Sentinel plus VIP drift to achieve high availability of Redis cluster

note

• First of all, I think these two blogs are better than mine:
  • redis (one master, two slaves and three sentinels) record
  • Use redis master-slave + sentinel + vip drift to build a redis high-availability cluster
• In fact, it can be built according to the steps, but when I tested it, it has been unsuccessful. I need to adjust the waiting data value in sentinel.conf as small as possible to see the effect as soon as possible.

aims

• Build a three-node Redis service cluster to meet the requirements of high availability
  • Unified IP: Three-node cluster exposes a unified IP address
  • High availability: the master node is down, and the slave node needs to quickly assume the master node
  • Read and write separation: the master node allows reading and writing, and the slave node is read only
  • Quick join: After the down node restarts, join the cluster and become the cluster slave node

The main steps

• Install three redis
• Modify the redis.conf file
• Modify sentinel.conf file
• First start redis one by one, if there is a problem, see if you can find the answer here: some pits in the middleware installation process
• Restart sentinel
• Configure VIP script and initialize

Pro test can use script

• redis.conf

protected-mode yes
port 6379
daemonize yes
bind 0.0.0.0
 
pidfile "/var/run/redis_6379.pid"
logfile "/etc/redis/redis.log"
 
dir "/etc/redis"
dbfilename "dump.rdb"
replica-read-only yes
 
requirepass "Sxxxxx4"
masterauth "Sxxxxxx4"

• sentinel.conf

port 26379
daemonize yes
protected-mode no
 
pidfile "/var/run/redis-sentinel.pid"
logfile "/etc/redis/sentinel.log"
dir "/tmp"
 
sentinel myid e09252859aced76c83958ef6686b739da9b2035f
sentinel deny-scripts-reconfig yes

sentinel monitor mymaster01 1xx.xx.xx.4 6379 2
sentinel down-after-milliseconds mymaster01 5000#尽可能小，才能很快看出效果
sentinel failover-timeout mymaster01 10000 #尽可能小，才能很快看出效果
sentinel auth-pass mymaster01 Spdb@1234

sentinel client-reconfig-script mymaster01 /etc/redis/transip.sh

• VIP drift script

#!/bin/bash
MASTER_IP=$6
LOCAL_IP='1x x x12'
VIP='1xxxx2'
NETMASK='24'
INTERFACE='eth0'

if [ ${MASTER_IP}=${LOCAL_IP} ]; then
    /sbin/ip  addr  add  ${VIP}/${NETMASK} dev ${INTERFACE}
    /sbin/arping    -q -c 3 -A ${VIP}  -I ${INTERFACE}
    exit 0
else
    /sbin/ip  addr  del  ${VIP}/${NETMASK} dev ${INTERFACE}
    exit 0
fi
exit 1