redis+Keepalived实现Redis主从复制

redis+Keepalived实现Redis主从复制：

环境：CentOs6.5
Master: 192.168.1.203
Slave:   192.168.1.204
Virtural IP Address (VIP): 192.168.1.205

所需软件：
keepalived-1.2.12.tar.gz
redis-2.8.7.tar.gz

实现功能：
当 Master 与 Slave 均运作正常时, Master负责服务，Slave负责Standby；
当 Master 挂掉，Slave 正常时, Slave接管服务，同时关闭主从复制功能；

一、安装配置前准备工作:

yum -y install gcc gcc+ gcc-c++ openssl openssl-devel pcre pcre-devel

Redis属于内存数据库，所以调优都集中到了内存上,需要将 vm.overcommit 设置为1
echo "vm.overcommit_memory=1" >> /etc/sysctl
sysctl -p

1.在主服务器192.168.1.203上面做下面操作
echo " 192.168.1.203 gc-xxooredis1" >> /etc/hosts
echo " 192.168.1.204 gc-xxooredis2" >> /etc/hosts
2.在从服务器192.168.1.204上面做下面操作
echo " 192.168.1.203 gc-xxooredis1" >> /etc/hosts
echo " 192.168.1.204 gc-xxooredis2" >> /etc/hosts

二、在Master和Slave上安装redis:

tar -zxvf redis-2.8.7.tar.gz
cd redis-2.8.7
make && make install
cd src
mkdir -p /usr/local/redis/bin
cp redis-server redis-cli redis-benchmark redis-check-aof redis-check-dump /usr/local/redis/bin/

mkdir -p /usr/local/redis/etc

将源码中的 redis.conf 复制到 /usr/local/redis/etc/
redis-2.8.7]# cp redis.conf /usr/local/redis/etc/

修改 /usr/local/redis/etc/redis.conf里面可以把 daemonize no 修改为daemonize yes

制作一个redis  init.d 的启动脚本：

 #!/bin/bash
 #
 # redis - this script starts and stops the redis-server daemon
 #
 # chkconfig:  -
 # description: Redis is a persistent key-value database
 # processname: redis-server
 # config:   /usr/local/redis/etc/redis.conf
 # pidfile:   /usr/local/redis/var/redis.pid

 source /etc/init.d/functions

 BIN="/usr/local/redis/bin"
 CONFIG="/usr/local/redis/etc/redis.conf"
 PIDFILE="/usr/local/redis/var/redis.pid"

 ### Read configuration
 [ -r "$SYSCONFIG" ] && source "$SYSCONFIG"

 RETVAL=
 prog="redis-server"
 desc="Redis Server"

 start() {

     if [ -e $PIDFILE ];then
        echo "$desc already running...."
        exit
     fi

     echo -n $"Starting $desc: "
     daemon $BIN/$prog $CONFIG

     RETVAL=$?
     echo
     [ $RETVAL -eq  ] && touch /var/lock/subsys/$prog
     return $RETVAL
 }

 stop() {
     echo -n $"Stop $desc: "
     killproc $prog
     RETVAL=$?
     echo
     [ $RETVAL -eq  ] && rm -f /var/lock/subsys/$prog $PIDFILE
     return $RETVAL
 }

 restart() {
   stop
   start
 }

 case "$1" in
  start)
     start
     ;;
  stop)
     stop
     ;;
  restart)
     restart
     ;;
  condrestart)
     [ -e /var/lock/subsys/$prog ] && restart
     RETVAL=$?
     ;;
  status)
     status $prog
     RETVAL=$?
     ;;
   *)
     echo $"Usage: $0 {start|stop|restart|condrestart|status}"
     RETVAL=
 esac

 exit $RETVAL

vim /etc/init.d/redis-server
chmod o+x /etc/init.d/redis-server
chkconfig --add redis-server
/etc/init.d/redis-server start

###########################################################################################
三、在Master和Slave上安装keepalived:

tar -zxvf keepalived-1.2.12.tar.gz
cd keepalived-1.2.12

./configure
make && make install

cp /usr/local/etc/rc.d/init.d/keepalived /etc/init.d/
cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/
chmod +x /etc/init.d/keepalived
chkconfig --add keepalived

mkdir /etc/keepalived
ln -s /usr/local/sbin/keepalived /usr/sbin

Keepalived在转换状态时会依照状态来呼叫：
当进入Master状态时会呼叫notify_master
当进入Backup状态时会呼叫notify_backup
当发现异常情况时进入Fault状态呼叫notify_fault
当Keepalived程序终止时则呼叫notify_stop

