Install Redis master-slave-sentinel on linux

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Before start

  1. Download and install redis from official site
  2. redis excutable commands are under bin folder, configs are under etc folder, logs are under var folder

Redis master

Configuration

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# Run as background service
daemonize yes

# for daemonized pid file path
pidfile "/var/run/redis_6379.pid"

# specify log file path
logfile "/var/log/6379.log"

# Set the number of databases, from 0 to 16
databases 16

# specify db dump path
dbfilename dump.rdb

# db will written into this directory
dir "/var/dump/"

# specify redis instance port
port 6379

# bind your public/local ip, to let you access by your ip address
bind ip1 ip2 ip3

# Setup your password (recommend!)
requirepass password

Start Master

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redis-server /redis/etc/{master.config}

Verify Master

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redis-cli -h 127.0.0.1 -p 6379 -a password info replication

You should see something like this, if you have slave you will see number of connected_slaves :

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[root@lx-uk-ssm129 redis]# bin/redis-cli -p 6379 -a password info replication
# Replication
role:master
connected_slaves:2
slave0:ip=127.0.0.1,port=8880,state=online,offset=110104326,lag=1
slave1:ip=127.0.0.1,port=8879,state=online,offset=110104386,lag=1
master_repl_offset:110104386
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:109055811
repl_backlog_histlen:1048576

Redis slave

Configuration

Repeat master configuration, change your port, bind ip…etc, the only difference are two lines :

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# Specify master instance location
slaveof 127.0.0.1 6379

# For master authentication
masterauth password

Start Slave

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redis-server /redis/etc/{slave.config}

Verify Slave

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redis-cli -h 127.0.0.1 -p 6379 -a password info replication

You will see something like this :

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[root@example redis]# bin/redis-cli -h 127.0.0.1 -p 8879 -a password info replication
# Replication
role:slave
master_host:127.0.0.1
master_port:6379
master_link_status:up
master_last_io_seconds_ago:1
master_sync_in_progress:0
slave_repl_offset:108498274
slave_priority:100
slave_read_only:1
connected_slaves:0
master_repl_offset:0
repl_backlog_active:0
repl_backlog_size:1048576
repl_backlog_first_byte_offset:0
repl_backlog_histlen:0

Sentinel

Create sentinel.conf

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# port to run sentinel
port 26379
dir /tmp

# Consider master objectively down only if at least number of sentinels agree
sentinel monitor master 127.0.0.1 6379 1

# How many seconds master not responding will consider it as down
sentinel down-after-milliseconds master 3000

# How many slave could sentinel reconfigure simultaneously, use low number to prevent all instance unreachable at about the same time
sentinel parallel-syncs master 1

# Sentinel failover timeout
sentinel failover-timeout master 18000

Start sentinel

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redis-server sentinel.conf --sentinel

Verify sentinel

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redis-cli -h 127.0.0.1 -p 26379 info sentinel

Useful commands

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# check redis instance
ps –ef | grep redis

# shutdown redis process
kill PID

A little note for yaml format

  • Normally you don’t need quote for string,
  • If string contains special character, use quote "" or ''
  • Difference between "" or '' is double quote parse escape character but single quote doesn’t