1、简述redis集群的实现原理
在哨兵sentinel机制中，可以解决redis的高可用问题，即当master故障后可以自动将slave提升为master，从而可以保证redis服务的正常运行，但是还是无法解决redis单机写入的瓶颈问题，即单机redis写入性能受限于单机的内存大小、并发数量、网卡速率等因素。
为了解决单机redis性能的瓶颈，提高redis的性能，可以使用分布式集群的解决方案。
在早期的Redis分布式集群部署方案：
- 客户端分区：由客户端程序决定key写分配和写入的redis node，但是需要客户端自己实现写入分配、高可用管理和故障转移等；
- 代理方案：基于三方软件实现redis proxy，客户端先连接之代理层，由代理层实现key的写入分配，对客户端来说是有比较简单，但是对于集群管节点增减相对比较麻烦，而且代理本身也是单点和性能瓶颈。
redis在3.0的版本后就推出了无中心架构的redis cluster机制，在无中心的redis集群当中，其每个节点保存当前节点数据和整个集群状态，每个节点都可以和其他节点连接。
Redis Cluster特点如下：
- 所有Redis节点使用(PING机制)互联
- 集群中某个节点的是否失效，是由整个集群中超过半数的节点监测都失效，才能算真正的失效
- 客户端不需要proxy即可直接连接redis，应用程序中需要配置有全部的redis服务器IP
- redis cluster把所有的redis node平均映射到 0-16383个槽位(slot)上，读写需要到指定的redis node上进行操作，因此有多少个redis node相当于redis并发扩展了多少倍，每个redis node承担16384/N个槽位
- Redis cluster预先分配16384个(slot)槽位，当需要在redis集群中写入一个key -value的时候，会使用CRC16(key) mod 16384之后的值，决定将key写入值哪一个槽位从而决定写入哪一个Redis节点上，从而有效解决单机瓶颈。
2、基于redis5的redis cluster部署
2.1、创建redis cluster集群的环境准备
- 每个redis节点采用的redis版本要相同、相同的密码、硬件配置也最好是相同
- 所有redis服务器必须没有任何数据
- 这里我是准备了六台主机：
| IP地址 | redis版本 | 主机名 |
|---|---|---|
| 10.1.2.208 | redis-6.2.7 | node1.stars.org |
| 10.1.2.209 | redis-6.2.7 | node2.stars.org |
| 10.1.2.210 | redis-6.2.7 | node3.stars.org |
| 10.1.2.213 | redis-6.2.7 | node4.stars.org |
| 10.1.2.215 | redis-6.2.7 | node5.stars.org |
| 10.1.2.217 | redis-6.2.7 | node6.stars.org |
2.2、启用redis cluster配置
这里安装redis是使用的脚本一键安装的，脚本放在文章的最后了。
- 每个节点修改redis配置，必须开启cluster功能的参数
#手动修改配置文件需要修改的项 bind 0.0.0.0 masterauth wm521314 #建议配置，否则后期的master和slave主从复制无法成功，还需再配置 requirepass wm521314 cluster-enabled yes #取消此行注释,必须开启集群，开启后redis 进程会有cluster标识 cluster-config-file nodes-6379.conf #取消此行注释,此为集群状态文件,记录主从关系及slot范围信息,由redis cluster集群自动创建和维护 cluster-require-full-coverage no #默认值为yes,设为no可以防止一个节点不可用导致整个cluster不可能
#在这里我就使用sed修改配置文件了
root@node1:~# sed -i.bak -e '/masterauth/a masterauth wm521314' -e '/# cluster-enabled yes/a cluster-enabled yes' -e '/# cluster-config-file nodes-6379.conf/a cluster-config-file nodes-6379.conf' -e '/cluster-require-full-coverage yes/c cluster-require-full-coverage no' /apps/redis/etc/redis.conf
root@node1:~# systemctl restart redis
- 验证所有节点的Redis服务状态：
```bash
#开启了16379的cluster的端口,实际的端口=redis port + 10000
root@node1:~# ss -tnl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 0.0.0.0:34374 0.0.0.0:*
LISTEN 0 128 0.0.0.0:13450 0.0.0.0:*
LISTEN 0 511 0.0.0.0:6379 0.0.0.0:*
LISTEN 0 64 0.0.0.0:32654 0.0.0.0:*
LISTEN 0 128 0.0.0.0:111 0.0.0.0:*
LISTEN 0 128 0.0.0.0:51538 0.0.0.0:*
LISTEN 0 128 127.0.0.53%lo:53 0.0.0.0:*
LISTEN 0 128 0.0.0.0:22 0.0.0.0:*
LISTEN 0 128 127.0.0.1:6010 0.0.0.0:*
LISTEN 0 511 0.0.0.0:16379 0.0.0.0:*
LISTEN 0 64 0.0.0.0:2049 0.0.0.0:*
LISTEN 0 64 [::]:10214 [::]:*
LISTEN 0 128 [::]:111 [::]:*
LISTEN 0 128 [::]:16208 [::]:*
LISTEN 0 128 [::]:22288 [::]:*
LISTEN 0 128 [::]:22 [::]:*
LISTEN 0 128 [::]:57046 [::]:*
LISTEN 0 128 [::1]:6010 [::]:*
LISTEN 0 64 [::]:2049 [::]:*
#查看redis进程状态
root@node1:~# ps aux | grep redis
redis 22669 0.2 0.1 63004 5692 ? Ssl 12:13 0:00 /apps/redis/bin/redis-server 0.0.0.0:6379 [cluster]
root 22677 0.0 0.0 14860 1088 pts/0 S+ 12:15 0:00 grep --color=auto redis2.3、创建集群
