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Redis Cluster 自动化安装,扩容和缩容

[日期:2020-01-07] 来源:Linux公社  作者:醉落红尘 [字体: ]

Redis Cluster 自动化安装,扩容和缩容

之前写过一篇基于Python的redis集群自动化安装的实现,基于纯命令的集群实现还是相当繁琐的,因此官方提供了redis-trib.rb这个工具
虽然官方的的redis-trib.rb提供了集群创建、 检查、 修复、均衡等命令行工具,之所个人接受不了redis-trib.rb,原因在于redis-trib.rb无法自定义实现集群中节点的主从关系。
比如ABCDEF6个节点,在创建集群的过程中必然要明确指定哪些是主,哪些是从,主从对应关系,可惜通过redis-trib.rb无法自定义控制,参考如下截图。
更多的时候,是需要明确指明哪些机器作为主节点,哪些作为从节点,redis-trib.rb做不到自动控制集群中的哪些机器(实例)作为主,哪些机器(实例)作为从。
如果使用redis-trib.rb,还需要解决ruby的环境依赖,因此个人不太接受使用redis-trib.rb搭建集群。

引用《Redis开发与运维》里面的原话:
如果部署节点使用不同的IP地址, redis-trib.rb会尽可能保证主从节点不分配在同一机器下, 因此会重新排序节点列表顺序。
节点列表顺序用于确定主从角色, 先主节点之后是从节点。
这说明:使用redis-trib.rb是无法人为地完全控制主从节点的分配的。

后面redis 5.0版本的Redis-cli --cluster已经实现了集群的创建,无需依赖redis-trib.rb,包括ruby环境,redis 5.0版本Redis-cli --cluster本身已经实现了集群等相关功能
但是基于纯命令本身还是比较复杂的,尤其是在较为复杂的生产环境,通过手动方式来创建集群,扩容或者缩容,会存在一系列的手工操作,以及一些不安全因素。
所以,自动化的集群创建 ,扩容以及缩容是有必要的。

测试环境

这里基于Python3,以redis-cli --cluster命令为基础,实现redis自动化集群,自动化扩容,自动化缩容

测试环境以单机多实例为示例,一共8个节点,
1,自动化集群的创建,6各节点(10001~10006)创建为3主(10001~10002)3从(10004~10006)的集群
2,集群的自动化扩容,增加新节点10007为主节点,同时添加10008为10007节点的slave节点
3,集群的自动化缩容,与2相反,移除集群中的10007以及其slave的10008节点

 

Redis集群创建

集群的本质是执行两组命令,一个是将主节点加入到集群中,一个是依次对主节点添加slave节点。
但是期间会涉及到找到各个节点id的逻辑,因此手动实现的话,比较繁琐。
主要命令如下:

################# create cluster #################
redis-cli --cluster create 127.0.0.1:10001 127.0.0.1:10002 127.0.0.1:10003 -a ****** --cluster-yes
################# add slave nodes #################
redis-cli --cluster add-node 127.0.0.1:10004 127.0.0.1:10001 --cluster-slave --cluster-master-id 6164025849a8ff9297664fc835bc851af5004f61 -a ******
redis-cli --cluster add-node 127.0.0.1:10005 127.0.0.1:10002 --cluster-slave --cluster-master-id 64e634307bdc339b503574f5a77f1b156c021358 -a ******
redis-cli --cluster add-node 127.0.0.1:10006 127.0.0.1:10003 --cluster-slave --cluster-master-id 8b75325c59a7242344d0ebe5ee1e0068c66ffa2a -a ******

 

这里使用python创建的过程中打印出来redis-cli --cluster 命令的日志信息

[root@JD redis_install]# python3 create_redis_cluster.py
################# flush master/slave slots #################
################# create cluster #################
redis-cli --cluster create 127.0.0.1:10001 127.0.0.1:10002 127.0.0.1:10003   -a ****** --cluster-yes
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
>>> Performing hash slots allocation on 3 nodes...
Master[0] -> Slots 0 - 5460
Master[1] -> Slots 5461 - 10922
Master[2] -> Slots 10923 - 16383
M: 6164025849a8ff9297664fc835bc851af5004f61 127.0.0.1:10001
   slots:[0-5460] (5461 slots) master
M: 64e634307bdc339b503574f5a77f1b156c021358 127.0.0.1:10002
   slots:[5461-10922] (5462 slots) master
M: 8b75325c59a7242344d0ebe5ee1e0068c66ffa2a 127.0.0.1:10003
   slots:[10923-16383] (5461 slots) master
>>> 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 127.0.0.1:10001)
M: 6164025849a8ff9297664fc835bc851af5004f61 127.0.0.1:10001
   slots:[0-5460] (5461 slots) master
M: 8b75325c59a7242344d0ebe5ee1e0068c66ffa2a 127.0.0.1:10003
   slots:[10923-16383] (5461 slots) master
M: 64e634307bdc339b503574f5a77f1b156c021358 127.0.0.1:10002
   slots:[5461-10922] (5462 slots) master
[OK] All nodes agree about slots configuration.
>>> Check for open slots...
>>> Check slots coverage...
[OK] All 16384 slots covered.
0
################# add slave nodes #################
redis-cli --cluster add-node 127.0.0.1:10004 127.0.0.1:10001 --cluster-slave --cluster-master-id 6164025849a8ff9297664fc835bc851af5004f61 -a ******
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
>>> Adding node 127.0.0.1:10004 to cluster 127.0.0.1:10001
>>> Performing Cluster Check (using node 127.0.0.1:10001)
M: 6164025849a8ff9297664fc835bc851af5004f61 127.0.0.1:10001
   slots:[0-5460] (5461 slots) master
M: 8b75325c59a7242344d0ebe5ee1e0068c66ffa2a 127.0.0.1:10003
   slots:[10923-16383] (5461 slots) master
M: 64e634307bdc339b503574f5a77f1b156c021358 127.0.0.1:10002
   slots:[5461-10922] (5462 slots) master
[OK] All nodes agree about slots configuration.
>>> Check for open slots...
>>> Check slots coverage...
[OK] All 16384 slots covered.
>>> Send CLUSTER MEET to node 127.0.0.1:10004 to make it join the cluster.
Waiting for the cluster to join

