redis cluster的虚拟节点
转载
思路
有两台redis服务器，主197，备198，通过keepalived实现高可用.
1,若主197挂了，备198成为master,当197问题修复重启后，同步与198的差异数据。成为备胎。
2,若备198挂了，没有变动，198问题修复重启后同步与197的差异数据，继续当备胎。
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需要分配同网段的虚拟IP （VIP)
安装
1，两台服务器安装redis,keepalived。
redis安装略。
yum -y install keepalived 默认配置文件在 /etc/keepalived/
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2，将默认的keepalived.conf清空：
配置
（以下配置文件尽量自己手写，有助于理解。注释我就不加 # 号了。嘻嘻嘻嘻）
主keepalived配置
global_defs {
router_id redis197 随便写，不一样就行。
}
vrrp_script chk_redis 检查redis状态的脚本文件
{
script "/etc/keepalived/scripts/redis_check.sh 127.0.0.1 6379 houqi" 文件地址及参数（IP PORT PASSWORD)
interval 2 每隔2s执行
timeout 2 超过2s超时
fall 3
}
vrrp_instance redis {
state MASTER 主为master 备胎为 backup
interface eth0 当前可用网卡 ip a 可查看
virtual_router_id 50 路由IP 主从需一直
priority 150 优先级，主必须大于备胎
nopreempt # no seize,must add
advert_int 1
authentication { #all node must same
auth_type PASS
auth_pass 1111 主从交互的密码，需一致
}
virtual_ipaddress {
10.120.112.190/24 虚拟IP
}
track_script {
chk_redis 执行上面检查redis状态脚本
}
notify_master "/etc/keepalived/scripts/redis_master.sh 127.0.0.1 10.120.112.198 6379 houqi" 切换状态时执行的脚本
notify_backup "/etc/keepalived/scripts/redis_backup.sh 127.0.0.1 10.120.112.198 6379 houqi"
notify_fault /etc/keepalived/scripts/redis_fault.sh
notify_stop /etc/keepalived/scripts/redis_stop.sh
}
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从keepalived配置
global_defs {
router_id redis198 名字与主不同
}
vrrp_script chk_redis
{
script "/etc/keepalived/scripts/redis_check.sh 127.0.0.1 6379 houqi"
interval 2
timeout 2
fall 3
}
vrrp_instance redis {
state BACKUP 状态为backup
interface eth0
virtual_router_id 50 必须一样
priority 100 必须比主小
advert_int 1
authentication { #all node must same
auth_type PASS
auth_pass 1111 必须一样
}
virtual_ipaddress {
10.120.112.190/24
}
track_script {
chk_redis
}
notify_master "/etc/keepalived/scripts/redis_master.sh 127.0.0.1 10.120.112.197 6379 houqi"
notify_backup "/etc/keepalived/scripts/redis_backup.sh 127.0.0.1 10.120.112.197 6379 houqi"
notify_fault /etc/keepalived/scripts/redis_fault.sh
notify_stop /etc/keepalived/scripts/redis_stop.sh
}
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必要脚本文件
切换状态notify 时的脚本文件。
在/etc/keepalived 下新建文件夹 scripts
Keepalived在转换状态时会根据状态来呼叫：
当进入Master状态时会呼叫redis_master
当进入Backup状态时会呼叫redis_backup
当发现异常情况时进入Fault状态呼叫redis_fault
当Keepalived程序终止时则呼叫redis_stop
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主redis_master脚本
#!/bin/bash
REDISCLI="/usr/local/redis/bin/redis-cli -h $1 -p $3 -a $4" 连接redis客户端， $1 引用keepalived.conf里的对应的参数
LOGFILE="/var/log/keepalived-redis-state.log" 将结果写到这个日志
echo "[master]" >> $LOGFILE
date >> $LOGFILE 日期
echo "Being master...." >> $LOGFILE 2>&1
echo "Run MASTER cmd ..." >> $LOGFILE 2>&1
$REDISCLI SLAVEOF $2 $3 >> $LOGFILE 差异备份
sleep 10 #delay 10 s wait data async cancel sync 10s时间来备份
echo "Run SLAVEOF NO ONE cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF NO ONE >> $LOGFILE 2>&1 取消成为另一台的从服务器。
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主redis_backup脚本
#!/bin/bash
REDISCLI="/usr/local/redis/bin/redis-cli -a houqi"
LOGFILE="/var/log/keepalived-redis-state.log"
echo "[backup]" >> $LOGFILE
date >> $LOGFILE
echo "Run SLAVEOF cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF $2 $3 >> $LOGFILE 2>&1
# echo "Being slave...." >> $LOGFILE 2>&1
sleep 50 #delay 15 s wait data sync exchange role
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从redis_master脚本
#!/bin/bash
REDISCLI="/usr/local/redis/bin/redis-cli -h $1 -p $3 -a $4"
LOGFILE="/var/log/keepalived-redis-state.log"
echo "[master]" >> $LOGFILE
date >> $LOGFILE
echo "Being master...." >> $LOGFILE 2>&1
echo "Run SLAVEOF cmd ... " >> $LOGFILE
$REDISCLI SLAVEOF $2 $3 >> $LOGFILE 2>&1
#echo "SLAVEOF $2 cmd can't excute ... " >> $LOGFILE
sleep 10 ##delay 15 s wait data sync exchange role
echo "Run SLAVEOF NO ONE cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF NO ONE >> $LOGFILE 2>&1
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从redis_backup脚本
#!/bin/bash
REDISCLI="/usr/local/redis/bin/redis-cli -a houqi"
LOGFILE="/var/log/keepalived-redis-state.log"
echo "[BACKUP]" >> $LOGFILE
date >> $LOGFILE
echo "Being slave...." >> $LOGFILE 2>&1
echo "Run SLAVEOF cmd ..." >> $LOGFILE 2>&1
$REDISCLI SLAVEOF $2 $3 >> $LOGFILE
sleep 50 #delay 10 s wait data async cancel sync
exit(0)
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主从redis_fault
#!/bin/bash
LOGFILE=/var/log/keepalived-redis-state.log
echo "[fault]" >> $LOGFILE
date >> $LOGFILE
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主从redis_stop
#!/bin/bash
LOGFILE=/var/log/keepalived-redis-state.log
echo "[stop]" >> $LOGFILE
date >> $LOGFILE
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给脚本赋可执行权限
到此，197，198两台服务器已经通过VIP联系了起来，Java客户端只需要把IP写成VIP就行，端口还是6379.
注意：***
我写的时候遇到个问题，就是两台redis主从不能同步，slave始终是0，最后我想到是不是因为我的redis有密码，然后在两台redis的配置文件里都加了一行： masterauth houqi(我的密码) 然后发现主从可以同步数据了。做个记录，万一有人和我遇到同样的情况。
还有如果有密码的话，在那几个脚本里连接客户端的时候最好加上 -a 你的密码 , 以防因为密码原因导致失败。
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