#命令redis-cli的选项 --cluster-replicas 1 表示每个master对应一个slave节点
root@node1:~# redis-cli -a wm521314 --cluster create 10.1.2.208:6379 10.1.2.209:6379 10.1.2.210:6379 10.1.2.213:6379 10.1.2.215:6379 10.1.2.217:6379 --cluster-replicas 1
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
>>> Performing hash slots allocation on 6 nodes...
Master[0] -> Slots 0 - 5460
Master[1] -> Slots 5461 - 10922
Master[2] -> Slots 10923 - 16383
Adding replica 10.1.2.215:6379 to 10.1.2.208:6379
Adding replica 10.1.2.217:6379 to 10.1.2.209:6379
Adding replica 10.1.2.213:6379 to 10.1.2.210:6379
M: 2d04605711615ba0acbf2a098c9c79c59b23f408 10.1.2.208:6379 #带M指的是master
slots:[0-5460] (5461 slots) master #当前master的槽位起始和结束位
M: 1e79791c833562821282d9aec31f4d116fc5e1c7 10.1.2.209:6379
slots:[5461-10922] (5462 slots) master
M: bbc82d4f8a1c6c062a88711a32d1ac08dc59a647 10.1.2.210:6379
slots:[10923-16383] (5461 slots) master
S: 285c027937cf19ed100efda1b5116c4bae04e50a 10.1.2.213:6379 #带S的slave
replicates bbc82d4f8a1c6c062a88711a32d1ac08dc59a647
S: 8f463789ccd8638709df9611270b2c0cd83984d5 10.1.2.215:6379
replicates 2d04605711615ba0acbf2a098c9c79c59b23f408
S: d1112ea7d3bed02b6b4e1d89aa19fd3a38568ffd 10.1.2.217:6379
replicates 1e79791c833562821282d9aec31f4d116fc5e1c7
Can I set the above configuration? (type 'yes' to accept): yes #输入yes自动创建集群
>>> 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 10.1.2.208:6379)
M: 2d04605711615ba0acbf2a098c9c79c59b23f408 10.1.2.208:6379
slots:[0-5460] (5461 slots) master #已经分配的槽位
1 additional replica(s) #分配了一个slave
S: 8f463789ccd8638709df9611270b2c0cd83984d5 10.1.2.215:6379
slots: (0 slots) slave #slave没有分配槽位
replicates 2d04605711615ba0acbf2a098c9c79c59b23f408 #对应的master的10.1.2.208的ID
S: d1112ea7d3bed02b6b4e1d89aa19fd3a38568ffd 10.1.2.217:6379
slots: (0 slots) slave
replicates 1e79791c833562821282d9aec31f4d116fc5e1c7 #对应的master的10.1.2.209的ID
S: 285c027937cf19ed100efda1b5116c4bae04e50a 10.1.2.213:6379
slots: (0 slots) slave
replicates bbc82d4f8a1c6c062a88711a32d1ac08dc59a647 #对应的master的10.1.2.210的ID
M: 1e79791c833562821282d9aec31f4d116fc5e1c7 10.1.2.209:6379
slots:[5461-10922] (5462 slots) master
1 additional replica(s)
M: bbc82d4f8a1c6c062a88711a32d1ac08dc59a647 10.1.2.210:6379
slots:[10923-16383] (5461 slots) master
1 additional replica(s)
[OK] All nodes agree about slots configuration. #所有节点槽位分配完成
>>> Check for open slots... #检查打开的槽位
>>> Check slots coverage... #检查插槽覆盖范围
[OK] All 16384 slots covered. #所有槽位(16384个)分配完成
#从上面的结果，可以得到3组主从
master:10.1.2.208---slave:10.1.2.215
master:10.1.2.209---slave:10.1.2.217
master:10.1.2.210---slave:10.1.2.2132.4、查看主从状态
#node1节点
root@node1:~# redis-cli -a wm521314 -c INFO replication
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
# Replication
role:master
connected_slaves:1
slave0:ip=10.1.2.215,port=6379,state=online,offset=630,lag=0
master_failover_state:no-failover
master_replid:055976e21e5d2123da62fcc65b2d1ee5ac523545
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:630
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:630
#node2节点
