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通过Keepalived+HAProxy实现MySQL高可用负载均衡配置的教程介绍

2016-03-10 09:18:23 来源:www.45fan.com 【

通过Keepalived+HAProxy实现MySQL高可用负载均衡配置的教程介绍

Keepalived

由于在生产环境使用了mysqlcluster,需要实现高可用负载均衡,这里提供了keepalived+haproxy来实现.

keepalived主要功能是实现真实机器的故障隔离及负载均衡器间的失败切换.可在第3,4,5层交换.它通过VRRPv2(Virtual Router Redundancy Protocol) stack实现的.

Layer3:Keepalived会定期向服务器群中的服务器.发送一个ICMP的数据包(既我们平时用的Ping程序),如果发现某台服务的IP地址没有激活,Keepalived便报告这台服务器失效,并将它从服务器群中剔除,这种情况的典型例子是某台服务器被非法关机。Layer3的方式是以服务器的IP地址是否有效作为服务器工作正常与否的标准。

Layer4:主要以TCP端口的状态来决定服务器工作正常与否。如web server的服务端口一般是80,如果Keepalived检测到80端口没有启动,则Keepalived将把这台服务器从服务器群中剔除。

Layer5:在网络上占用的带宽也要大一些。Keepalived将根据用户的设定检查服务器程序的运行是否正常,如果与用户的设定不相符,则Keepalived将把服务器从服务器群中剔除。

Software Design

通过Keepalived+HAProxy实现MySQL高可用负载均衡配置的教程介绍

keepalived启动后会有单个进程

8352 ?  Ss  0:00 /usr/sbin/keepalived
8353 ?  S  0:00 \_ /usr/sbin/keepalived
8356 ?  S  0:01 \_ /usr/sbin/keepalived

父进程:内存管理,子进程管理等等

子进程:VRRP子进程

子进程:Healthchecking 子进程
实例

2台mysqlcluster 10.1.6.203 master 10.1.6.205 backup

vip 10.1.6.173

目的访问10.1.6.173 3366端口 分别轮询通过haproxy转发到10.1.6.203 3306 和10.1.6.205 3306

mysqlcluster搭建参照之前博客,这里在2台机上安装keepalived

root@10.1.6.203:~# apt-get install keepalived
root@10.1.6.203:~# cat /etc/keepalived/keepalived.conf 
vrrp_script chk_haproxy {
  script "killall -0 haproxy" # verify the pid existance
  interval 2     # check every 2 seconds
  weight -2     # add 2 points of prio if OK
}
 
vrrp_instance VI_1 {
  interface eth1    # interface to monitor
  state MASTER     
  virtual_router_id 51   # Assign one ID for this route
  priority 101     # 101 on master, 100 on backup
  nopreempt
  debug
 
  virtual_ipaddress {
    10.1.6.173
  }
 
  track_script {  #注意大括号空格
    chk_haproxy
  }
 
  notify_master /etc/keepalived/scripts/start_haproxy.sh #表示当切换到master状态时,要执行的脚本
  notify_fault /etc/keepalived/scripts/stop_keepalived.sh #故障时执行的脚本
  notify_stop /etc/keepalived/scripts/stop_haproxy.sh #keepalived停止运行前运行notify_stop指定的脚本 }

VRRPD配置包括三个类:

  • VRRP同步组(synchroization group)
  • VRRP实例(VRRP Instance)
  • VRRP脚本

这里使用了 VRRP实例, VRRP脚本

注意配置选项:

stat:指定instance(Initial)的初始状态,就是说在配置好后,这台服务器的初始状态就是这里指定的,但这里指定的不算,还是得要通过竞选通过优先级来确定,里如果这里设置为master,但如若他的优先级不及另外一台,那么这台在发送通告时,会发送自己的优先级,另外一台发现优先级不如自己的高,那么他会就回抢占为master

  • interface:实例绑定的网卡,因为在配置虚拟IP的时候必须是在已有的网卡上添加的
  • priority 101:设置本节点的优先级,优先级高的为master
  • debug:debug级别
  • nopreempt:设置为不抢占
vrrp_script chk_haproxy {
  script "killall -0 haproxy" # verify the pid existance
  interval 2     # check every 2 seconds 脚本执行间隔
  weight -2     # add 2 points of prio if OK 脚本结果导致的优先级变更:2表示优先级+2;-2则表示优先级-2
}

