结合keepalived实现redis群集高可用故障自动切换
系统架构图:我们所要实现的目的很简单,
104,107 为keepalive和redis主从架构，其余服务器比如105、106均为redis从库并且挂在vip 192.168.56.180下面。
主keepalive负责主要日常工作，从keepalive担任备机角色，一旦主keepalive挂掉，从keepalive服务器立即使从redis转变角色切换成master状态开始接管任务提供服务，实现业务的无缝切换,当挂掉的服务器修好上线后继续担任主的角色，从库会自动切换到slave状态并且不影响挂载在vip下的从redis的数据同步，一满足高并发架构的需求。
keepalive在ubuntu的安装很简单
apt-get install libssl-dev
apt-get install openssl
apt-get install libpopt-dev
apt-get install keepalived
redis的安装也很简单:
网上很多方法，也可参考我的另一篇文章: redis的shell安装脚本,实现在linux下本机主从架构
网上有一篇郭冬的一篇文章给了我很大启发故拿来参考:通过Keepalived实现Redis Failover自动故障切换，
下面我们看192.168.56.104主keepalived的配置
/etc/keepalived/keepalived.conf
global_defs { notification_email {
409011500@qq.com
}
notification_email_from409011500@qq.com
smtp_server 127.0.0.1（如果本机配置的话）
smtp_connect_timeout 30
router_id redis-ha
}
vrrp_script chk_redis {
script "/home/lhb/sh/redis_check.sh" ###监控脚本
interval 2 ###监控时间
}
vrrp_instance VI_1 {
state MASTER ###设置为MASTER
interface eth0 ###监控网卡
virtual_router_id 52
priority 101 ###权重值
authentication {
auth_type PASS ###加密
auth_pass redis ###密码
}
track_script {
chk_redis ###执行上面定义的chk_redis
}
virtual_ipaddress {
192.168.56.180 ###VIP
}
notify_master /home/lhb/sh/redis_master.sh
notify_backup /home/lhb/sh/redis_backup.sh
}
/home/lhb/sh/redis_master.sh
#!/bin/bash
REDISCLI="/usr/local/redis/bin/redis-cli"
LOGFILE="/usr/local/redis/log/keepalived-redis-state.log"
echo "" >> $LOGFILE
date >> $LOGFILE
echo "Being master...." >> $LOGFILE 2>&1
echo "Run SLAVEOF cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF 192.168.56.107 6379 >> $LOGFILE2>&1
sleep 10 #延迟10秒以后待数据同步完成后再取消同步状态
echo "Run SLAVEOF NO ONE cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF NO ONE >> $LOGFILE 2>&1
/home/lhb/sh/redis_backup.sh
#!/bin/bash
REDISCLI="/usr/local/redis/bin/redis-cli"
LOGFILE="/usr/local/redis/log/keepalived-redis-state.log"
echo "" >> $LOGFILE
date >> $LOGFILE
echo "Being slave...." >> $LOGFILE 2>&1
sleep 15 #延迟15秒待数据被对方同步完成之后再切换主从角色
echo "Run SLAVEOF cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF 192.168.56.107 6379 >> $LOGFILE2>&1
/usr/local/redis/etc/redis.conf
daemonize yes
pidfile /var/run/redis.pid
port 6379
tcp-backlog 511
timeout 0
tcp-keepalive 0
loglevel notice
logfile "/usr/local/redis/log/redis.log"
databases 16
save 900 1
save 300 10
save 60 10000
stop-writes-on-bgsave-error yes
rdbcompression yes
rdbchecksum yes
dbfilename dump.rdb
dir /usr/local/redis/data
slave-serve-stale-data yes
slave-read-only no
repl-disable-tcp-nodelay no
slave-priority 100
appendonly yes
appendfilename "appendonly.aof"
appendfsync everysec
no-appendfsync-on-rewrite no
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb
lua-time-limit 5000
slowlog-log-slower-than 10000
slowlog-max-len 128
notify-keyspace-events ""
hash-max-ziplist-entries 512
hash-max-ziplist-value 64
list-max-ziplist-entries 512
list-max-ziplist-value 64
set-max-intset-entries 512
zset-max-ziplist-entries 128
zset-max-ziplist-value 64
activerehashing yes
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit slave 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60
hz 10
aof-rewrite-incremental-fsync yes
192.168.56.107从keepalived的配置
/etc/keepalived/keepalived.conf
global_defs { notification_email {
409011500@qq.com
}
notification_email_from 409011500@qq.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id redis-ha
}
vrrp_script chk_redis {
script "/home/lhb/sh/redis_check.sh" ###监控脚本
interval 2 ###监控时间
}
vrrp_instance VI_1 {
state BACKUP ###设置为BACKUP
interface eth0 ###监控网卡
virtual_router_id 52
priority 100 ###比MASTRE权重值低
authentication {
auth_type PASS
auth_pass redis ###密码与MASTRE相同
}
track_script {
chk_redis ###执行上面定义的chk_redis
}
virtual_ipaddress {
192.168.56.180 ###VIP
}
notify_master /home/lhb/sh/redis_master.sh
notify_backup /home/lhb/sh/redis_backup.sh
}
/home/lhb/sh/redis_master.sh
#!/bin/bash
REDISCLI="/usr/local/redis/bin/redis-cli"
LOGFILE="/usr/local/redis/log/keepalived-redis-state.log"