>>> Configure node as replica of 127.0.0.1:10001.
[OK] New node added correctly.
0
redis-cli --cluster add-node 127.0.0.1:10005 127.0.0.1:10002 --cluster-slave --cluster-master-id 64e634307bdc339b503574f5a77f1b156c021358 -a ******
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
>>> Adding node 127.0.0.1:10005 to cluster 127.0.0.1:10002
>>> Performing Cluster Check (using node 127.0.0.1:10002)
M: 64e634307bdc339b503574f5a77f1b156c021358 127.0.0.1:10002
   slots:[5461-10922] (5462 slots) master
S: 026f0179631f50ca858d46c2b2829b3af71af2c8 127.0.0.1:10004
   slots: (0 slots) slave
   replicates 6164025849a8ff9297664fc835bc851af5004f61
M: 8b75325c59a7242344d0ebe5ee1e0068c66ffa2a 127.0.0.1:10003
   slots:[10923-16383] (5461 slots) master
M: 6164025849a8ff9297664fc835bc851af5004f61 127.0.0.1:10001
   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.
>>> Send CLUSTER MEET to node 127.0.0.1:10005 to make it join the cluster.
Waiting for the cluster to join

>>> Configure node as replica of 127.0.0.1:10002.
[OK] New node added correctly.
0
redis-cli --cluster add-node 127.0.0.1:10006 127.0.0.1:10003 --cluster-slave --cluster-master-id 8b75325c59a7242344d0ebe5ee1e0068c66ffa2a -a ******
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
>>> Adding node 127.0.0.1:10006 to cluster 127.0.0.1:10003
>>> Performing Cluster Check (using node 127.0.0.1:10003)
M: 8b75325c59a7242344d0ebe5ee1e0068c66ffa2a 127.0.0.1:10003
   slots:[10923-16383] (5461 slots) master
M: 64e634307bdc339b503574f5a77f1b156c021358 127.0.0.1:10002
   slots:[5461-10922] (5462 slots) master
   1 additional replica(s)
S: 23e1871c4e1dc1047ce567326e74a6194589146c 127.0.0.1:10005
   slots: (0 slots) slave
   replicates 64e634307bdc339b503574f5a77f1b156c021358
M: 6164025849a8ff9297664fc835bc851af5004f61 127.0.0.1:10001
   slots:[0-5460] (5461 slots) master
   1 additional replica(s)
S: 026f0179631f50ca858d46c2b2829b3af71af2c8 127.0.0.1:10004
   slots: (0 slots) slave
   replicates 6164025849a8ff9297664fc835bc851af5004f61
[OK] All nodes agree about slots configuration.
>>> Check for open slots...
>>> Check slots coverage...
[OK] All 16384 slots covered.
>>> Send CLUSTER MEET to node 127.0.0.1:10006 to make it join the cluster.
Waiting for the cluster to join

>>> Configure node as replica of 127.0.0.1:10003.
[OK] New node added correctly.
0
################# cluster nodes info: #################
8b75325c59a7242344d0ebe5ee1e0068c66ffa2a 127.0.0.1:10003@20003 myself,master - 0 1575947748000 53 connected 10923-16383
64e634307bdc339b503574f5a77f1b156c021358 127.0.0.1:10002@20002 master - 0 1575947748000 52 connected 5461-10922
23e1871c4e1dc1047ce567326e74a6194589146c 127.0.0.1:10005@20005 slave 64e634307bdc339b503574f5a77f1b156c021358 0 1575947746000 52 connected
6164025849a8ff9297664fc835bc851af5004f61 127.0.0.1:10001@20001 master - 0 1575947748103 51 connected 0-5460
026f0179631f50ca858d46c2b2829b3af71af2c8 127.0.0.1:10004@20004 slave 6164025849a8ff9297664fc835bc851af5004f61 0 1575947749000 51 connected
9f265545ebb799d2773cfc20c71705cff9d733ae 127.0.0.1:10006@20006 slave 8b75325c59a7242344d0ebe5ee1e0068c66ffa2a 0 1575947749105 53 connected

[root@JD redis_install]#

 

Redis集群扩容

redis扩容主要分为两步:
1,增加主节点,同时为主节点增加从节点。
2,重新分配slot到新增加的master节点上。

主要命令如下:

增加主节点到集群中
redis-cli --cluster add-node 127.0.0.1:10007 127.0.0.1:10001 -a ******
为增加的主节点添加从节点
redis-cli --cluster add-node 127.0.0.1:10008 127.0.0.1:10007 --cluster-slave --cluster-master-id 3645e00a8ec3a902bd6effb4fc20c56a00f2c982 -a ******

