vivion32 发表于 2018-11-5 07:12:06

redis+keepalived 主从热备 实例

  应用环境:
  操作系统:centos 5.6 x64
  redis版本:redis-2.8.10.tar.gz
  keepalived版本:keepalived-1.2.12.tar.gz
  redismaster : 192.168.101.50
  redis   salve : 192.168.101.51

  原理:如果返回时间超过keepalived vrrp_scripts的超时时间,keepalived会进入faild 状态,从而触发keepalived集群开始进行vip漂移
  当 Master 挂掉,Slave 正常时, Slave接管服务,有写权限,同时关闭主从复制功能;
  当 Master 恢复正常,则从Slave同步数据,同步数据之后关闭主从复制功能,恢复Master身份,同时Slave等待Master同步数据完成之后,恢复Slave身份。
  部署安装:
  1、在mastersalve 上编译安装依赖包
  yum -y install gcc gcc+ gcc-c++ openssl openssl-devel pcre pcre-devel
  软件包download:
  redis-2.8.10.tar.gz               wget http://www.915c.com/softfile/redis-2.8.10.tar.gz
  keepalived-1.2.12.tar.gz      wget http://www.keepalived.org/software/keepalived-1.2.12.tar.gz
  gperftools-2.1.tar.gz            wget http://down.51cto.com/data/1332597
  libunwind-1.1.tar.gz      wget http://down.51cto.com/data/1332597
  2、编译安装 (master salve安装方法一致)
  # tar xflibunwind-1.1.tar.gz
  # cd libunwind-1.1
  # CFLAGS=-fPIC ./configure
  # make CFLAGS=-fPIC
  # make CFLAGS=-fPIC install
  # tar xf gperftools-2.1.tar.gz
  # cd gperftools-2.1
  # /configure--disable-cpu-profiler --disable-heap-profiler --disable-heap-checker --disable-debugalloc --enable-minimal
  #make && make install
  # echo "/usr/local/lib" > /etc/ld.so.conf.d/usr_local_lib.conf
  # /sbin/ldconfig
  # cd /usr/local/lib
  # ln -sv libtcmalloc_minimal.so.4.1.2 libtcmalloc.so
  # tar xf redis-2.8.10.tar.gz
  # cd redis2.8.10
  # mkdir -p /opt/redis
  # make PREFIX=/opt/redis USE_TCMALLOC=yes FORCE_LIBC_MALLOC=yes install
  3、配置redis
  创建配置文件夹以及文件
  mkdir -p /opt/redis/etc
  mkdir -p /opt/redis/run
  mkdir -p /opt/redis/data/6379
  mkdir -p /opt/redis/log
  cp /redis的解压路径 /redis.conf /opt/redis/etc/redis.conf
  cp /opt/redis/etc/redis.conf /opt/redis/etc/redis_6379.conf
  修改配置文件:
  vim /opt/redis/etc/redis_6379.conf
  daemonize yes
  pidfile /opt/redis/run/redis_6379.pid
  dir /opt/redis/data/6379
  logfile /opt/redis/log/redis_6379.log
  创建服务管理脚本
  vim /etc/init.d/redis
  #!/bin/sh
  PATH="/opt/redis/bin:$PATH"
  EXEC="/opt/redis/bin/redis-server"
  CLIEXEC="/opt/redis/bin/redis-cli"
  PIDFILE="/opt/redis/run/redis_6379.pid"
  CONF="/opt/redis/etc/redis_6379.conf"
  REDISPORT="6379"
  case "$1" in
  start)
  if [ -f $$PIDFILE ]
  then
  echo "$PIDFILE exists, process is already running or crashed."
  else
  echo "Starting Redis server..."
  $EXEC $CONF
  fi
  ;;
  stop)
  if [ ! -f $PIDFILE ]
  then
  echo "$PIDFILE does not exist, process is not running."
  else
  PID=$(cat $PIDFILE)
  echo "Stopping ..."
  $CLIEXEC -p $REDISPORT shutdown
  while [ -x /proc/${PID} ]
  do
  echo "Waiting for Redis to shutdown ..."
  sleep 1
  done
  echo "Redis stopped."
  fi
  ;;
  *)
  echo "Usage: $0 {start|stop}" >&2
  exit 1
  ;;
  esac
  授权 chmod +x /etc/init.d/redis
  vim /etc/sysctl.conf
  在最后添加以下节点:
  vm.overcommit_memory = 1
  sysctl -p
  redis 就安装完毕了
  4、启动测试
  启动redis 服务
  # /etc/init.d/redis start
  #ps -aux |grep redis查看进程
  打开防火墙6379端口
  5、测试redis的主从复制
  # /opt/redis/bin/redis-cli -p 6379 set test1 www.baidu.com       \\通过masterset设置一个key键为test1 写入values值www.baidu.com