echo "" >> $LOGFILE
date >> $LOGFILE
echo "Being master...." >> $LOGFILE 2>&1
echo "Run SLAVEOF cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF 192.168.56.104 6379 >> $LOGFILE2>&1
sleep 10 #延迟10秒以后待数据同步完成后再取消同步状态
echo "Run SLAVEOF NO ONE cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF NO ONE >> $LOGFILE 2>&1
/home/lhb/sh/redis_backup.sh
#!/bin/bash
REDISCLI="/usr/local/redis/bin/redis-cli"
LOGFILE="/usr/local/redis/log/keepalived-redis-state.log"
echo "" >> $LOGFILE
date >> $LOGFILE
echo "Being slave...." >> $LOGFILE 2>&1
sleep 15 #延迟15秒待数据被对方同步完成之后再切换主从角色
echo "Run SLAVEOF cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF 192.168.56.104 6379 >> $LOGFILE2>&1
/home/lhb/sh/redis_check.sh
#!/bin/bash
ALIVE=`/usr/local/redis/bin/redis-cli PING`
if [ "$ALIVE" == "PONG" ]; then
echo $ALIVE
exit 0
else
echo $ALIVE
exit 1
fi
/usr/local/redis/etc/redis_slave.conf
daemonize yes
pidfile /var/run/redis_salve.pid
port 6379
tcp-backlog 511
timeout 0
tcp-keepalive 0
loglevel notice
logfile "/usr/local/redis/log/redis_slave.log"
databases 16
save 900 1
save 300 10
save 60 10000
stop-writes-on-bgsave-error yes
rdbcompression yes
rdbchecksum yes
dbfilename dump_salve.rdb
dir /usr/local/redis/data
slave-serve-stale-data yes
slave-read-only no
repl-disable-tcp-nodelay no
slave-priority 100
appendonly yes
appendfilename "appendonly.aof"
appendfsync everysec
no-appendfsync-on-rewrite no
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb
lua-time-limit 5000
slowlog-log-slower-than 10000
slowlog-max-len 128
notify-keyspace-events ""
hash-max-ziplist-entries 512
hash-max-ziplist-value 64
list-max-ziplist-entries 512
list-max-ziplist-value 64
set-max-intset-entries 512
zset-max-ziplist-entries 128
zset-max-ziplist-value 64
activerehashing yes
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit slave 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60
hz 10
aof-rewrite-incremental-fsync yes
SLAVEOF 192.168.56.104 6379
192.168.56.105、192.168.56.106 redis配置文件相同:
/usr/local/redis/etc/redis_salve.conf
daemonize yes
pidfile /var/run/redis_salve.pid
port 6379
tcp-backlog 511
timeout 0
tcp-keepalive 0
loglevel notice
logfile "/usr/local/redis/log/redis_slave.log"
databases 16
save 900 1
save 300 10
save 60 10000
stop-writes-on-bgsave-error yes
rdbcompression yes
rdbchecksum yes
dbfilename dump_salve.rdb
dir /usr/local/redis/data
slave-serve-stale-data yes
slave-read-only no
repl-disable-tcp-nodelay no
slave-priority 100
appendonly no
appendfilename "appendonly.aof"
appendfsync everysec
no-appendfsync-on-rewrite no
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb
lua-time-limit 5000
slowlog-log-slower-than 10000
slowlog-max-len 128
notify-keyspace-events ""
hash-max-ziplist-entries 512
hash-max-ziplist-value 64
list-max-ziplist-entries 512
list-max-ziplist-value 64
set-max-intset-entries 512
zset-max-ziplist-entries 128
zset-max-ziplist-value 64
activerehashing yes
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit slave 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60
hz 10
aof-rewrite-incremental-fsync yes
SLAVEOF 192.168.56.180 6379
好了，下面我们就来展示一下是否是我们期待的那样？
启动192.168.56.104，192.168.56.107上的redis,keepalvied，以及192.168.56.105,192.168.56.106上的redis
在192.168.56.104 我们看到以下结果，已经获取vip:192.168.56.180
在192.168.56.107 我们看到以下结果,并没有获得vip192.168.56.180
在192.168.56.105,192.168.56.106我们看到相同结果redis挂载在vip:192.168.56.180下
这时我们把192.168.56.104下的redis给关闭掉，看一下结果:vip已经释放
然后到192.168.56.107下看一下信息: 已经获取vip，并且redis已经从salve切换到master，并且从库105、106状态均为online
192.168.56.105、192.168.56.106 redis结果:一直挂载在vip下面并且link_status处于up状态
由此可见，当主redis挂掉后，备机上的redis立即切换为master,并且不影响业务正常运行。
我们然后把主上redis从新启动,看到下面结果: 主服务器获取vip
redis信息:我们可以看到192.168.56.107备机已经出现在master的slave列表中
然后切换到:192.168.56.107看一下信息: 已经释放vip，并且redis已经从master切换到slave状态，并且指向的master是192.168.56.104
在看192.168.56.105、192.168.56.106 redis信息,亦然指向192.168.56.180
看到这里，已经满足我们系统架构最初的所有设想功能。有感兴趣的同学可以一起交流。谢谢
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