重新分片slot
############################ execute reshard #########################################
redis-cli -a redis@password --cluster reshard 127.0.0.1:10001 --cluster-from 6164025849a8ff9297664fc835bc851af5004f61 --cluster-to 3645e00a8ec3a902bd6effb4fc20c56a00f2c982 --cluster-slots 1365 --cluster-yes --cluster-timeout 50000 --cluster-pipeline 10000 --cluster-replace >/dev/null 2>&1
############################ execute reshard #########################################
redis-cli -a redis@password --cluster reshard 127.0.0.1:10002 --cluster-from 64e634307bdc339b503574f5a77f1b156c021358 --cluster-to 3645e00a8ec3a902bd6effb4fc20c56a00f2c982 --cluster-slots 1365 --cluster-yes --cluster-timeout 50000 --cluster-pipeline 10000 --cluster-replace >/dev/null 2>&1
############################ execute reshard #########################################
redis-cli -a redis@password --cluster reshard 127.0.0.1:10003 --cluster-from 8b75325c59a7242344d0ebe5ee1e0068c66ffa2a --cluster-to 3645e00a8ec3a902bd6effb4fc20c56a00f2c982 --cluster-slots 1365 --cluster-yes --cluster-timeout 50000 --cluster-pipeline 10000 --cluster-replace >/dev/null 2>&1

################# cluster nodes info: #################
026f0179631f50ca858d46c2b2829b3af71af2c8 127.0.0.1:10004@20004 slave 6164025849a8ff9297664fc835bc851af5004f61 0 1575960493000 64 connected
9f265545ebb799d2773cfc20c71705cff9d733ae 127.0.0.1:10006@20006 slave 8b75325c59a7242344d0ebe5ee1e0068c66ffa2a 0 1575960493849 66 connected
64e634307bdc339b503574f5a77f1b156c021358 127.0.0.1:10002@20002 master - 0 1575960494852 65 connected 6826-10922
23e1871c4e1dc1047ce567326e74a6194589146c 127.0.0.1:10005@20005 slave 64e634307bdc339b503574f5a77f1b156c021358 0 1575960492000 65 connected
4854375c501c3dbfb4e2d94d50e62a47520c4f12 127.0.0.1:10008@20008 slave 3645e00a8ec3a902bd6effb4fc20c56a00f2c982 0 1575960493000 67 connected
8b75325c59a7242344d0ebe5ee1e0068c66ffa2a 127.0.0.1:10003@20003 master - 0 1575960493000 66 connected 12288-16383
3645e00a8ec3a902bd6effb4fc20c56a00f2c982 127.0.0.1:10007@20007 myself,master - 0 1575960493000 67 connected 0-1364 5461-6825 10923-12287
6164025849a8ff9297664fc835bc851af5004f61 127.0.0.1:10001@20001 master - 0 1575960492848 64 connected 1365-5460
可见新加的节点成功重新分配了slot,集群扩容成功。

这里有几个需要注意的两个问题,如果是自动化安装的话:
1,add-node之后(不管是柱节点还是从节点),要sleep足够长的时间(这里是20秒),让集群中所有的节点都meet到新节点,否则会扩容失败
2,新节点的reshard之后要sleep足够长的时间(这里是20秒),否则继续reshard其他节点的slot会导致上一个reshared失败

 

整个过程如下

[root@JD redis_install]# python3 create_redis_cluster.py
#########################cleanup instance#################################
#########################add node into cluster#################################
 redis-cli --cluster add-node 127.0.0.1:10007 127.0.0.1:10001  -a redis@password
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
>>> Adding node 127.0.0.1:10007 to cluster 127.0.0.1:10001
>>> Performing Cluster Check (using node 127.0.0.1:10001)
M: 6164025849a8ff9297664fc835bc851af5004f61 127.0.0.1:10001
   slots:[0-5460] (5461 slots) master
   1 additional replica(s)
S: 9f265545ebb799d2773cfc20c71705cff9d733ae 127.0.0.1:10006
   slots: (0 slots) slave
   replicates 8b75325c59a7242344d0ebe5ee1e0068c66ffa2a
M: 8b75325c59a7242344d0ebe5ee1e0068c66ffa2a 127.0.0.1:10003
   slots:[10923-16383] (5461 slots) master
   1 additional replica(s)
S: 026f0179631f50ca858d46c2b2829b3af71af2c8 127.0.0.1:10004
   slots: (0 slots) slave
   replicates 6164025849a8ff9297664fc835bc851af5004f61
S: 23e1871c4e1dc1047ce567326e74a6194589146c 127.0.0.1:10005
   slots: (0 slots) slave
   replicates 64e634307bdc339b503574f5a77f1b156c021358
M: 64e634307bdc339b503574f5a77f1b156c021358 127.0.0.1:10002
   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 127.0.0.1:10007 to make it join the cluster.
[OK] New node added correctly.
0
 redis-cli --cluster add-node 127.0.0.1:10008 127.0.0.1:10007 --cluster-slave --cluster-master-id 3645e00a8ec3a902bd6effb4fc20c56a00f2c982 -a ******
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
>>> Adding node 127.0.0.1:10008 to cluster 127.0.0.1:10007
>>> Performing Cluster Check (using node 127.0.0.1:10007)
M: 3645e00a8ec3a902bd6effb4fc20c56a00f2c982 127.0.0.1:10007
   slots: (0 slots) master
S: 026f0179631f50ca858d46c2b2829b3af71af2c8 127.0.0.1:10004
   slots: (0 slots) slave
   replicates 6164025849a8ff9297664fc835bc851af5004f61
S: 9f265545ebb799d2773cfc20c71705cff9d733ae 127.0.0.1:10006
   slots: (0 slots) slave
   replicates 8b75325c59a7242344d0ebe5ee1e0068c66ffa2a
M: 64e634307bdc339b503574f5a77f1b156c021358 127.0.0.1:10002
   slots:[5461-10922] (5462 slots) master
   1 additional replica(s)
S: 23e1871c4e1dc1047ce567326e74a6194589146c 127.0.0.1:10005
   slots: (0 slots) slave
   replicates 64e634307bdc339b503574f5a77f1b156c021358
M: 8b75325c59a7242344d0ebe5ee1e0068c66ffa2a 127.0.0.1:10003
   slots:[10923-16383] (5461 slots) master
   1 additional replica(s)
M: 6164025849a8ff9297664fc835bc851af5004f61 127.0.0.1:10001
   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.
>>> Send CLUSTER MEET to node 127.0.0.1:10008 to make it join the cluster.
Waiting for the cluster to join

