Redis cluster 使用 slots 来分配集群中的资源，因此官方提供了热迁移 slots 的方案，以便于迁移 redis cluster 节点中的信息。此方案不仅可以使用于节点迁移，也可以根据资源的不同，配置不同的 slots 数量。
集群原环境：
主机 IP ： 192.168.170.101
集群节点端口： 10001-10006
集群当前主备关系：
迁移需求：现在有节点 redis007, 需要将 redis002 替换掉
迁移步骤：
首先验证环境当前的配置：
由上可以看出节点信息如下：
10001M<-10004S slots=5461
10002M<-10005S slots=5462
10003M<-10006S slots=5461
现在来插入 10W 条数据
from rediscluster import StrictRedisCluster
redis_nodes = [{ "host" : "192.168.170.101" , "port" : "10001" } ,
{ "host" : "192.168.170.101" , "port" : "10002" } ,
{ "host" : "192.168.170.101" , "port" : "10003" } ,
{ "host" : "192.168.170.101" , "port" : "10004" } ,
{ "host" : "192.168.170.101" , "port" : "10005" } ,
{ "host" : "192.168.170.101" , "port" : "10006" }
]
redis_conn = StrictRedisCluster ( startup_nodes = redis_nodes, decode_responses = True )
for key in range ( 0 , 100000 ) :
print key
value = key
key = 'zhang%s' % key
redis_conn.set ( key, value )
启动 redis007 ，并将 redis007 加入集群环境：
./redis-server redis007.conf
[root@lab001 redis]# redis-trib.rb add-node 192.168.170.101:10007 192.168.170.101:10001>>> Adding node 192.168.170.101:10007 to cluster 192.168.170.101:10001
>>> Performing Cluster Check (using node 192.168.170.101:10001)
M: b30fdabd07a4bef611c160828965b91a1cdd462a 192.168.170.101:10001
slots:0-5460 (5461 slots) master
1 additional replica(s)
S: 74805544792cc22f09af941fa117b2974c9c0abf 192.168.170.101:10005
slots: (0 slots) slave
replicates 6036af6afc6567b74ce2fecc734a2d3908d561d1
M: 9c6a98926b23585e2eeb49ae17cc77521041d3ed 192.168.170.101:10003
slots:10923-16383 (5461 slots) master
1 additional replica(s)
S: 57a2e7313b952b38e32d6a1030d4812ea4decb5f 192.168.170.101:10006
slots: (0 slots) slave
replicates 9c6a98926b23585e2eeb49ae17cc77521041d3ed
S: 58b7b25501fdba04aef9b8cb47edef89092f10a7 192.168.170.101:10004
slots: (0 slots) slave
replicates b30fdabd07a4bef611c160828965b91a1cdd462a
M: 6036af6afc6567b74ce2fecc734a2d3908d561d1 192.168.170.101:10002
slots:5461-10922 (5462 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.>>> Send CLUSTER MEET to node 192.168.170.101:10007 to make it join the cluster.
[OK] New node added correctly.查看当前节点状态信息
[root@lab001 redis]# redis-trib.rb check 192.168.170.101:10001>>> Performing Cluster Check (using node 192.168.170.101:10001)
M: b30fdabd07a4bef611c160828965b91a1cdd462a 192.168.170.101:10001
slots:0-5460 (5461 slots) master
1 additional replica(s)
M: 7c1a0acf84b2cf08876036b07518fb8f2ea9b8f8 192.168.170.101:10007
slots: (0 slots) master
0 additional replica(s)
S: 74805544792cc22f09af941fa117b2974c9c0abf 192.168.170.101:10005
slots: (0 slots) slave
replicates 6036af6afc6567b74ce2fecc734a2d3908d561d1
M: 9c6a98926b23585e2eeb49ae17cc77521041d3ed 192.168.170.101:10003
slots:10923-16383 (5461 slots) master
1 additional replica(s)
S: 57a2e7313b952b38e32d6a1030d4812ea4decb5f 192.168.170.101:10006
slots: (0 slots) slave
replicates 9c6a98926b23585e2eeb49ae17cc77521041d3ed
S: 58b7b25501fdba04aef9b8cb47edef89092f10a7 192.168.170.101:10004
slots: (0 slots) slave
replicates b30fdabd07a4bef611c160828965b91a1cdd462a
M: 6036af6afc6567b74ce2fecc734a2d3908d561d1 192.168.170.101:10002
slots:5461-10922 (5462 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.由上可以发现， redis007 添加到节点当中，但当前未分配任何 slots ，这一步把 redis002 的 slots 完全迁移到 redis007
由于过程较长，这里不再输出全部过程
[root@lab001 redis]# redis-trib.rb reshard --from 6036af6afc6567b74ce2fecc734a2d3908d561d1 --to 7c1a0acf84b2cf08876036b07518fb8f2ea9b8f8 --slots 5462 --yes 192.168.170.101:10001………………
Moving slot 10911 from 192.168.170.101:10002 to 192.168.170.101:10007: .....
Moving slot 10912 from 192.168.170.101:10002 to 192.168.170.101:10007: ..........
Moving slot 10913 from 192.168.170.101:10002 to 192.168.170.101:10007: ......
Moving slot 10914 from 192.168.170.101:10002 to 192.168.170.101:10007: .......
Moving slot 10915 from 192.168.170.101:10002 to 192.168.170.101:10007: .....
Moving slot 10916 from 192.168.170.101:10002 to 192.168.170.101:10007: .....
Moving slot 10917 from 192.168.170.101:10002 to 192.168.170.101:10007: ...
Moving slot 10918 from 192.168.170.101:10002 to 192.168.170.101:10007: ........
Moving slot 10919 from 192.168.170.101:10002 to 192.168.170.101:10007: .....
Moving slot 10920 from 192.168.170.101:10002 to 192.168.170.101:10007: .......
M