準備
1.1 準備
keepalived-1.2.22.tar.gz
redis-3.2.1.tar.gz
1.2 說明
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接管服務升級Master，有寫權限，同時關閉主從複製功能；
當 Master 恢復正常, Master降級爲Slave同步數據，開啓主從複製。
1.3 測試服務器信息
Master redis: 192.168.0.4
Slave redis: 192.168.0.5
配置redis服務
- 解壓縮
tar zxf redis-3.2.1.tar.gz
mv redis-3.2.1 /soft/server
cd /soft/server
mv redis-3.2.1 redis - 編譯安裝
cd /soft/server/redis
make && make install - redis配置文件修改
vim redis.conf
...
bind 0.0.0.0 # 修改支持網絡訪問
protected-mode no # 同樣一個安全配置，默認yes是不能網絡訪問的
daemonize yes # 後臺運行redis
slaveof 192.168.0.4 6379 # 指定Master IP，同步（僅從配置） - 配置redis服務啓動腳本
複製代碼
vim /etc/init.d/redis-server
!/usr/bin/env bash
redis start up the redis server daemon
chkconfig: 345 99 99
description: redis service in /etc/init.d/redis
chkconfig --add redis or chkconfig --list redis
service redis start or service redis stop
processname: redis-server
config: /etc/redis.conf
注意不同位置要修改變量
PATH=/usr/local/bin:/sbin:/usr/bin:/bin
REDISPORT=6379
EXEC=/soft/server/redis/src/redis-server
REDIS_CLI=/soft/server/redis/src/redis-cli
PIDFILE=/var/run/redis.pid
CONF="/soft/server/redis/redis.conf"
make sure some dir exist
if [ ! -d /var/lib/redis ] ;then
mkdir -p /var/lib/redis
mkdir -p /var/log/redis
fi
case "$1" in
status)
ps -A|grep redis
;;
start)
if [ -f $PIDFILE ]
then
echo "$PIDFILE exists, process is already running or crashed"
else
echo "Starting Redis server..."
$EXEC $CONF
fi
if [ "$?"="0" ]
then
echo "Redis is running..."
fi
;;
stop)
if [ ! -f $PIDFILE ]
then
echo "$PIDFILE does not exist, process is not running"
else
PID=$(cat $PIDFILE)
echo "Stopping ..."
$REDIS_CLI -p $REDISPORT SHUTDOWN
while [ -x ${PIDFILE} ]
do
echo "Waiting for Redis to shutdown ..."
sleep 1
done
echo "Redis stopped"
fi
;;
restart|force-reload)
${0} stop
${0} start
;;
*)
echo "Usage: /etc/init.d/redis {start|stop|restart|force-reload}" >&2
exit 1
esac
複製代碼
5. 配置開機自啓
chkconfig --add redis-server
chkconfig redis-server on
配置keepalive服務
- 編譯安裝
tar zxf keepalived-1.2.22.tar.gz
cd keepalived-1.2.22
./configure --prefix=/usr/local/keepalived
make && make install - 配置文件設置
複製代碼
拷貝keepalived服務
cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/keepalived
cp /usr/local/keepalived/sbin/keepalived /usr/sbin/keepalived
配置keepalived服務
cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/keepalived
mkdir /etc/keepalived
拷貝配置文件
cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
複製代碼
3. keepalive配置文件
Master節點
複製代碼
! Configuration File for keepalived
vrrp_script chk_redis {
script "/root/scripts/redis_check.sh" ###監控腳本
interval 2 ###監控時間
}
網卡需要注意，使用ifconfig查看一下當前活動網卡
vrrp_instance VI_1 {
state BACKUP ###設置爲BACKUP
nopreempt # 不搶佔MASTER
interface eth0 ###監控網卡
virtual_router_id 51
priority 100 ###權重值
authentication {
auth_type PASS ###加密
auth_pass 1q2w3e ###密碼
}
#設置額外的監控，裏面的任意一個網卡出現問題，都會進入FAULT狀態
track_interface {
eth0
}
track_script {
chk_redis ###執行上面定義的chk_redis
}
virtual_ipaddress {
192.168.0.99 ######VIP
}