>>> Configure node as replica of 127.0.0.1:10007.
[OK] New node added correctly.
0
#########################reshard slots#################################
############################ execute reshard #########################################
redis-cli -a redis@password --cluster reshard 127.0.0.1:10001 --cluster-from 6164025849a8ff9297664fc835bc851af5004f61 --cluster-to 3645e00a8ec3a902bd6effb4fc20c56a00f2c982 --cluster-slots 1365 --cluster-yes --cluster-timeout 50000 --cluster-pipeline 10000   --cluster-replace  >/dev/null 2>&1
############################ execute reshard #########################################
redis-cli -a redis@password --cluster reshard 127.0.0.1:10002 --cluster-from 64e634307bdc339b503574f5a77f1b156c021358 --cluster-to 3645e00a8ec3a902bd6effb4fc20c56a00f2c982 --cluster-slots 1365 --cluster-yes --cluster-timeout 50000 --cluster-pipeline 10000   --cluster-replace  >/dev/null 2>&1
############################ execute reshard #########################################
redis-cli -a redis@password --cluster reshard 127.0.0.1:10003 --cluster-from 8b75325c59a7242344d0ebe5ee1e0068c66ffa2a --cluster-to 3645e00a8ec3a902bd6effb4fc20c56a00f2c982 --cluster-slots 1365 --cluster-yes --cluster-timeout 50000 --cluster-pipeline 10000   --cluster-replace  >/dev/null 2>&1
################# cluster nodes info: #################
026f0179631f50ca858d46c2b2829b3af71af2c8 127.0.0.1:10004@20004 slave 6164025849a8ff9297664fc835bc851af5004f61 0 1575960493000 64 connected
9f265545ebb799d2773cfc20c71705cff9d733ae 127.0.0.1:10006@20006 slave 8b75325c59a7242344d0ebe5ee1e0068c66ffa2a 0 1575960493849 66 connected
64e634307bdc339b503574f5a77f1b156c021358 127.0.0.1:10002@20002 master - 0 1575960494852 65 connected 6826-10922
23e1871c4e1dc1047ce567326e74a6194589146c 127.0.0.1:10005@20005 slave 64e634307bdc339b503574f5a77f1b156c021358 0 1575960492000 65 connected
4854375c501c3dbfb4e2d94d50e62a47520c4f12 127.0.0.1:10008@20008 slave 3645e00a8ec3a902bd6effb4fc20c56a00f2c982 0 1575960493000 67 connected
8b75325c59a7242344d0ebe5ee1e0068c66ffa2a 127.0.0.1:10003@20003 master - 0 1575960493000 66 connected 12288-16383
3645e00a8ec3a902bd6effb4fc20c56a00f2c982 127.0.0.1:10007@20007 myself,master - 0 1575960493000 67 connected 0-1364 5461-6825 10923-12287
6164025849a8ff9297664fc835bc851af5004f61 127.0.0.1:10001@20001 master - 0 1575960492848 64 connected 1365-5460

[root@JD redis_install]#

 

Redis集群缩容

缩容按道理是扩容的反向操作.
从这个命令就可以看出来:del-node host:port node_id #删除给定的一个节点,成功后关闭该节点服务。
缩容就缩容了,从集群中移除掉(cluster forget nodeid)某个主节点就行了,为什么还要关闭?因此本文不会采用redis-cli --cluster del-node的方式缩容,而是通过普通命令行来缩容。

这里的自定义缩容实质上分两步
1,将移除的主节点的slot分配回集群中其他节点,这里测试四个主节点缩容为三个主节点,实际上执行命令如下。
2,集群中的节点依次执行cluster forget master_node_id(slave_node_id)

############################ execute reshard #########################################
redis-cli -a ****** --cluster reshard 127.0.0.1:10001 --cluster-from 3645e00a8ec3a902bd6effb4fc20c56a00f2c982 --cluster-to 6164025849a8ff9297664fc835bc851af5004f61 --cluster-slots 1365 --cluster-yes --cluster-timeout 50000 --cluster-pipeline 10000 --cluster-replace >/dev/null 2>&1
############################ execute reshard #########################################
redis-cli -a ****** --cluster reshard 127.0.0.1:10002 --cluster-from 3645e00a8ec3a902bd6effb4fc20c56a00f2c982 --cluster-to 64e634307bdc339b503574f5a77f1b156c021358 --cluster-slots 1365 --cluster-yes --cluster-timeout 50000 --cluster-pipeline 10000 --cluster-replace >/dev/null 2>&1
############################ execute reshard #########################################
redis-cli -a ****** --cluster reshard 127.0.0.1:10003 --cluster-from 3645e00a8ec3a902bd6effb4fc20c56a00f2c982 --cluster-to 8b75325c59a7242344d0ebe5ee1e0068c66ffa2a --cluster-slots 1365 --cluster-yes --cluster-timeout 50000 --cluster-pipeline 10000 --cluster-replace >/dev/null 2>&1