root@node2:~# redis-cli -a wm521314 -c INFO replication
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
# Replication
role:master
connected_slaves:1
slave0:ip=10.1.2.217,port=6379,state=online,offset=658,lag=0
master_failover_state:no-failover
master_replid:7ca9dafd1456cdb45fb7e25c7147bd1e89d36f01
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:658
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:658
#node3节点
root@node3:~# redis-cli -a wm521314 -c INFO replication
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
# Replication
role:master
connected_slaves:1
slave0:ip=10.1.2.213,port=6379,state=online,offset=672,lag=1
master_failover_state:no-failover
master_replid:4d10bc7e1a4ae847d62a198d0b9eef1729a01af8
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:686
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:686
#node4节点
root@node4:~# redis-cli -a wm521314 -c INFO replication
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
# Replication
role:slave
master_host:10.1.2.210
master_port:6379
master_link_status:up
master_last_io_seconds_ago:1
master_sync_in_progress:0
slave_read_repl_offset:798
slave_repl_offset:798
slave_priority:100
slave_read_only:1
replica_announced:1
connected_slaves:0
master_failover_state:no-failover
master_replid:4d10bc7e1a4ae847d62a198d0b9eef1729a01af8
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:798
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:798
#node5节点
root@node5:~# redis-cli -a wm521314 -c INFO replication
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
# Replication
role:slave
master_host:10.1.2.208
master_port:6379
master_link_status:up
master_last_io_seconds_ago:6
master_sync_in_progress:0
slave_read_repl_offset:812
slave_repl_offset:812
slave_priority:100
slave_read_only:1
replica_announced:1
connected_slaves:0
master_failover_state:no-failover
master_replid:055976e21e5d2123da62fcc65b2d1ee5ac523545
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:812
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:812
#node6节点
root@node6:~# redis-cli -a wm521314 -c INFO replication
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
# Replication
role:slave
master_host:10.1.2.209
master_port:6379
master_link_status:up
master_last_io_seconds_ago:7
master_sync_in_progress:0
slave_read_repl_offset:840
slave_repl_offset:840
slave_priority:100
slave_read_only:1
replica_announced:1
connected_slaves:0
master_failover_state:no-failover
master_replid:7ca9dafd1456cdb45fb7e25c7147bd1e89d36f01
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:840
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:840
#查看集群中几个节点的对应关系
root@node1:~# redis-cli -a wm521314 cluster nodes
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
8f463789ccd8638709df9611270b2c0cd83984d5 10.1.2.215:6379@16379 slave 2d04605711615ba0acbf2a098c9c79c59b23f408 0 1653569184000 1 connected
d1112ea7d3bed02b6b4e1d89aa19fd3a38568ffd 10.1.2.217:6379@16379 slave 1e79791c833562821282d9aec31f4d116fc5e1c7 0 1653569183634 2 connected
2d04605711615ba0acbf2a098c9c79c59b23f408 10.1.2.208:6379@16379 myself,master - 0 1653569183000 1 connected 0-5460
