Implementing Redis Master-Slave Replication

Redis master-slave replicaiton enables data redundancy and read scalability by allowing one Redis server (master) to replicate its data to one or more replica servers (slaves). The master handles write operations while slaves serve read requests, creating a one-to-many replication topology.

Cofniguring Master Server

Edit the master Redis configuration file:

# /etc/redis/redis.conf
bind 192.168.1.10 127.0.0.1
port 6379
daemonize yes
supervised systemd
pidfile /var/run/redis/redis-server.pid
logfile /var/log/redis/redis-server.log
save 900 1
save 300 10
save 60 10000
stop-writes-on-bgsave-error no
dbfilename master-dump.rdb
dir /var/lib/redis
requirepass securepass123

Start the master service and verify data:

$ redis-server /etc/redis/redis.conf
$ redis-cli -a securepass123
127.0.0.1:6379> KEYS *
1) "user:1001"
2) "cache:session"
3) "counter:views"

Configuring Slave Server

Edit the slave configuraton file:

# /etc/redis/redis-slave.conf
bind 192.168.1.20 127.0.0.1
port 6380
daemonize yes
pidfile /var/run/redis/redis-slave.pid
logfile /var/log/redis/redis-slave.log
dbfilename slave-dump.rdb
dir /var/lib/redis-slave
requirepass securepass123
slaveof 192.168.1.10 6379
masterauth securepass123
slave-read-only yes

Start the slave service and verify replication status:

$ redis-server /etc/redis/redis-slave.conf
$ redis-cli -p 6380 -a securepass123
127.0.0.1:6380> INFO replication
# Replication
role:slave
master_host:192.168.1.10
master_port:6379
master_link_status:up

127.0.0.1:6380> KEYS *
1) "user:1001"
2) "cache:session"
3) "counter:views"

Runtime Replication Management

Promote slave to master:

127.0.0.1:6380> SLAVEOF no one
OK
127.0.0.1:6380> INFO replication
role:master

Reconfigure as slave:

127.0.0.1:6380> SLAVEOF 192.168.1.10 6379
OK
127.0.0.1:6380> CONFIG SET masterauth securepass123
OK