{'host': '127.0.0.1', 'port': 10001, 'password': '******'}--->cluster forget 3645e00a8ec3a902bd6effb4fc20c56a00f2c982
{'host': '127.0.0.1', 'port': 10001, 'password': '******'}--->cluster forget 4854375c501c3dbfb4e2d94d50e62a47520c4f12
{'host': '127.0.0.1', 'port': 10002, 'password': '******'}--->cluster forget 3645e00a8ec3a902bd6effb4fc20c56a00f2c982
{'host': '127.0.0.1', 'port': 10002, 'password': '******'}--->cluster forget 4854375c501c3dbfb4e2d94d50e62a47520c4f12
{'host': '127.0.0.1', 'port': 10003, 'password': '******'}--->cluster forget 3645e00a8ec3a902bd6effb4fc20c56a00f2c982
{'host': '127.0.0.1', 'port': 10003, 'password': '******'}--->cluster forget 4854375c501c3dbfb4e2d94d50e62a47520c4f12
{'host': '127.0.0.1', 'port': 10004, 'password': '******'}--->cluster forget 3645e00a8ec3a902bd6effb4fc20c56a00f2c982
{'host': '127.0.0.1', 'port': 10004, 'password': '******'}--->cluster forget 4854375c501c3dbfb4e2d94d50e62a47520c4f12
{'host': '127.0.0.1', 'port': 10005, 'password': '******'}--->cluster forget 3645e00a8ec3a902bd6effb4fc20c56a00f2c982
{'host': '127.0.0.1', 'port': 10005, 'password': '******'}--->cluster forget 4854375c501c3dbfb4e2d94d50e62a47520c4f12
{'host': '127.0.0.1', 'port': 10006, 'password': '******'}--->cluster forget 3645e00a8ec3a902bd6effb4fc20c56a00f2c982
{'host': '127.0.0.1', 'port': 10006, 'password': '******'}--->cluster forget 4854375c501c3dbfb4e2d94d50e62a47520c4f12

 

完整代码如下

[root@JD redis_install]# python3 create_redis_cluster.py
############################ execute reshard #########################################
redis-cli -a ****** --cluster reshard 127.0.0.1:10001 --cluster-from 3645e00a8ec3a902bd6effb4fc20c56a00f2c982 --cluster-to 6164025849a8ff9297664fc835bc851af5004f61 --cluster-slots 1365 --cluster-yes --cluster-timeout 50000 --cluster-pipeline 10000 --cluster-replace >/dev/null 2>&1
############################ execute reshard #########################################
redis-cli -a ****** --cluster reshard 127.0.0.1:10002 --cluster-from 3645e00a8ec3a902bd6effb4fc20c56a00f2c982 --cluster-to 64e634307bdc339b503574f5a77f1b156c021358 --cluster-slots 1365 --cluster-yes --cluster-timeout 50000 --cluster-pipeline 10000 --cluster-replace >/dev/null 2>&1
############################ execute reshard #########################################
redis-cli -a ****** --cluster reshard 127.0.0.1:10003 --cluster-from 3645e00a8ec3a902bd6effb4fc20c56a00f2c982 --cluster-to 8b75325c59a7242344d0ebe5ee1e0068c66ffa2a --cluster-slots 1365 --cluster-yes --cluster-timeout 50000 --cluster-pipeline 10000 --cluster-replace >/dev/null 2>&1
{'host': '127.0.0.1', 'port': 10001, 'password': '******'}--->cluster forget 3645e00a8ec3a902bd6effb4fc20c56a00f2c982
{'host': '127.0.0.1', 'port': 10001, 'password': '******'}--->cluster forget 4854375c501c3dbfb4e2d94d50e62a47520c4f12
{'host': '127.0.0.1', 'port': 10002, 'password': '******'}--->cluster forget 3645e00a8ec3a902bd6effb4fc20c56a00f2c982
{'host': '127.0.0.1', 'port': 10002, 'password': '******'}--->cluster forget 4854375c501c3dbfb4e2d94d50e62a47520c4f12
{'host': '127.0.0.1', 'port': 10003, 'password': '******'}--->cluster forget 3645e00a8ec3a902bd6effb4fc20c56a00f2c982
{'host': '127.0.0.1', 'port': 10003, 'password': '******'}--->cluster forget 4854375c501c3dbfb4e2d94d50e62a47520c4f12
{'host': '127.0.0.1', 'port': 10004, 'password': '******'}--->cluster forget 3645e00a8ec3a902bd6effb4fc20c56a00f2c982
{'host': '127.0.0.1', 'port': 10004, 'password': '******'}--->cluster forget 4854375c501c3dbfb4e2d94d50e62a47520c4f12
{'host': '127.0.0.1', 'port': 10005, 'password': '******'}--->cluster forget 3645e00a8ec3a902bd6effb4fc20c56a00f2c982
{'host': '127.0.0.1', 'port': 10005, 'password': '******'}--->cluster forget 4854375c501c3dbfb4e2d94d50e62a47520c4f12
{'host': '127.0.0.1', 'port': 10006, 'password': '******'}--->cluster forget 3645e00a8ec3a902bd6effb4fc20c56a00f2c982
{'host': '127.0.0.1', 'port': 10006, 'password': '******'}--->cluster forget 4854375c501c3dbfb4e2d94d50e62a47520c4f12
################# cluster nodes info: #################
23e1871c4e1dc1047ce567326e74a6194589146c 127.0.0.1:10005@20005 slave 64e634307bdc339b503574f5a77f1b156c021358 0 1575968426000 76 connected
026f0179631f50ca858d46c2b2829b3af71af2c8 127.0.0.1:10004@20004 slave 6164025849a8ff9297664fc835bc851af5004f61 0 1575968422619 75 connected
6164025849a8ff9297664fc835bc851af5004f61 127.0.0.1:10001@20001 myself,master - 0 1575968426000 75 connected 0-5460
9f265545ebb799d2773cfc20c71705cff9d733ae 127.0.0.1:10006@20006 slave 8b75325c59a7242344d0ebe5ee1e0068c66ffa2a 0 1575968425000 77 connected
8b75325c59a7242344d0ebe5ee1e0068c66ffa2a 127.0.0.1:10003@20003 master - 0 1575968427626 77 connected 10923-16383
64e634307bdc339b503574f5a77f1b156c021358 127.0.0.1:10002@20002 master - 0 1575968426000 76 connected 5461-10922