285c027937cf19ed100efda1b5116c4bae04e50a 10.1.2.213:6379@16379 slave bbc82d4f8a1c6c062a88711a32d1ac08dc59a647 0 1653569185000 3 connected
1e79791c833562821282d9aec31f4d116fc5e1c7 10.1.2.209:6379@16379 master - 0 1653569185643 2 connected 5461-10922
bbc82d4f8a1c6c062a88711a32d1ac08dc59a647 10.1.2.210:6379@16379 master - 0 1653569184638 3 connected 10923-163832.5、验证集群的状态
root@node1:~# redis-cli -a wm521314 cluster info
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
cluster_state:ok
cluster_slots_assigned:16384
cluster_slots_ok:16384
cluster_slots_pfail:0
cluster_slots_fail:0
cluster_known_nodes:6 #集群中的节点数
cluster_size:3 #集群数量
cluster_current_epoch:6
cluster_my_epoch:1
cluster_stats_messages_ping_sent:779
cluster_stats_messages_pong_sent:786
cluster_stats_messages_sent:1565
cluster_stats_messages_ping_received:781
cluster_stats_messages_pong_received:779
cluster_stats_messages_meet_received:5
cluster_stats_messages_received:1565
#查看某个节点的集群状态
root@node1:~# redis-cli -a wm521314 --cluster info 10.1.2.209:6379
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
10.1.2.209:6379 (1e79791c...) -> 0 keys | 5462 slots | 1 slaves.
10.1.2.210:6379 (bbc82d4f...) -> 0 keys | 5461 slots | 1 slaves.
10.1.2.208:6379 (2d046057...) -> 0 keys | 5461 slots | 1 slaves.
[OK] 0 keys in 3 masters.
0.00 keys per slot on average.
#查看集群的状态文件
root@node1:~# cat /apps/redis/data/nodes-6379.conf
8f463789ccd8638709df9611270b2c0cd83984d5 10.1.2.215:6379@16379 slave 2d04605711615ba0acbf2a098c9c79c59b23f408 0 1653568467000 1 connected
d1112ea7d3bed02b6b4e1d89aa19fd3a38568ffd 10.1.2.217:6379@16379 slave 1e79791c833562821282d9aec31f4d116fc5e1c7 0 1653568468000 2 connected
2d04605711615ba0acbf2a098c9c79c59b23f408 10.1.2.208:6379@16379 myself,master - 0 1653568462000 1 connected 0-5460
285c027937cf19ed100efda1b5116c4bae04e50a 10.1.2.213:6379@16379 slave bbc82d4f8a1c6c062a88711a32d1ac08dc59a647 0 1653568468937 3 connected
1e79791c833562821282d9aec31f4d116fc5e1c7 10.1.2.209:6379@16379 master - 0 1653568467931 2 connected 5461-10922
bbc82d4f8a1c6c062a88711a32d1ac08dc59a647 10.1.2.210:6379@16379 master - 0 1653568467000 3 connected 10923-16383
vars currentEpoch 6 lastVoteEpoch 02.6、使用Python脚本实现Redis Cluster集群的写入
#这里需要下载一些相关的包，我这使用的是ubuntu的1804版本系统，系统里面带了python3但是少了一些包需要自己安装
root@node1:~# apt install python3-pip
root@node1:~# pip3 install redis-py-cluster
root@node1:~# vim redis_cluster_test.py
#!/usr/bin/env python3
from rediscluster import RedisCluster
if __name__ == '__main__':
startup_nodes = [
{"host":"10.0.0.8", "port":6379},
{"host":"10.0.0.18", "port":6379},
{"host":"10.0.0.28", "port":6379},
{"host":"10.0.0.38", "port":6379},
{"host":"10.0.0.48", "port":6379},
{"host":"10.0.0.58", "port":6379}]
try:
redis_conn= RedisCluster(startup_nodes=startup_nodes,password='123456', decode_responses=True)
except Exception as e:
print(e)
for i in range(0, 10000):
redis_conn.set('key'+str(i),'value'+str(i))
print('key'+str(i)+':',redis_conn.get('key'+str(i)))
root@node1:~# chmod +x redis_cluster_test.py
root@node1:~# ./redis_cluster_test.py
........
