Set the VIP in Redis-sentinel's client-reconfig-script script

Set the VIP in Redis-sentinel's client-reconfig-script script

When using Redis-sentinel for redundancy, how to use the VIP in different ways, I think the use of Client-reconfig-script script is a feasible way, let's try.

Environment

CentOS 6.5 x86_64redis-2.8.9-1.el6.remi.x86_64

Three machines make up an available Redis cluster.
Port default 6379, in these three Redis, install Redis-sentinel separately.

redis1 192.168.0.1/24
redis2 192.168.0.2/24
redis3 192.168.0.3/24

Redis,redis-sentinel Installation

Use Yum to install Remi, Redis 2.8.
Set REIDS1 as master and copy to other slave.

 
yum install --enablerepo=epel,remi redis -y sed -i "s|bind 127.0.0.1|bind 0.0.0.0|g" /etc/redis.conf
service redis start
chkconfig redis on

Set Redis2, Redis3 as slave.

redis-cli127.0.0.1:6379SLAVEOF 192.168.0.1 6379

VIP Settings Script

This is the script executed at failover.
The parameters shown below are passed to the script Client-reconfig-script.

<master-name><role><state><from-ip><from-port><to-ip><to-port>

The 6th add VIP, will become a master, the other is to delete the VIP. When failover, using only IP commands can produce ARP problems, so use the arping command to throw Grap. Root permission is required when using the IP, arping command, and sudo is used here to execute the command.

vim /var/lib/redis/failover.sh chmod 755 /var/lib/redis/failover.sh chown redis: /var/lib/redis/failover.sh echo -e "redis\tALL=(ALL)\tNOPASSWD:/sbin/ip,NOPASSWD:/sbin/arping" > /etc/sudoers.d/redis
sed -i "s|Defaults.*requiretty|#Defaults\trequiretty|" /etc/sudoers
chmod 440 /etc/sudoers.d/redis

#! / bin / bash

MASTER_IP = $ {6}
MY_IP = ‘192.168.0.1’ # IP of each server itself
VIP = ‘192.168.0.4’ # VIP
NETMASK = ‘24 ’# Netmask
INTERFACE = ‘eth0’ # interface

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

Redis-sentinel settings

Start setting up Redis-sentonel.
You only need to manually set the VIP at the first time.

 
vim /etc/redis-sentinel.conf

service redis-sentinel start
chkconfig redis-sentinel on ip addr add 192.168.0.4/24 dev eth0
# sentinel.conf port 26379 logfile /var/log/redis/sentinel.log sentinel monitor mymaster 192.168.0.1 6379 2 sentinel down-after-milliseconds mymaster 3000 sentinel parallel-syncs mymaster 1 sentinel failover-timeout mymaster 60000 sentinel client-reconfig-script mymaster /var/lib/redis/failover.sh

Conclusion

After that you can try kill master instead of downtime to test failover, which I think is a good and easy way to implement.
Sentinel Down-after-milliseconds MyMaster 3000
Redis downtime is detected in about 3 seconds. In a more hostile environment, you can try to reduce this value.

Original: http://blog.youyo.info/blog/2014/05/24/redis-cluster/
B.com/benweet/stackedit

Set the VIP in Redis-sentinel's client-reconfig-script script