[root@JD redis_install]#

其实到这里并没有结束,这里要求缩容之后集群中的所有节点都要成功地执行cluster forget master_node_id(和slave_node_id)
否则其他节点仍然有10007节点的心跳信息,超过1分钟之后,仍旧会将已经踢出集群的10007节点(以及从节点10008)会被添加回来
这就一开始就遇到一个奇葩问题,因为没有在缩容后的集群的slave节点上执行cluster forget,被移除的节点,会不断地被添加回来……。
参考这里:http://www.redis.cn/commands/cluster-forget.html

 

 

 

完整的代码实现如下

import os
import time
import redis
from time import ctime,sleep


def create_redis_cluster(list_master_node,list_slave_node):
    print('################# flush master/slave slots #################')
    for node in list_master_node:
        currenrt_conn = redis.StrictRedis(host=node["host"], port=node["port"], password=node["password"], decode_responses=True)
        currenrt_conn.execute_command('flushall')
        currenrt_conn.execute_command('cluster reset')

    for node in list_slave_node:
        currenrt_conn = redis.StrictRedis(host=node["host"], port=node["port"], password=node["password"], decode_responses=True)
        #currenrt_conn.execute_command('flushall')
        currenrt_conn.execute_command('cluster reset')

    print('################# create cluster #################')
    master_nodes = ''
    for node in list_master_node:
        master_nodes = master_nodes + node["host"] + ':' + str(node["port"]) + ' '
    command = "redis-cli --cluster create {0}  -a ****** --cluster-yes".format(master_nodes)
    print(command)
    msg = os.system(command)
    print(msg)
    time.sleep(5)

    print('################# add slave nodes #################')
    counter = 0
    for node in list_master_node:
        currenrt_conn = redis.StrictRedis(host=node["host"], port=node["port"], password=node["password"], decode_responses=True)
        current_master_node = node["host"] + ':' + str(node["port"])
        current_slave_node = list_slave_node[counter]["host"] + ':' + str(list_slave_node[counter]["port"])
        myid = currenrt_conn.cluster('myid')
        #slave 节点在前,master节点在后
        command = "redis-cli --cluster add-node {0} {1} --cluster-slave --cluster-master-id {2} -a ****** ". format(current_slave_node,current_master_node,myid)
        print(command)
        msg = os.system(command)
        counter = counter + 1
        print(msg)
    # show cluster nodes info
    time.sleep(10)
    print("################# cluster nodes info: #################")
    cluster_nodes = currenrt_conn.execute_command('cluster nodes')
    print(cluster_nodes)

# 返回扩容后,原始节点中,每个主节点需要迁出的slot数量
def get_migrated_slot(list_master_node,n):
    migrated_slot_count = int(16384/len(list_master_node)) - int(16384/(len(list_master_node)+n))
    return migrated_slot_count

def redis_cluster_expansion(list_master_node,dict_master_node,dict_slave_node):
    new_master_node =  dict_master_node["host"] + ':' + str(dict_master_node["port"])
    new_slave_node = dict_slave_node["host"] + ':' + str(dict_slave_node["port"])

    print("#########################cleanup instance#################################")
    new_master_conn = redis.StrictRedis(host=dict_master_node["host"], port=dict_master_node["port"], password=dict_master_node["password"], decode_responses=True)
    new_master_conn.execute_command('flushall')
    new_master_conn.execute_command('cluster reset')
    new_master_id = new_master_conn.cluster('myid')

    new_slave_conn = redis.StrictRedis(host=dict_slave_node["host"], port=dict_slave_node["port"], password=dict_slave_node["password"], decode_responses=True)
    new_slave_conn.execute_command('cluster reset')
    new_slave_id = new_slave_conn.cluster('myid')
    #new_slave_conn.execute_command('slaveof no one')