key9995: value9995
key9996: value9996
key9997: value9997
key9998: value9998
key9999: value9999
#验证数据是否写入
root@node1:~# redis-cli -a wm521314 -h 10.1.2.208 dbsize
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
(integer) 3331
root@node1:~# redis-cli -a wm521314 -h 10.1.2.209 dbsize
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
(integer) 3340
root@node1:~# redis-cli -a wm521314 -h 10.1.2.210 dbsize
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
(integer) 3329
root@node1:~# redis-cli -a wm521314 -h 10.1.2.209 get key10
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
"value10"2.7、模拟master故障，对应的slave节点自动提升为新master
#假设node3节点出问题，需要相应的数秒故障转移时间，先查看一下node3节点没出问题的时候信息
root@node3:~# redis-cli -a wm521314 -c INFO replication
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
# Replication
role:master
connected_slaves:1
slave0:ip=10.1.2.213,port=6379,state=online,offset=138842,lag=1
master_failover_state:no-failover
master_replid:4d10bc7e1a4ae847d62a198d0b9eef1729a01af8
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:138842
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:138842
#向redis服务发出一个shutdown的指令关掉服务
root@node3:~# redis-cli -a wm521314 shutdown
root@node3:~# tail -f /apps/redis/log/redis-6379.log
14814:M 26 May 2022 13:12:16.229 # User requested shutdown...
14814:M 26 May 2022 13:12:16.229 * Saving the final RDB snapshot before exiting.
14814:M 26 May 2022 13:12:16.262 * DB saved on disk
14814:M 26 May 2022 13:12:16.262 * Removing the pid file.
14814:M 26 May 2022 13:12:16.264 # Redis is now ready to exit, bye bye...
#查看端口是没有6379端口的了
root@node3:~# ss -tnl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 64 0.0.0.0:31400 0.0.0.0:*
LISTEN 0 128 0.0.0.0:111 0.0.0.0:*
LISTEN 0 128 0.0.0.0:46544 0.0.0.0:*
LISTEN 0 128 0.0.0.0:12564 0.0.0.0:*
LISTEN 0 128 0.0.0.0:11956 0.0.0.0:*
LISTEN 0 128 127.0.0.53%lo:53 0.0.0.0:*
LISTEN 0 128 0.0.0.0:22 0.0.0.0:*
LISTEN 0 100 0.0.0.0:25 0.0.0.0:*
LISTEN 0 128 127.0.0.1:6010 0.0.0.0:*
LISTEN 0 128 127.0.0.1:6011 0.0.0.0:*
LISTEN 0 64 0.0.0.0:2049 0.0.0.0:*
LISTEN 0 128 [::]:15110 [::]:*
LISTEN 0 64 [::]:12104 [::]:*
LISTEN 0 128 [::]:31178 [::]:*
LISTEN 0 128 [::]:20206 [::]:*
LISTEN 0 128 [::]:111 [::]:*
LISTEN 0 128 [::]:22 [::]:*
LISTEN 0 100 [::]:25 [::]:*
LISTEN 0 128 [::1]:6010 [::]:*
LISTEN 0 128 [::1]:6011 [::]:*
LISTEN 0 64 [::]:2049 [::]:*
#现在在查看一下每个节点的对应关系
root@node1:~# redis-cli -a wm521314 cluster nodes
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
8f463789ccd8638709df9611270b2c0cd83984d5 10.1.2.215:6379@16379 slave 2d04605711615ba0acbf2a098c9c79c59b23f408 0 1653570977153 1 connected
d1112ea7d3bed02b6b4e1d89aa19fd3a38568ffd 10.1.2.217:6379@16379 slave 1e79791c833562821282d9aec31f4d116fc5e1c7 0 1653570977000 2 connected