notify_master /root/scripts/redis_master.sh
notify_backup /root/scripts/redis_backup.sh
notify_fault /root/scripts/redis_fault.sh
notify_stop /root/scripts/redis_stop.sh
}
複製代碼
Slave節點
複製代碼
! Configuration File for keepalived
vrrp_script chk_redis {
script "/root/scripts/redis_check.sh" ###監控腳本
interval 2 ###監控時間
}
同樣要注意網卡
vrrp_instance VI_1 {
state BACKUP ###設置爲BACKUP
interface eth0 ###監控網卡
virtual_router_id 51
priority 10 ###比MASTRE權重值低
authentication {
auth_type PASS
auth_pass 1q2w3e ###密碼與MASTRE相同
}
#設置額外的監控，裏面的任意一個網卡出現問題，都會進入FAULT狀態
track_interface {
eth0
}
track_script {
chk_redis ###執行上面定義的chk_redis
}
virtual_ipaddress {
192.168.0.99 ####vip
}
notify_master /root/scripts/redis_master.sh
notify_backup /root/scripts/redis_backup.sh
notify_fault /root/scripts/redis_fault.sh
notify_stop /root/scripts/redis_stop.sh
}
複製代碼
4. keepalive腳本
Keepalive 定義的四種狀態腳本說明
當進入Master狀態時會呼叫notify_master
當進入Backup狀態時會呼叫notify_backup
當發現異常情況時進入Fault狀態呼叫notify_fault
當Keepalived程序終止時則呼叫notify_stop
redis_check.sh 檢測redis是否正常腳本，正常則返回PONG，返回代碼0，否則返回代碼1
複製代碼
!/bin/bash
ALIVE=/usr/local/bin/redis-cli PING
if [ "$ALIVE" == "PONG" ]; then
echo $ALIVE
exit 0
else
echo $ALIVE
exit 1
fi
複製代碼
redis_master.sh 我被選入Master時，執行的腳本
複製代碼
!/bin/bash
REDISCLI="/usr/local/bin/redis-cli"
LOGFILE="/var/log/keepalived-redis-state.log"
echo "[master]" >> $LOGFILE
date >> $LOGFILE
echo "Being master...." >> $LOGFILE 2>&1
echo "Run SLAVEOF NO ONE cmd ..." >> $LOGFILE
$REDISCLI SLAVEOF NO ONE >> $LOGFILE 2>&1
複製代碼
redis_fault.sh 當檢測服務不正常是，執行fault腳本
!/bin/bash
LOGFILE=/var/log/keepalived-redis-state.log
echo "[fault]" >> $LOGFILE
date >> $LOGFILE
redis_stop.sh keepalive終止時寫入日誌
!/bin/bash
LOGFILE=/var/log/keepalived-redis-state.log
echo "[stop]" >> $LOGFILE
date >> $LOGFILE
redis_backup.sh 進入slave時執行的腳本
複製代碼
!/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
$REDISCLI SLAVEOF 192.168.0.5 6379 >> $LOGFILE 2>&1 # IP爲之前從redis的IP
複製代碼
這裏backup 腳本主要說明一下，我的keepalive配置了不去搶佔Master，也就是當我Master 宕機後，我master再次起來就是slave，這時就是執行redis_backup的時候了，我去指定我的Master去同步
- 配置開機自啓
chkconfig --add keepalived
chkconfig keepalived on
測試 vip 192.168.75.200 連接的是主節點128
Replication
role:master
connected_slaves:1
slave0:ip=192.168.75.131,port=6379,state=online,offset=1569,lag=1
master_repl_offset:1569
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:2
repl_backlog_histlen:1568
測試是否IP漂移到從節點，同時131從節點變主節點提供服務。
128 停止redis服務，模擬主節點掛掉。
systemctl stop redis
131 變主節點，提供讀寫服務
info
Replication
role:master
connected_slaves:0
master_repl_offset:0
repl_backlog_active:0
repl_backlog_size:1048576
repl_backlog_first_byte_offset:2
repl_backlog_histlen:513
開啓128之前的主節點，這時128變爲從節點提供讀的服務。同時會把131的數據同步到128。
systemctl start redis
128變成了從節點了。
role:slave
master_host:192.168.75.131
master_port:6379
master_link_status:up
master_last_io_seconds_ago:2
master_sync_in_progress:0
slave_repl_offset:43
slave_priority:100
slave_read_only:1
總結
如果服務器資源不夠的話，用keepalived就行了。兩個節點就行了。sentinel是redis官網推薦的方案，需要的服務器比較多，最少三臺，因爲它用了節點仲裁原理來選master。