Redis one master multi slave cluster setup

Basic concepts ：

Single Redis If it goes down for some reason , May lead to Redis Service not available , Master-slave replication can be used to realize one master and multiple slaves , The master node is responsible for Write The operation of , Slave node responsible read The operation of , Data is periodically synchronized from the master node to the slave node , The problem of ensuring data consistency .

One The cluster is built in a tree mode

1. Here's the picture , Get ready 7 Servers , Master node （master) IP by 192.168.1.100

2. Cluster building

a. 192.168.1.100  Master node (master) No configuration required

After all slave nodes are configured , Use info replication You can see At present role: master Master node , multiple slave It's its slave node

b. 192.168.1.101 and 192.168.1.102  Configure slave

vim redis.config 

increase slaveof Point to master node

Add the primary node password

 Related configuration redis.conf
# replicaof <masterip> <masterport>
slaveof 192.168.1.100 6379

#redis password 
masterauth 123456  

info replication View cluster information , You can see the current role role: slave 

c. 192.168.1.201 and 192.168.1.301  Configure slave

 Related configuration redis.conf
# replicaof <masterip> <masterport>
slaveof 192.168.1.101 6379

#redis password 
masterauth 123456  

d. 192.168.1.202 and  192.168.1.302  Configure slave

 Related configuration redis.conf
# replicaof <masterip> <masterport>
slaveof 192.168.1.102 6379

#redis password 
masterauth 123456  

Configuration is complete here , The master node is used for reading and writing , The slave node can only read .

Be careful ： It is impossible to achieve absolute strong consistency in the distributed domain   After all, there are network reasons

Redis The role of master-slave replication ：

1. Realization Redis colony
2. Data backup
3. Read / write separation

Master-slave replication requires attention ：  The master node will synchronize the data to the slave node in incremental or full form to ensure the consistency of the data , The efficiency comparison of traditional one master multi synchronization   It is recommended to use tree form .

Master slave replication principle process ：

1. You need to start from redis The server is configured in slaveof perform Lord redis service ip Address and port number

192.168.1.100：6379 （ Main services ） And password ;

2. from Redis Server and master Redis Server setup Socket A long connection ;

3. The data is synchronized to the slave in full and incremental form Redis The server

  Total quantity ： from Redis When it was first started  （ Binary execution dump  file ） rdb

  The incremental ： Lord Redis Every time there's a new one set When you ask  aof Log files

There are still some defects in master-slave replication ？

If the primary node goes down , May lead to the whole Redis The service cannot realize write operation, which requires us to manually modify the new master operation .