2d04605711615ba0acbf2a098c9c79c59b23f408 10.1.2.208:6379@16379 myself,master - 0 1653570976000 1 connected 0-5460
285c027937cf19ed100efda1b5116c4bae04e50a 10.1.2.213:6379@16379 master - 0 1653570978165 7 connected 10923-16383
1e79791c833562821282d9aec31f4d116fc5e1c7 10.1.2.209:6379@16379 master - 0 1653570977000 2 connected 5461-10922
bbc82d4f8a1c6c062a88711a32d1ac08dc59a647 10.1.2.210:6379@16379 master,fail - 1653570736617 1653570733597 3 disconnected
#10.1.2.213这里会发现自动提升为新的master
root@node4:~# redis-cli -a wm521314 INFO replication
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
# Replication
role:master
connected_slaves:0
master_failover_state:no-failover
master_replid:eeab9e0bbcf0c124a6ef96a2bd91a7215b378f36
master_replid2:4d10bc7e1a4ae847d62a198d0b9eef1729a01af8
master_repl_offset:138940
second_repl_offset:138941
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:138940
root@node4:~# tail -f /apps/redis/log/redis-6379.log
15059:S 26 May 2022 13:12:33.778 * FAIL message received from d1112ea7d3bed02b6b4e1d89aa19fd3a38568ffd about bbc82d4f8a1c6c062a88711a32d1ac08dc59a647
15059:S 26 May 2022 13:12:33.871 # Start of election delayed for 892 milliseconds (rank #0, offset 138940).
15059:S 26 May 2022 13:12:34.276 * Connecting to MASTER 10.1.2.210:6379
15059:S 26 May 2022 13:12:34.276 * MASTER <-> REPLICA sync started
15059:S 26 May 2022 13:12:34.277 # Error condition on socket for SYNC: Connection refused
15059:S 26 May 2022 13:12:34.782 # Starting a failover election for epoch 7.
15059:S 26 May 2022 13:12:34.806 # Failover election won: I'm the new master.
15059:S 26 May 2022 13:12:34.806 # configEpoch set to 7 after successful failover
15059:M 26 May 2022 13:12:34.806 * Discarding previously cached master state.
15059:M 26 May 2022 13:12:34.806 # Setting secondary replication ID to 4d10bc7e1a4ae847d62a198d0b9eef1729a01af8, valid up to offset: 138941. New replication ID is eeab9e0bbcf0c124a6ef96a2bd91a7215b378f362.8、恢复故障节点node3自动成为slave节点
root@node3:~# systemctl restart redis
root@node3:~# ss -tnl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 64 0.0.0.0:31400 0.0.0.0:*
LISTEN 0 511 0.0.0.0:6379 0.0.0.0:*
LISTEN 0 128 0.0.0.0:111 0.0.0.0:*
LISTEN 0 128 0.0.0.0:46544 0.0.0.0:*
LISTEN 0 128 0.0.0.0:12564 0.0.0.0:*
LISTEN 0 128 0.0.0.0:11956 0.0.0.0:*
LISTEN 0 128 127.0.0.53%lo:53 0.0.0.0:*
LISTEN 0 128 0.0.0.0:22 0.0.0.0:*
LISTEN 0 100 0.0.0.0:25 0.0.0.0:*
LISTEN 0 128 127.0.0.1:6010 0.0.0.0:*
LISTEN 0 511 0.0.0.0:16379 0.0.0.0:*
LISTEN 0 64 0.0.0.0:2049 0.0.0.0:*
LISTEN 0 128 [::]:15110 [::]:*
LISTEN 0 64 [::]:12104 [::]:*
LISTEN 0 128 [::]:31178 [::]:*
LISTEN 0 128 [::]:20206 [::]:*
LISTEN 0 128 [::]:111 [::]:*
LISTEN 0 128 [::]:22 [::]:*
LISTEN 0 100 [::]:25 [::]:*
LISTEN 0 128 [::1]:6010 [::]:*
LISTEN 0 64 [::]:2049 [::]:*