    # 判断新增的节点是否归属于当前集群,
    # 如果已经归属于当前集群且不占用slot,则先踢出当前集群 cluster forget nodeid,或者终止,给出告警,总之,怎么开心怎么来
    # 登录集群中的任何一个节点
    cluster_node_conn = redis.StrictRedis(host=list_master_node[0]["host"], port=list_master_node[0]["port"], password=list_master_node[0]["password"],decode_responses=True)
    dict_node_info = cluster_node_conn.cluster('nodes')
    '''dict_node_info format example :
    {
    '127.0.0.1:10008@20008': {'node_id': '1d10c3ce3b9b7f956a26122980827fe6ce623d22', 'flags': 'master', 'master_id': '-','last_ping_sent': '0', 'last_pong_rcvd': '1575599442000', 'epoch': '8', 'slots': [], 'connected': True}, 
    '127.0.0.1:10002@20002': {'node_id': '64e634307bdc339b503574f5a77f1b156c021358', 'flags': 'master', 'master_id': '-', 'last_ping_sent': '0', 'last_pong_rcvd': '1575599442000', 'epoch': '7', 'slots': [['5461', '10922']], 'connected': True}, 
    '127.0.0.1:10001@20001': {'node_id': '6164025849a8ff9297664fc835bc851af5004f61', 'flags': 'myself,master', 'master_id': '-', 'last_ping_sent': '0', 'last_pong_rcvd': '1575599438000', 'epoch': '6', 'slots': [['0', '5460']], 'connected': True}, 
    '127.0.0.1:10007@20007': {'node_id': '307f589ec7b1eb7bd65c680527afef1e30ce2303', 'flags': 'master', 'master_id': '-', 'last_ping_sent': '0', 'last_pong_rcvd': '1575599443599', 'epoch': '5', 'slots': [], 'connected': True}, 
    '127.0.0.1:10005@20005': {'node_id': '23e1871c4e1dc1047ce567326e74a6194589146c', 'flags': 'slave', 'master_id': '64e634307bdc339b503574f5a77f1b156c021358', 'last_ping_sent': '0', 'last_pong_rcvd': '1575599441000', 'epoch': '7', 'slots': [], 'connected': True}, 
    '127.0.0.1:10004@20004': {'node_id': '026f0179631f50ca858d46c2b2829b3af71af2c8', 'flags': 'slave', 'master_id': '6164025849a8ff9297664fc835bc851af5004f61', 'last_ping_sent': '0', 'last_pong_rcvd': '1575599440000', 'epoch': '6', 'slots': [], 'connected': True}, 
    '127.0.0.1:10006@20006': {'node_id': '9f265545ebb799d2773cfc20c71705cff9d733ae', 'flags': 'slave', 'master_id': '8b75325c59a7242344d0ebe5ee1e0068c66ffa2a', 'last_ping_sent': '0', 'last_pong_rcvd': '1575599442000', 'epoch': '8', 'slots': [], 'connected': True}, 
    '127.0.0.1:10003@20003': {'node_id': '8b75325c59a7242344d0ebe5ee1e0068c66ffa2a', 'flags': 'master', 'master_id': '-', 'last_ping_sent': '0', 'last_pong_rcvd': '1575599442599', 'epoch': '8', 'slots': [['10923', '16383']], 'connected': True}
    }
    '''
    dict_master_node_in_cluster = 0
    dict_slave_node_in_cluster = 0

    for key_node in dict_node_info:
        if new_master_node in key_node:
            dict_master_node_in_cluster = 1
            if len(dict_node_info[key_node]['slots']) > 0:
                print('error: ' +new_master_node + ' already existing in cluster and alloted slots,execute break......')
                return
        if new_slave_node in key_node:
            dict_slave_node_in_cluster = 1
            if len(dict_node_info[key_node]['slots']) > 0:
                print('error: ' +new_slave_node + ' already existing in cluster and alloted slots,execute break......')
                return

    if dict_master_node_in_cluster == 1:
        for master_node in list_master_node:
            key_node_conn = redis.StrictRedis(host=master_node["host"], port=master_node["port"],password=master_node["password"], decode_responses=True)
            print('waring: ' + new_master_node + ' already existing in cluster,cluster forget it......')
            forget_command = 'cluster forget {0}'.format(new_master_id)
            key_node_conn.execute_command(forget_command)
    if dict_slave_node_in_cluster == 1:
        for master_node in list_master_node:
            key_node_conn = redis.StrictRedis(host=master_node["host"], port=master_node["port"],password=master_node["password"], decode_responses=True)
            print('waring: ' + new_slave_node + ' already existing in cluster,forget it......')
            forget_command = 'cluster forget {0}'.format(new_slave_id)
            key_node_conn.execute_command(forget_command)

    print("#########################add node into cluster#################################")
    try:
        cluster_node = list_master_node[0]["host"] + ':' + str(list_master_node[0]["port"])
        # 1,待加入节点在前,第二个节点为集群中的任意一个节点
        add_node_command = " redis-cli --cluster add-node {0} {1}  -a ****** ".format(new_master_node,cluster_node)
        print(add_node_command)
        print(os.system(add_node_command))
        time.sleep(20)
        # slave 节点在前,master节点在后
        add_node_command = " redis-cli --cluster add-node {0} {1} --cluster-slave --cluster-master-id {2} -a ****** ". format(new_slave_node,new_master_node,new_master_id)
        print(add_node_command)
        print(os.system(add_node_command))
        time.sleep(20)
    except Exception as e:
        print('add new node error,the reason is:')
        print(e)

    print("#########################reshard slots#################################")
    migrated_slot_count = get_migrated_slot(list_master_node,1)
    for node in list_master_node:
        current_master_conn = redis.StrictRedis(host=node["host"], port=node["port"], password=node["password"], decode_responses=True)
        current_master_node = node["host"] + ':' + str(node["port"])
        current_master_node_id = current_master_conn.cluster('myid')
        '''
        example:3节点-->扩容4节点,每个迁移1365
        '''
        try:
            command = r'''redis-cli -a ****** --cluster reshard {0} --cluster-from {1} --cluster-to {2} --cluster-slots {3} --cluster-yes --cluster-timeout 50000 --cluster-pipeline 10000   --cluster-replace  >/dev/null 2>&1 '''. format(current_master_node,current_master_node_id,new_master_id,migrated_slot_count)
            print('############################ execute reshard #########################################')
            print(command)
            msg = os.system(command)
            time.sleep(20)
        except Exception as e:
            print('reshard slots error,the reason is:')
            print(e)