 Master上创建配置：

在Master上创建配置文件 keepalived.conf 如下
vim /etc/keepalived/keepalived.conf

 vrrp_script chk_redis {
 script "/etc/keepalived/scripts/redis_check.sh"
 interval
 }

 vrrp_instance mes_Redis {
 state MASTER
 interface eth0
 garp_master_delay
 smtp_alert
 virtual_router_id
 priority
 nopreempt
 advert_int
 authentication {
 auth_type PASS
 auth_pass
 }
 virtual_ipaddress {
 192.168.1.205
 }
 track_script {
 chk_redis
 }
 notify_master /etc/keepalived/scripts/redis_master.sh
 notify_backup /etc/keepalived/scripts/redis_slave.sh
 notify_fault /etc/keepalived/scripts/redis_fault.sh
 notify_stop /etc/keepalived/scripts/redis_stop.sh
 }

在Redis Master上创建notity_master与notify_backup脚本:

vim /etc/keepalived/scripts/redis_master.sh

#!/bin/bash
REDISCLI="/usr/local/redis/bin/redis-cli"
LOGFILE="/var/log/keepalived-redis-state.log"
echo "[master]" >> $LOGFILE
date >> $LOGFILE
echo "Being master...." >> $LOGFILE >&
echo "Run SLAVEOF cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF 192.168.1.204  >> $LOGFILE  >&
sleep  #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 >&

vim /etc/keepalived/scripts/redis_backup.sh 

#!/bin/bash
REDISCLI="/usr/local/redis/bin/redis-cli"
LOGFILE="/var/log/keepalived-redis-state.log"

echo "[backup]" >> $LOGFILE
date >> $LOGFILE
echo "Being slave...." >> $LOGFILE >&

sleep  #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 192.168.1.204  >> $LOGFILE  >&

在slave上创建配置：

keepalived.conf 如下：

 vim /etc/keepalived/keepalived.conf
 1 vrrp_script chk_redis {
 script "/etc/keepalived/scripts/redis_check.sh"   ###监控脚本
 interval                                         ###监控时间
 }

 vrrp_instance mes_Redis {
 state BACKUP                                      ###设置为BACKUP
 interface eth0                                    ###监控网卡
 garp_master_delay
 smtp_alert
 virtual_router_id
 priority                                       ###比MASTRE权重值低
 nopreempt
 advert_int
 authentication {
 auth_type PASS
 auth_pass                                        ###密码与MASTRE相同
 }
 virtual_ipaddress {
 192.168.1.205                                         ###VIP地址
 }
 track_script {
 chk_redis                                            ###执行上面定义的chk_redis
 }
 notify_master /etc/keepalived/scripts/redis_master.sh
 notify_backup /etc/keepalived/scripts/redis_backup.sh
 notify_fault /etc/keepalived/scripts/redis_fault.sh
 notify_stop /etc/keepalived/scripts/redis_stop.sh
 }

在Redis Slave上创建notity_master与notify_backup脚本：

vim /etc/keepalived/scripts/redis_master.sh
#!/bin/bash
REDISCLI="/usr/local/redis/bin/redis-cli"
LOGFILE="/var/log/keepalived-redis-state.log"
echo "[master]" >> $LOGFILE
date >> $LOGFILE
echo "Being master...." >> $LOGFILE >&
echo "Run SLAVEOF cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF 192.168.1.203  >> $LOGFILE  >&
sleep  #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 >&

vim /etc/keepalived/scripts/redis_backup.sh
#!/bin/bash
REDISCLI="/usr/local/redis/bin/redis-cli"
LOGFILE="/var/log/keepalived-redis-state.log"
echo "[backup]" >> $LOGFILE
date >> $LOGFILE
echo "Being slave...." >> $LOGFILE >&
sleep  #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 192.168.1.203  >> $LOGFILE  >&

在Master和Slave上创建相同监控Redis的脚本:

vim /etc/keepalived/scripts/redis_check.sh
#!/bin/bash
ALIVE=`/opt/redis/bin/redis-cli PING`
if [ "$ALIVE" == "PONG" ]; then
  echo $ALIVE
  exit
else
  echo $ALIVE
  exit
fi