#查看集群的状态文件，会发现node3自动上线成为slave节点了
root@node3:~# cat /apps/redis/data/nodes-6379.conf
285c027937cf19ed100efda1b5116c4bae04e50a 10.1.2.213:6379@16379 master - 0 1653571237158 7 connected 10923-16383
bbc82d4f8a1c6c062a88711a32d1ac08dc59a647 10.1.2.210:6379@16379 myself,slave 285c027937cf19ed100efda1b5116c4bae04e50a 0 1653571237146 7 connected
1e79791c833562821282d9aec31f4d116fc5e1c7 10.1.2.209:6379@16379 master - 0 1653571237158 2 connected 5461-10922
2d04605711615ba0acbf2a098c9c79c59b23f408 10.1.2.208:6379@16379 master - 0 1653571237158 1 connected 0-5460
d1112ea7d3bed02b6b4e1d89aa19fd3a38568ffd 10.1.2.217:6379@16379 slave 1e79791c833562821282d9aec31f4d116fc5e1c7 1653571237157 1653571237146 2 connected
8f463789ccd8638709df9611270b2c0cd83984d5 10.1.2.215:6379@16379 slave 2d04605711615ba0acbf2a098c9c79c59b23f408 0 1653571237158 1 connected
vars currentEpoch 7 lastVoteEpoch 0
root@node3:~# redis-cli -a wm521314 info replication
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
# Replication
role:slave
master_host:10.1.2.213
master_port:6379
master_link_status:up
master_last_io_seconds_ago:3
master_sync_in_progress:0
slave_read_repl_offset:139122
slave_repl_offset:139122
slave_priority:100
slave_read_only:1
replica_announced:1
connected_slaves:0
master_failover_state:no-failover
master_replid:eeab9e0bbcf0c124a6ef96a2bd91a7215b378f36
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:139122
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:138941
repl_backlog_histlen:182
#10.1.2.213主机上查看主从关系
root@node4:~# redis-cli -a wm521314 -c INFO replication
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
# Replication
role:master
connected_slaves:1
slave0:ip=10.1.2.210,port=6379,state=online,offset=139164,lag=0
master_failover_state:no-failover
master_replid:eeab9e0bbcf0c124a6ef96a2bd91a7215b378f36
master_replid2:4d10bc7e1a4ae847d62a198d0b9eef1729a01af8
master_repl_offset:139164
second_repl_offset:138941
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:139164
#查看现在集群每个节点的对应关系
root@node1:~# redis-cli -a wm521314 cluster nodes
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
8f463789ccd8638709df9611270b2c0cd83984d5 10.1.2.215:6379@16379 slave 2d04605711615ba0acbf2a098c9c79c59b23f408 0 1653571482198 1 connected
d1112ea7d3bed02b6b4e1d89aa19fd3a38568ffd 10.1.2.217:6379@16379 slave 1e79791c833562821282d9aec31f4d116fc5e1c7 0 1653571481192 2 connected
2d04605711615ba0acbf2a098c9c79c59b23f408 10.1.2.208:6379@16379 myself,master - 0 1653571481000 1 connected 0-5460
285c027937cf19ed100efda1b5116c4bae04e50a 10.1.2.213:6379@16379 master - 0 1653571482000 7 connected 10923-16383
1e79791c833562821282d9aec31f4d116fc5e1c7 10.1.2.209:6379@16379 master - 0 1653571483202 2 connected 5461-10922
