ERR] Sorry, can't connect to node
127.0.0.1:7007
[root@web3 7006]# redis-trib.rb check 127.0.0.1:7008
Connecting to node 127.0.0.1:7008: OK
Connecting to node 127.0.0.1:7005: OK
Connecting to node 127.0.0.1:7003: OK
Connecting to node 127.0.0.1:7001: OK
Connecting to node 127.0.0.1:7006: OK
Connecting to node 127.0.0.1:7002: OK
Connecting to node 127.0.0.1:7004: OK
Connecting to node 127.0.0.1:7000: OK
>>> Performing Cluster Check (using node 127.0.0.1:7008)
S: 44321e7d619410dc4e0a8745366610a0d06d2395 127.0.0.1:7008
slots: (0 slots) slave
replicates cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c
S: 30858dbf483b61b9838d5c1f853a60beaa4e7afd 127.0.0.1:7005
slots: (0 slots) slave
replicates dfa0754c7854a874a6ebd2613b86140ad97701fc
M: d2237fdcfbba672de766b913d1186cebcb6e1761 127.0.0.1:7003
slots:1365-5460 (4096 slots) master
1 additional replica(s)
M: cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c 127.0.0.1:7001
slots:0-1364,5461-12287 (8192 slots) master
3 additional replica(s)
S: efc3131fbdc6cf929720e0e0f7136cae85657481 127.0.0.1:7006
slots: (0 slots) slave
replicates cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c
M: dfa0754c7854a874a6ebd2613b86140ad97701fc 127.0.0.1:7002
slots:12288-16383 (4096 slots) master
1 additional replica(s)
S: 4b4aef8b48c427a3c903518339d53b6447c58b93 127.0.0.1:7004
slots: (0 slots) slave
replicates cb5c04b6160c3b7e18cad5d49d8e2987b27e0d6c
S: 3707debcbe7be66d4a1968eaf3a5ffaf4308efa4 127.0.0.1:7000
slots: (0 slots) slave
replicates d2237fdcfbba672de766b913d1186cebcb6e1761
[OK] All nodes agree about slots configuration.
 Check for open slots...
 Check slots coverage...
[OK] All 16384 slots covered.
7006和7008果然也成功加入到了7001集群。
移除一个从节点 移除一个从节点就简单的多了，因为不需要考虑数据的迁移，我们7008给
移除：
[root@web3 7006]# redis-trib.rb del-node 127.0.0.1:7008
44321e7d619410dc4e0a8745366610a0d06d2395
 Removing node 44321e7d619410dc4e0a8745366610a0d06d2395 from cluster
127.0.0.1:7005
Connecting to node 127.0.0.1:7005: OK
Connecting to node 127.0.0.1:7001: OK
Connecting to node 127.0.0.1:7002: OK
Connecting to node 127.0.0.1:7004: OK
Connecting to node 127.0.0.1:7000: OK
Connecting to node 127.0.0.1:7006: OK
Connecting to node 127.0.0.1:7008: OK
Connecting to node 127.0.0.1:7003: OK
 Sending CLUSTER FORGET messages to the cluster...
 SHUTDOWN the node.
[root@web3 7006]# redis-trib.rb check 127.0.0.1:7008
Connecting to node 127.0.0.1:7008: [ERR] Sorry, can't connect to node
127.0.0.1:7008
移除成功。

以上就是手动创建与自动创建redis集群方法的具体介绍，内容较为全面，而且我也相信有相当的一些工具可能是我们日常工作可能会见到或用到的。通过这篇文章，希望你能收获更多。