Redis + Keepalived主從叢集的搭建及容錯移轉

Redis + Keepalived主從叢集的搭建及容錯移轉 設計思路： 當 Master 與 Slave 均運作正常時, Master負責服務，Slave負責Standby； 當 Master 掛掉，Slave 正常時, Slave接管服務，同時關閉主從複製功能； 當 Master 恢複正常，則從Slave同步資料，同步資料之後關閉主從複製功能，恢複Master身份，於此同時Slave等待Master同步資料完成之後，恢複Slave身份。 然後依次迴圈。 注意事項:

    需要在Master與Slave上都開啟本地化策略，否則在互相自動切換的過程中，未開啟本地化的一方會將另一方的資料清空，造成資料完全丟失。 環境準備

叢集可以是單台機器的不同連接埠，也可以是多台機器，通常實際應用是，多台機器。假設目前已經安裝好了2台機器，IP和連接埠分別是

主Redis伺服器IP：192.168.1.148主Redis伺服器連接埠號碼：6379從Redis伺服器IP：192.168.1.158從Redis伺服器連接埠號碼：6379

設定一個虛擬IP

192.168.1.200

進入root使用者

xiaoyao@xiaoyao-virtual-machine:~$ su密碼： root@xiaoyao-virtual-machine:/home/xiaoyao# 

主從兩個機器上分別安裝Keepalived

root@xiaoyao-virtual-machine:/home/xiaoyao# apt-get install keepalived

主從伺服器分別修改hosts檔案

root@xiaoyao-virtual-machine:/home/xiaoyao# vim /etc/hosts在檔案末尾添加192.168.1.148 redis148192.168.1.158 redis158

主伺服器建立設定檔

root@xiaoyao-virtual-machine:/home/xiaoyao# vim /etc/keepalived/keepalived.conf

配置內容：

! Configuration File for keepalivedglobal_defs {    router_id redis148}vrrp_script chk_redis {     script "/etc/keepalived/scripts/redis_check.sh 127.0.0.1 6379"     interval 2     timeout 2    fall 3}vrrp_instance redis {    state MASTER # master set to SLAVE also    interface eth0      virtual_router_id 50     priority  150           nopreempt # no seize,must add    advert_int 1    authentication {   #all node must same        auth_type PASS        auth_pass 1111    }       virtual_ipaddress {          192.168.1.200/24    }    track_script {         chk_redis     }     notify_master "/etc/keepalived/scripts/redis_master.sh 127.0.0.1 192.168.1.158 6379"    notify_backup "/etc/keepalived/scripts/redis_backup.sh 127.0.0.1 192.168.1.158 6379"    notify_fault /etc/keepalived/scripts/redis_fault.sh     notify_stop /etc/keepalived/scripts/redis_stop.sh }

這裡可能會出錯，一般虛擬機器設定成：interface eth0，但是有的機器可能是em1，這個要根據情況來配置，否則建立虛擬IP會失敗。
舉個例子：
查看IP後是下面的樣子

root@ubuntu:/etc/init.d# cat /etc/network/interfaces# This file describes the network interfaces available on your system# and how to activate them. For more information, see interfaces(5).# The loopback network interfaceauto em1iface em1 inet staticaddress 192.168.0.33netmask 255.255.255.0gateway 192.168.0.1

那麼就應該配置成

interface em1

從伺服器建立設定檔

root@xiaoyao-virtual-machine:/home/xiaoyao# vim /etc/keepalived/keepalived.conf

配置內容：

! Configuration File for keepalivedglobal_defs {   router_id redis158}vrrp_script chk_redis {      script "/etc/keepalived/scripts/redis_check.sh 127.0.0.1 6379"      interval 2     timeout 2     fall 3}vrrp_instance redis {    state BACKUP       interface eth0       virtual_router_id 50      priority  100           advert_int 1    authentication {   #all node must same        auth_type PASS        auth_pass 1111    }       virtual_ipaddress {     192.168.1.200/24    }    track_script {          chk_redis     }     notify_master "/etc/keepalived/scripts/redis_master.sh 127.0.0.1 192.168.1.148 6379"    notify_backup "/etc/keepalived/scripts/redis_backup.sh 127.0.0.1 192.168.1.148 6379"    notify_fault /etc/keepalived/scripts/redis_fault.sh     notify_stop /etc/keepalived/scripts/redis_stop.sh }

在主伺服器和從伺服器上分別建立監控Redis的指令碼

root@xiaoyao-virtual-machine:/home/xiaoyao# mkdir /etc/keepalived/scriptsroot@xiaoyao-virtual-machine:/home/xiaoyao# vim /etc/keepalived/scripts/redis_check.sh

指令碼內容：

#!/bin/bash ALIVE=`/usr/local/bin/redis-cli -h $1 -p $2 PING` LOGFILE="/var/log/keepalived-redis-check.log" echo "[CHECK]" >> $LOGFILEdate >> $LOGFILEif [ $ALIVE == "PONG" ]; then :    echo "Success: redis-cli -h $1 -p $2 PING $ALIVE" >> $LOGFILE 2>&1   exit 0 else    echo "Failed:redis-cli -h $1 -p $2 PING $ALIVE " >> $LOGFILE 2>&1   exit 1 fi 

Keepalived在轉換狀態時會根據狀態來呼叫： 當進入Master狀態時會呼叫redis_master 當進入Backup狀態時會呼叫redis_backup 當發現異常情況時進入Fault狀態呼叫redis_fault 當Keepalived程式終止時則呼叫redis_stop