  返回一个ok
  在master本地测试取test1 的key值
  # /opt/redis/bin/redis-cli -p 6379 get test1

  在salve端测试读取master写入的文件test1
  # /opt/redis/bin/redis-cli -p 6379 get test1

  6、安装keepalived
  # tar xf 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
  7、首先在master上创建如下配置
  # mkdir -p /etc/keepalived
  # vim /etc/keepalived/keepalived.conf
  vrrp_script chk_redis {
  script "/etc/keepalived/scripts/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 51
  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 {
  192.168.101.52                     ###VIP
  }
  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 Master上创建redis_master脚本
  # vim /etc/keepalived/scripts/redis_master.sh
  #!/bin/bash
  REDISCLI="/opt/redis/bin/redis-cli"
  LOGFILE="/var/log/keepalived-redis-state.log"
  echo "" >> $LOGFILE
  date >> $LOGFILE
  echo "Being master...." >> $LOGFILE 2>&1
  echo "Run SLAVEOF cmd ..." >> $LOGFILE
  $REDISCLI SLAVEOF 192.168.101.51(slave) 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
  在Redis Master上创建redis_backup脚本
  # vim /etc/keepalived/scripts/redis_backup.sh
  #!/bin/bash
  REDISCLI="/opt/redis/bin/redis-cli"
  LOGFILE="/var/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 192.168.101.51(slave)6379 >> $LOGFILE2>&1
  在slave上创建如下文件:
  # vim /etc/keepalived/keepalived.conf
  vrrp_script chk_redis {
  script "/etc/keepalived/scripts/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 51
  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 {
  192.168.101.52                         ###VIP
  }
  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 salve上创建redis_master脚本
  vim /etc/keepalived/scripts/redis_master.sh
  #!/bin/bash
  REDISCLI="/opt/redis/bin/redis-cli"
  LOGFILE="/var/log/keepalived-redis-state.log"
  echo "" >> $LOGFILE
  date >> $LOGFILE
  echo "Being master...." >> $LOGFILE 2>&1
  echo "Run SLAVEOF cmd ..." >> $LOGFILE
  $REDISCLI SLAVEOF 192.168.101.50(master) 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
  在Redis Master上创建redis_backup脚本
  # vim /etc/keepalived/scripts/redis_backup.sh
  #!/bin/bash
  REDISCLI="/opt/redis/bin/redis-cli"
  LOGFILE="/var/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 192.168.101.506379 >> $LOGFILE2>&1
  以下脚本分别在master和slave上创建
  #mkdir /etc/keepalived/scripts
  #vim /etc/keepalived/scripts/redis_check.sh
  #!/bin/bash
  ALIVE=`/opt/redis/bin/redis-cli PING`
  if [ "$ALIVE" == "PONG" ]; then
  echo $ALIVE
  exit 0
  else
  echo $ALIVE
  exit 1
  fi
  # vim /etc/keepalived/scripts/redis_fault.sh
  #!/bin/bash
  LOGFILE=/var/log/keepalived-redis-state.log
  echo "" >> $LOGFILE
  date >> $LOGFILE
  #vim /etc/keepalived/scripts/redis_stop.sh
  #!/bin/bash
  LOGFILE=/var/log/keepalived-redis-state.log
  echo "" >> $LOGFILE
  date >> $LOGFILE
  授执行权chmod +x /etc/keepalived/scripts/*.sh
  8、测试高可用性。
  1、启动master和slave节点上keepalived
  # /etc/init.d/keepalived start
  启动 keepalived:                                          [确定]
  # /etc/init.d/keepalived start
  Starting keepalived:                                       
  查看master的网络地址 vip地址的绑定状态

  查看slave

  9、测试vip连接redis
  # /opt/redis/bin/redis-cli -h 192.168.101.52 INFO |grep -A8 Replication

  # /opt/redis/bin/redis-cli -h 192.168.101.52 INFO |grep -A8 Replication

  10、测试插入和取出key

  # /opt/redis/bin/redis-cli -h 192.168.101.52 set oneday www.baidu.com
  OK
  You have new mail in /var/spool/mail/root
  # /opt/redis/bin/redis-cli -h 192.168.101.52 get oneday
  "www.baidu.com"
  # /opt/redis/bin/redis-cli -h 192.168.101.50 get oneday
  "www.baidu.com"
  # /opt/redis/bin/redis-cli -h 192.168.101.51 get oneday
  "www.baidu.com"
  11、测试vip漂移和redis高可用
  关闭master节点的redis服务
  # /etc/init.d/redis stop
  Stopping ...
  Redis stopped.
  查看vip 地址 slave变化状态
  master

  slave


  12、测试故障恢复redis master恢复
  启动master节点的redis 服务器,观察变化情况


  slave节点

  slave自动切换为slave节点服务
  到此测试完成。
  备注:
  以上方案存在不足之处:1、当master节点故障后,虽然slave节点接管了服务,但是毕竟slave没有写入的权限,导致slave需要写入文件的时候报错
  # /opt/redis/bin/redis-cli -h 192.168.101.52 set twoday www.sina.net
  (error) READONLY You can't write against a read only slave.
  这个时候,如果是强制将slave节点手打或者脚本升级为master节点,则出现当master恢复时,原master与slave已经隔离,不能完成数据同步。
  2、通过哨兵Redis Sentinel 监控master slave 监听可以实现当master出故障时,slave可以自动切换为master并接管工作,但当master端恢复后,会一直停留在slave状态,不会再抢占成为master节点。
  3、抛出一个问题:假如master 是一台服务器性能比较高,而slave是一台性能较差的服务器,如何做到,当master节点故障时,slave自动切换为master并且有读写的权限,当原master节点恢复后,自动抢占成为master节点?

页: [1]
查看完整版本: redis+keepalived 主从热备 实例