Redis热迁移实战总结

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:

  1. 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

  1. 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)

  1. 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.

  1. 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.

  1. 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redis002slots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: .......

Moving slot 10921 from 192.168.170.101:10002 to 192.168.170.101:10007: ..

Moving slot 10922 from 192.168.170.101:10002 to 192.168.170.101:10007: ..........

  1. 再次查看当前节点信息

[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:5461-10922 (5462 slots) master

  1 additional replica(s)

S: 74805544792cc22f09af941fa117b2974c9c0abf 192.168.170.101:10005

  slots: (0 slots) slave

  replicates 7c1a0acf84b2cf08876036b07518fb8f2ea9b8f8

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: (0 slots) master

  0 additional replica(s)

[OK] All nodes agree about slots configuration.

>>> Check for open slots...

>>> Check slots coverage...

[OK] All 16384 slots covered.

由此可以发现,redis002的所有slots迁移到redis007完毕,并且redis005自动将主从关系从002转移到了007

  1. 最后来验证下数据的完整性

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):

    #value = key

    key = 'zhang%s' % key

    #redis_conn.set(key, value)

    print redis_conn.get(key)

 

执行完毕,数据较验完成,数据完成完整迁移

  1. 最后,将redis002从集群中移除

[root@lab001 redis]# redis-trib.rb del-node 192.168.170.101:10001 6036af6afc6567b74ce2fecc734a2d3908d561d1

>>> Removing node 6036af6afc6567b74ce2fecc734a2d3908d561d1 from cluster 192.168.170.101:10001

>>> Sending CLUSTER FORGET messages to the cluster...

>>> SHUTDOWN the node.

[2]  Done                    ./redis001/bin/redis-server redis00$i/redis00$i.conf

  1. 再次查看集群状态

[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:5461-10922 (5462 slots) master

  1 additional replica(s)

S: 74805544792cc22f09af941fa117b2974c9c0abf 192.168.170.101:10005

  slots: (0 slots) slave

  replicates 7c1a0acf84b2cf08876036b07518fb8f2ea9b8f8

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

[OK] All nodes agree about slots configuration.

>>> Check for open slots...

>>> Check slots coverage...

[OK] All 16384 slots covered.

[root@lab001 redis]# redis-trib.rb info 192.168.170.101:10001

192.168.170.101:10001 (b30fdabd...) -> 33357 keys | 5461 slots | 1 slaves.

192.168.170.101:10007 (7c1a0acf...) -> 33283 keys | 5462 slots | 1 slaves.

192.168.170.101:10003 (9c6a9892...) -> 33360 keys | 5461 slots | 1 slaves.

[OK] 100000 keys in 3 masters.

6.10 keys per slot on average.

总结:

1. slots迁移在日常工作中,通常用于节点迁移、扩展,也可以根据服务器本身的压力将slots迁移至性能较优的服务器

2. slots迁移过程当中,不影响数据的读写,这点已经做过实际的测试。

3. 迁移过程当中,应用配置应当至少包含一个集群master节点信息,否则有可能会造成数据访问异常的情况。迁移完成并配置同步更新至最新后,方可删除旧的空slots节点。

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