redis节点管理-节点的移除

原文：http://blog.sina.com.cn/s/blog_53b45c4d0102wg13.html

节点的移除

和节点添加一样，移除节点也有移除主节点，从节点。

1、移除主节点

移除节点使用redis-trib的del-node命令，

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redis-trib del-node 127.0.0.1:7002 ${node-id}

127.0.0.1:7002位集群节点，node-id为要删除的主节点。和添加节点不同，移除节点node-id是必需的，测试删除7001主节点：

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[root@localhost redis-cluster]# ./redis-trib.rb del-node 127.0.0.1:7001 dd19221c404fb2fc4da37229de56bab755c76f2b
>>> Removing node dd19221c404fb2fc4da37229de56bab755c76f2b from cluster 127.0.0.1:7002
[ERR] Node 127.0.0.1:7001 is not empty! Reshard data away and try again.
[root@localhost redis-cluster]#

redis cluster提示7001已经有数据了，不能够被删除，需要将他的数据转移出去，也就是和新增主节点一样需重新分片。

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[root@localhost redis-cluster]# ./redis-trib.rb reshard 127.0.0.1:7002

执行以后会提示我们移除的大小，因为7001占用了4096个槽点

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>>> Check for open slots...
>>> Check slots coverage...
[OK] All 16384 slots covered.
How many slots do you want to move (from 1 to 16384)?

输入4096

提示移动的node id，填写7009的node id。(这里好像有误，应该填移动到的node id)

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How many slots do you want to move (from 1 to 16384)? 4096
What is the receiving node ID? (接收的nodeid)

需要移动到全部主节点上还是单个主节点（这里好像有误，需要移动的的节点ID，可移动单个节点，也可移动多节点的槽位）

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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:

将4096个槽点移动到7009上，填写7001的node id ：dd19221c404fb2fc4da37229de56bab755c76f2b

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Source node #1:dd19221c404fb2fc4da37229de56bab755c76f2b
Source node #2:done
Do you want to proceed with the proposed reshard plan (yes/no)? yes

确认之后会一个一个将7001的卡槽移到到7009上。

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[root@localhost redis-cluster]# ./redis-trib.rb check 127.0.0.1:7009
>>> Performing Cluster Check (using node 127.0.0.1:7009)
M: 1f51443ede952b98724fea2a12f61fe710ab6cb1 127.0.0.1:7009
slots:0-6826,10923-12287 (8192 slots) master
3 additional replica(s)
S: ee3efb90e5ac0725f15238a64fc60a18a71205d7 127.0.0.1:7007
slots: (0 slots) slave
replicates 1f51443ede952b98724fea2a12f61fe710ab6cb1
S: 50ce1ea59106b4c2c6bc502593a6a7a7dabf5041 127.0.0.1:7004
slots: (0 slots) slave
replicates 1f51443ede952b98724fea2a12f61fe710ab6cb1
M: f9886c71e98a53270f7fda961e1c5f730382d48f 127.0.0.1:7003
slots:12288-16383 (4096 slots) master
1 additional replica(s)
M: dd19221c404fb2fc4da37229de56bab755c76f2b 127.0.0.1:7001
slots: (0 slots) master
0 additional replica(s)
S: 2ab1b061c36f30ae35604e9a171ae3afdc3c87e5 127.0.0.1:7008
slots: (0 slots) slave
replicates 1f51443ede952b98724fea2a12f61fe710ab6cb1
S: 1f07d76585bfab35f91ec711ac53ab4bc00f2d3a 127.0.0.1:7002
slots: (0 slots) slave
replicates a5db243087d8bd423b9285fa8513eddee9bb59a6
S: 8bb3ede48319b46d0015440a91ab277da9353c8b 127.0.0.1:7006
slots: (0 slots) slave
replicates f9886c71e98a53270f7fda961e1c5f730382d48f
M: a5db243087d8bd423b9285fa8513eddee9bb59a6 127.0.0.1:7005
slots:6827-10922 (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.
[root@localhost redis-cluster]#

可以看到7001有0个卡槽，而7009有8192个卡槽。

在执行移除操作

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[root@localhost redis-cluster]# ./redis-trib.rb del-node 127.0.0.1:7002 dd19221c404fb2fc4da37229de56bab755c76f2b
>>> Removing node dd19221c404fb2fc4da37229de56bab755c76f2b from cluster 127.0.0.1:7002
>>> Sending CLUSTER FORGET messages to the cluster...
>>> SHUTDOWN the node.
[root@localhost redis-cluster]#