    print("################# cluster nodes info: #################")
    cluster_nodes = new_master_conn.execute_command('cluster nodes')
    print(cluster_nodes)


def redis_cluster_shrinkage(list_master_node,list_slave_node,dict_master_node,dict_slave_node):
    # 判断新增的节点是否归属于当前集群,
    # 如果不归属当前集群,则退出
    cluster_node_conn = redis.StrictRedis(host=list_master_node[0]["host"], port=list_master_node[0]["port"], password=list_master_node[0]["password"],decode_responses=True)
    dict_node_info = cluster_node_conn.cluster('nodes')

    removed_master_node = dict_master_node["host"] + ':' + str(dict_master_node["port"])+'@'+str(dict_master_node["port"]+10000)
    removed_slave_node = dict_slave_node["host"] + ':' + str(dict_slave_node["port"])+'@'+str(dict_slave_node["port"]+10000)

    if not removed_master_node in dict_node_info.keys():
        print('Error:'+ str(removed_master_node) +' not in cluster,exiting')
        return
    if not removed_slave_node in dict_node_info.keys():
        print('Error:' + str(removed_slave_node) + ' not in cluster,exiting')
        return

    removed_master_conn = redis.StrictRedis(host=dict_master_node["host"], port=dict_master_node["port"], password=dict_master_node["password"], decode_responses=True)
    removed_master_id = removed_master_conn.cluster('myid')
    removed_slave_conn = redis.StrictRedis(host=dict_slave_node["host"], port=dict_slave_node["port"], password=dict_slave_node["password"], decode_responses=True)
    removed_slave_id = removed_slave_conn.cluster('myid')

    for node in list_master_node:
        current_master_conn = redis.StrictRedis(host=node["host"], port=node["port"], password=node["password"], decode_responses=True)
        current_master_node = node["host"] + ':' + str(node["port"])
        current_master_node_id = current_master_conn.cluster('myid')
        '''
        4节点-->缩容3节点,平均将slot归还到三个master节点
        '''
        try:
            command = r'''redis-cli -a ****** --cluster reshard {0} --cluster-from {1} --cluster-to {2} --cluster-slots 1365 --cluster-yes --cluster-timeout 50000 --cluster-pipeline 10000   --cluster-replace  >/dev/null 2>&1 '''.\
                format(current_master_node, removed_master_id, current_master_node_id)
            print('############################ execute reshard #########################################')
            print(command)
            msg = os.system(command)
            time.sleep(10)
        except Exception as e:
            print('reshard slots error,the reason is:')
            print(e)

    removed_master_conn.execute_command('cluster reset')
    removed_slave_conn.execute_command('cluster reset')

    for master_node in list_master_node:
        master_node_conn =  redis.StrictRedis(host=master_node["host"], port=master_node["port"],password=master_node["password"], decode_responses=True)
        foget_master_command = 'cluster forget {0}'.format(removed_master_id)
        foget_slave_command = 'cluster forget {0}'.format(removed_slave_id)
        print(str(master_node)+ '--->' + foget_master_command)
        print(str(master_node)+ '--->' + foget_slave_command)
        master_node_conn.execute_command(foget_master_command)
        master_node_conn.execute_command(foget_slave_command)

    for slave_node in list_slave_node:
        slave_node_conn = redis.StrictRedis(host=slave_node["host"], port=slave_node["port"], password=slave_node["password"], decode_responses=True)
        foget_master_command = 'cluster forget {0}'.format(removed_master_id)
        foget_slave_command = 'cluster forget {0}'.format(removed_slave_id)
        print(str(slave_node)+ '--->' +foget_master_command)
        print(str(slave_node)+ '--->' +foget_slave_command)
        slave_node_conn.execute_command(foget_master_command)
        slave_node_conn.execute_command(foget_slave_command)

    print("################# cluster nodes info: #################")
    cluster_nodes = cluster_node_conn.execute_command('cluster nodes')
    print(cluster_nodes)


if __name__ == '__main__':
    # master
    node_1 = {'host': '127.0.0.1', 'port': 10001, 'password': '******'}
    node_2 = {'host': '127.0.0.1', 'port': 10002, 'password': '******'}
    node_3 = {'host': '127.0.0.1', 'port': 10003, 'password': '******'}
    # slave
    node_4 = {'host': '127.0.0.1', 'port': 10004, 'password': '******'}
    node_5 = {'host': '127.0.0.1', 'port': 10005, 'password': '******'}
    node_6 = {'host': '127.0.0.1', 'port': 10006, 'password': '******'}
    # 主从节点个数必须相同
    list_master_node = [node_1, node_2, node_3]
    list_slave_node = [node_4, node_5, node_6]
    
    # 自动化集群创建
    #create_redis_cluster(list_master_node,list_slave_node)

    # 自动化扩容
    node_1 = {'host': '127.0.0.1', 'port': 10007, 'password': '******'}
    node_2 = {'host': '127.0.0.1', 'port': 10008, 'password': '******'}
    redis_cluster_expansion(list_master_node,node_1,node_2)
    
    # 自动化缩容,
    #redis_cluster_shrinkage(list_master_node,list_slave_node,node_1,node_2)
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