bbc82d4f8a1c6c062a88711a32d1ac08dc59a647 10.1.2.210:6379@16379 slave 285c027937cf19ed100efda1b5116c4bae04e50a 0 1653571481000 7 connected2.8、附一键安装redis的脚本
#!/bin/bash
SRC_DIR=/usr/local/src
COLOR="echo -e \\033[01;31m"
END='\033[0m'
CPUS=`lscpu | awk '/^CPU\(s\)/{print $2}'`
URL='https://download.redis.io/releases/'
VERSION=redis-6.2.7
PASSWORD=wm521314
INSTALL_DIR=/apps/redis
os() {
if grep -Eqi "CentOS" /etc/issue || grep -Eq "CentOS" /etc/*-release;then
rpm -q redhat-lsb-core &> /dev/null || { ${COLOR}"安装lsb_release工具"${END};yum -y install redhat-lsb-core &> /dev/null; }
fi
OS_ID=`lsb_release -is`
}
install() {
if [ ${OS_ID} == "CentOS" ] &> /dev/null;then
yum -y install gcc jemalloc-devel || { ${COLOR}"安装软件包失败，请检查网络配置"${END}; exit; }
rpm -q wget &> /dev/null || yum -y install wget &> /dev/null
else
apt -y install make gcc libjemalloc-dev || { ${COLOR}"安装软件包失败，请检查网络配置"${END}; exit; }
fi
cd ${SRC_DIR}
wget ${URL}${VERSION}.tar.gz || { ${COLOR}"Redis源码下载失败"${END}; exit; }
tar xf ${VERSION}.tar.gz
cd ${VERSION}
make -j ${CPUS} PREFIX=${INSTALL_DIR} install && ${COLOR}"Redis编译安装完成"${END} || { ${COLOR}"Redis编译安装失败"${END}; exit; }
ln -s ${INSTALL_DIR}/bin/redis-* /usr/bin/
mkdir -p ${INSTALL_DIR}/{etc,log,data,run}
cp redis.conf ${INSTALL_DIR}/etc/
sed -i -e 's/bind 127.0.0.1.*/bind 0.0.0.0/' -e "/# requirepass/a requirepass ${PASSWORD}" -e "/^dir .*/c dir ${INSTALL_DIR}/data/" -e "/logfile .*/c logfile ${INSTALL_DIR}/log/redis-6379.log" -e "/^pidfile .*/c pidfile ${INSTALL_DIR}/run/redis_6379.pid" ${INSTALL_DIR}/etc/redis.conf
if id redis &> /dev/null ;then
${COLOR}"Redis用户已经存在"${END}
else
useradd -r -s /sbin/nologin redis
${COLOR}"Redis用户创建成功"${END}
fi
chown -R redis.redis ${INSTALL_DIR}
cat >> /etc/sysctl.conf <<-EOF
net.core.somaxconn = 1024
vm.overcommit_memory = 1
EOF
sysctl -p
if [ ${OS_ID} == "CentOS" ] &> /dev/null;then
echo 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' >> /etc/rc.d/rc.local
chmod +x /etc/rc.d/rc.local
else
cat >> /lib/systemd/system/rc-local.service <<-EOF
[Install]
WantedBy=multi-user.target
EOF
echo '#!/bin/bash' > /etc/rc.local
echo 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' >> /etc/rc.local
chmod +x /etc/rc.local
fi
cat > /lib/systemd/system/redis.service <<-EOF
[Unit]
Description=Redis persistent key-value database
After=network.target
[Service]
ExecStart=${INSTALL_DIR}/bin/redis-server ${INSTALL_DIR}/etc/redis.conf --supervised systemd
ExecStop=/bin/kill -s QUIT \$MAINPID
#Type=notify
User=redis
Group=redis
RuntimeDirectory=redis
RuntimeDirectoryMode=0755
[Install]
WantedBy=multi-user.target
EOF
systemctl daemon-reload
systemctl enable --now redis &> /dev/null && ${COLOR}"Redis服务启动成功,Redis信息如下:"${END} || { ${COLOR}"Redis服务启动失败"${END};exit; }
sleep 1
redis-cli -a ${PASSWORD} INFO Server 2> /dev/null
}
main() {
os
install
}
main