已经删除了7001节点。

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[root@localhost redis-cluster]# ./redis-trib.rb check 127.0.0.1:7001
[ERR] Sorry, can't connect to node 127.0.0.1:7001
[root@localhost redis-cluster]# ./redis-trib.rb check 127.0.0.1:7009
>>> Performing Cluster Check (using node 127.0.0.1:7009)
M: 1f51443ede952b98724fea2a12f61fe710ab6cb1 127.0.0.1:7009
slots:0-6826,10923-12287 (8192 slots) master
3 additional replica(s)
S: ee3efb90e5ac0725f15238a64fc60a18a71205d7 127.0.0.1:7007
slots: (0 slots) slave
replicates 1f51443ede952b98724fea2a12f61fe710ab6cb1
S: 50ce1ea59106b4c2c6bc502593a6a7a7dabf5041 127.0.0.1:7004
slots: (0 slots) slave
replicates 1f51443ede952b98724fea2a12f61fe710ab6cb1
M: f9886c71e98a53270f7fda961e1c5f730382d48f 127.0.0.1:7003
slots:12288-16383 (4096 slots) master
1 additional replica(s)
S: 2ab1b061c36f30ae35604e9a171ae3afdc3c87e5 127.0.0.1:7008
slots: (0 slots) slave
replicates 1f51443ede952b98724fea2a12f61fe710ab6cb1
S: 1f07d76585bfab35f91ec711ac53ab4bc00f2d3a 127.0.0.1:7002
slots: (0 slots) slave
replicates a5db243087d8bd423b9285fa8513eddee9bb59a6
S: 8bb3ede48319b46d0015440a91ab277da9353c8b 127.0.0.1:7006
slots: (0 slots) slave
replicates f9886c71e98a53270f7fda961e1c5f730382d48f
M: a5db243087d8bd423b9285fa8513eddee9bb59a6 127.0.0.1:7005
slots:6827-10922 (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.
[root@localhost redis-cluster]#

可以看到7001已经连接不了；而7001的从节点7004自动分配到了7009主节点中，7009现在3个从节点。

2、移除从节点

比如删除7009的7008节点：

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[root@localhost redis-cluster]# ./redis-trib.rb del-node 127.0.0.1:7009 2ab1b061c36f30ae35604e9a171ae3afdc3c87e5
>>> Removing node 2ab1b061c36f30ae35604e9a171ae3afdc3c87e5 from cluster 127.0.0.1:7009
>>> Sending CLUSTER FORGET messages to the cluster...
>>> SHUTDOWN the node.
[root@localhost redis-cluster]# ./redis-trib.rb check 127.0.0.1:7008
[ERR] Sorry, can't connect to node 127.0.0.1:7008
[root@localhost redis-cluster]#

删除从节点比较方便，现在redis-cluster中有3个主节点，4个从节点，如下：

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[root@localhost redis-cluster]# ./redis-trib.rb check 127.0.0.1:7009
>>> Performing Cluster Check (using node 127.0.0.1:7009)
M: 1f51443ede952b98724fea2a12f61fe710ab6cb1 127.0.0.1:7009
slots:0-6826,10923-12287 (8192 slots) master
2 additional replica(s)
S: ee3efb90e5ac0725f15238a64fc60a18a71205d7 127.0.0.1:7007
slots: (0 slots) slave
replicates 1f51443ede952b98724fea2a12f61fe710ab6cb1
S: 50ce1ea59106b4c2c6bc502593a6a7a7dabf5041 127.0.0.1:7004
slots: (0 slots) slave
replicates 1f51443ede952b98724fea2a12f61fe710ab6cb1
M: f9886c71e98a53270f7fda961e1c5f730382d48f 127.0.0.1:7003
slots:12288-16383 (4096 slots) master
1 additional replica(s)
S: 1f07d76585bfab35f91ec711ac53ab4bc00f2d3a 127.0.0.1:7002
slots: (0 slots) slave
replicates a5db243087d8bd423b9285fa8513eddee9bb59a6
S: 8bb3ede48319b46d0015440a91ab277da9353c8b 127.0.0.1:7006
slots: (0 slots) slave
replicates f9886c71e98a53270f7fda961e1c5f730382d48f
M: a5db243087d8bd423b9285fa8513eddee9bb59a6 127.0.0.1:7005
slots:6827-10922 (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.
[root@localhost redis-cluster]#