下面在主從伺服器分別建立下列指令碼 在主伺服器上建立redis_master指令碼

root@xiaoyao-virtual-machine:/home/xiaoyao# vim /etc/keepalived/scripts/redis_master.sh

指令碼內容

#!/bin/bash REDISCLI="/usr/local/bin/redis-cli -h $1 -p $3" LOGFILE="/var/log/keepalived-redis-state.log" echo "[master]" >> $LOGFILE date >> $LOGFILE echo "Being master...." >> $LOGFILE 2>&1  echo "Run MASTER cmd ..." >> $LOGFILE 2>&1$REDISCLI SLAVEOF $2 $3 >> $LOGFILE  sleep 10 #delay 10 s wait data async cancel syncecho "Run SLAVEOF NO ONE cmd ..." >> $LOGFILE$REDISCLI SLAVEOF NO ONE >> $LOGFILE 2>&1

在主伺服器上建立redis_backup指令碼

root@xiaoyao-virtual-machine:/home/xiaoyao# vim /etc/keepalived/scripts/redis_backup.sh

指令碼內容

#!/bin/bash REDISCLI="/usr/local/bin/redis-cli" 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 15 #delay 15 s wait data sync exchange role 

在主伺服器上建立redis_fault指令碼

root@xiaoyao-virtual-machine:/home/xiaoyao# vim /etc/keepalived/scripts/redis_fault.sh

指令碼內容

#!/bin/bash LOGFILE=/var/log/keepalived-redis-state.log echo "[fault]" >> $LOGFILEdate >> $LOGFILE 

在主伺服器上建立redis_stop指令碼

root@xiaoyao-virtual-machine:/home/xiaoyao# vim /etc/keepalived/scripts/redis_stop.sh

指令碼內容

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

在從伺服器上建立redis_master指令碼

root@xiaoyao-virtual-machine:/home/xiaoyao# vim /etc/keepalived/scripts/redis_master.sh

指令碼內容

#!/bin/bash REDISCLI="/usr/local/bin/redis-cli -h $1 -p $3" 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 roleecho "Run SLAVEOF NO ONE cmd ..." >> $LOGFILE$REDISCLI SLAVEOF NO ONE >> $LOGFILE 2>&1 

在從伺服器上建立redis_backup指令碼

root@xiaoyao-virtual-machine:/home/xiaoyao# vim /etc/keepalived/scripts/redis_backup.sh

指令碼內容

#!/bin/bash REDISCLI="/usr/local/bin/redis-cli" 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 100 #delay 10 s wait data async cancel sync exit(0)

在從伺服器上建立redis_fault指令碼

root@xiaoyao-virtual-machine:/home/xiaoyao# vim /etc/keepalived/scripts/redis_fault.sh

指令碼內容

#!/bin/bash LOGFILE=/var/log/keepalived-redis-state.log echo "[fault]" >> $LOGFILEdate >> $LOGFILE 

在從伺服器上建立redis_stop指令碼

root@xiaoyao-virtual-machine:/home/xiaoyao# vim /etc/keepalived/scripts/redis_stop.sh

指令碼內容

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

主伺服器和從伺服器分別給指令碼添加可執行許可權

root@xiaoyao-virtual-machine:/home/xiaoyao# chmod +x /etc/keepalived/scripts/*.sh

啟動服務測試

啟動主伺服器上的Redis

root@xiaoyao-virtual-machine:/home/xiaoyao# service redis start

啟動從伺服器上的Redis

root@xiaoyao-virtual-machine:/home/xiaoyao# service redis start

啟動主伺服器上的Keepalived

root@xiaoyao-virtual-machine:/home/xiaoyao# /etc/init.d/keepalived start

啟動從伺服器上的Keepalived

root@xiaoyao-virtual-machine:/home/xiaoyao# /etc/init.d/keepalived start

通過虛擬ip串連Redis

root@xiaoyao-virtual-machine:/home/xiaoyao# redis-cli -h 192.168.1.200 INFO # Replicationrole:masterconnected_slaves:1slave0:ip=192.168.1.158,port=6379,state=online,offset=15,lag=1master_repl_offset:15repl_backlog_active:1repl_backlog_size:1048576repl_backlog_first_byte_offset:2repl_backlog_histlen:14

通過虛擬ip插入一條資料

root@xiaoyao-virtual-machine:/home/xiaoyao# redis-cli -h 192.168.1.200 SET Hello Redis

主從伺服器均能讀到此條資料

root@xiaoyao-virtual-machine:/home/xiaoyao# redis-cli -h 192.168.1.200 GET Helloroot@xiaoyao-virtual-machine:/home/xiaoyao# redis-cli -h 192.168.1.148 GET Helloroot@xiaoyao-virtual-machine:/home/xiaoyao# redis-cli -h 192.168.1.158 GET Hello

在主伺服器上殺死redis進程

root@xiaoyao-virtual-machine:/home/xiaoyao# killall -9 redis-server

查看主伺服器上的Keepalived日誌

root@xiaoyao-virtual-machine:/home/xiaoyao# tailf /var/log/keepalived-redis-state.log

查看從伺服器上的Keepalived日誌

root@xiaoyao-virtual-machine:/home/xiaoyao# tailf /var/log/keepalived-redis-state.log

查看從伺服器上的資訊

root@xiaoyao-virtual-machine:/home/xiaoyao# redis-cli -h 192.168.1.158 INFO# Replicationrole:masterconnected_slaves:0master_repl_offset:0repl_backlog_active:0repl_backlog_size:1048576repl_backlog_first_byte_offset:2repl_backlog_histlen:0