Master与Slave创建如下相同的脚本：

 vim /etc/keepalived/scripts/redis_fault.sh
#!/bin/bash
LOGFILE=/var/log/keepalived-redis-state.log
echo "[fault]" >> $LOGFILE
date >> $LOGFILE

vim /etc/keepalived/scripts/redis_stop.sh
#!/bin/bash
LOGFILE=/var/log/keepalived-redis-state.log
echo "[stop]" >> $LOGFILE
date >> $LOGFILE

给脚本都加上可执行权限：
chmod +x /etc/keepalived/scripts/*.sh

脚本创建完成以后，我们开始按照如下流程进行测试：

启动Master上的Redis

/etc/init.d/redis start

启动Slave上的Redis

/etc/init.d/redis start

启动Master上的Keepalived

/etc/init.d/keepalived start

启动Slave上的Keepalived

/etc/init.d/keepalived start

尝试通过VIP 192.168.1.205 连接Redis:
redis-cli -h 192.168.1.205 INFO

尝试插入一些数据：
redis-cli -h 192.168.1.205 SET Hello Redis
OK
从VIP读取数据
redis-cli -h 192.168.1.205 GET Hello
"Redis"
从Master读取数据
redis-cli -h 192.168.1.205 GET Hello
"Redis"
从Slave读取数据
redis-cli -h 192.168.1.205 GET Hello
"Redis"

下面，模拟故障产生：
将Master上的Redis进程杀死：
killall -9 redis-server
查看Master上的Keepalived日志
tailf /var/log/keepalived-redis-state.log
[fault]
2015年 11月 09日 星期一 20:49:17 CST

同时Slave上的日志显示：
$ tailf /var/log/keepalived-redis-state.log
[master]
2015年 11月 09日 星期一 20:49:19 CST
Being master....
Run SLAVEOF cmd ...
OK Already connected to specified master
Run SLAVEOF NO ONE cmd ...
OK
然后我们可以发现，Slave已经接管服务，并且担任Master的角色了。

daemonize yes                        #启用守护进程
pidfile /var/run/redis.pid
port                             #监听的端口号
tcp-backlog
timeout                             #当客户端闲置多长时间后关闭连接，如果指定为0，表示关闭该功能
tcp-keepalive                         #表示将周期性使用SO_KEEPALIVE检测客户端是否还处于健康状态,单位秒
loglevel notice                        #指定日志记录级别，Redis总共支持四个级别：debug、verbose、notice、warning
logfile "/var/log/redis.log"        #指定日志路径
 syslog-enabled no
 syslog-ident redis
 syslog-facility local0
databases                         #设置数据库的数量
save                              #表示900秒（15分钟）内有1个更改，保存数据到磁盘
save                              #300秒（5分钟）内有10个更改
save                          #60秒内有10000个更改
stop-writes-on-bgsave-error yes        #当持久化出现错误之后，是否继续提供写服务
rdbcompression yes
rdbchecksum yes
dbfilename dump.rdb
dir /usr/local/redis/var/
slaveof 192.168.1.203             #Master的ip地址，这个是master和slave配置文件不一样的地方
slave-serve-stale-data yes
slave-read-only yes
repl-timeout
repl-disable-tcp-nodelay no
slave-priority
maxmemory 4g
appendonly no
appendfilename "appendonly.aof"
appendfsync everysec
no-appendfsync-on-rewrite no
auto-aof-rewrite-percentage
auto-aof-rewrite-min-size 64mb
lua-time-limit
slowlog-log-slower-than
slowlog-max-len
notify-keyspace-events ""
hash-max-ziplist-entries
hash-max-ziplist-value
list-max-ziplist-entries
list-max-ziplist-value
set-max-intset-entries
zset-max-ziplist-entries
zset-max-ziplist-value
activerehashing yes
client-output-buffer-limit normal
client-output-buffer-limit slave 256mb 64mb
client-output-buffer-limit pubsub 32mb 8mb
hz 

redis Slave配置文件如下：

 daemonize yes
 pidfile /var/run/redis.pid
 port 6379
 tcp-backlog 511
 timeout 0
 tcp-keepalive 0
 loglevel notice
 logfile "/var/log/redis.log"
  syslog-enabled no
  syslog-ident redis
  syslog-facility local0
 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/var/
 slaveof 10.10.10.203 6379
 slave-serve-stale-data yes
 slave-read-only yes
 repl-timeout 60
 repl-disable-tcp-nodelay no
 slave-priority 100
 maxmemory 4g
 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

redis_slave.conf

只比redis_slave.con 的配置多slaveof 192.168.1.203 6379，别的都一样.