然后在实例(vrrp_instance)里面引用,有点类似脚本里面的函数引用一样:先定义,后引用函数名

  track_script {
    chk_haproxy
  }

注意:VRRP脚本(vrrp_script)和VRRP实例(vrrp_instance)属于同一个级别

root@10.1.6.203:scripts# cat start_haproxy.sh 
#!/bin/bash
 
sleep 5
get=`ip addr |grep 10.1.6.173 |wc -l`
echo $get >> /etc/keepalived/scripts/start_ha.log
 
if [ $get -eq 1 ]
then
  echo "`date +%c` success to get vip" >> /etc/keepalived/scripts/start_ha.log
  /usr/local/sbin/haproxy -f /etc/haproxy/haproxy.cfg
else
  echo "`date +%c` can not get vip" >> /etc/keepalived/scripts/start_ha.log
fi
root@10.1.6.203:scripts# cat stop_keepalived.sh 
#!/bin/bash
 
pid=`pidof keepalived`
if [ $pid == "" ]
then
 echo "`date +%c` no keepalived process id" >> /etc/keepalived/scripts/stop_keep.log
else
 echo "`date +%c` will stop keepalived " >> /etc/keepalived/scripts/stop_keep.log
 /etc/init.d/keepalived stop
fi
 
/etc/init.d/keepalived stop
 
root@10.1.6.203:scripts# cat stop_haproxy.sh 
#!/bin/bash
 
pid=`pidof haproxy`
echo "`date +%c` stop haproxy" >> /etc/keepalived/scripts/stop_ha.log
kill -9 $pid

同理配置10.1.6.205

root@10.1.6.205:~# cat /etc/keepalived/keepalived.conf 
vrrp_script chk_haproxy {
 script "killall -0 haproxy" # verify the pid existance
 interval 2     # check every 2 seconds
 weight 2      # add 2 points of prio if OK
}
 
vrrp_instance VI_1 {
 interface eth1    # interface to monitor
 state BACKUP
 virtual_router_id 51   # Assign one ID for this route
 priority 100     # 101 on master, 100 on backup
 virtual_ipaddress {
  10.1.6.173
 }
 
 track_script {
  chk_haproxy
 }
 
notify_master /etc/keepalived/scripts/start_haproxy.sh
notify_fault /etc/keepalived/scripts/stop_keepalived.sh
notify_stop /etc/keepalived/scripts/stop_haproxy.sh
 
}

HAProxy

下面再介绍下haproxy

HAProxy是一款基于TCP(第四层)和HTTP(第七层)应用的代理软件,它也可作为负载均衡器.可以支持数以万计的并发连接.同时可以保护服务器不暴露到网络上,通过端口映射.它还自带监控服务器状态的页面.

安装haproxy

wget -O/tmp/haproxy-1.4.22.tar.gz http://haproxy.1wt.eu/download/1.4/src/haproxy-1.4.22.tar.gz
tar xvfz /tmp/haproxy-1.4.22.tar.gz -C /tmp/
cd /tmp/haproxy-1.4.22
make TARGET=linux26
make install

haproxy需要对每一个mysqlcluster服务器进行健康检查

1.在2台主机分别配置haproxy.cfg

root@10.1.6.203:scripts# cat /etc/haproxy/haproxy.cfg 
global
  maxconn 51200 #默认最大连接数 
  #uid 99
  #gid 99
  daemon  #以后台形式运行haproxy
  #quiet
  nbproc 1  #进程数量(可以设置多个进程提高性能) 
  pidfile /etc/haproxy/haproxy.pid #haproxy的pid存放路径,启动进程的用户必须有权限访问此文件 
 
defaults
  mode tcp   #所处理的类别 (#7层 http;4层tcp ) 
  option redispatch #serverId对应的服务器挂掉后,强制定向到其他健康的服务器 
  option abortonclose #当服务器负载很高的时候,自动结束掉当前队列处理比较久的连接 
  timeout connect 5000s #连接超时
  timeout client 50000s #客户端超时
  timeout server 50000s #服务器超时
  log 127.0.0.1 local0 #错误日志记录
  balance roundrobin #默认的负载均衡的方式,轮询方式 
 
listen proxy
  bind 10.1.6.173:3366 #监听端口 
  mode tcp    #http的7层模式
  option httpchk  #心跳检测的文件
  server db1 10.1.6.203:3306 weight 1 check port 9222 inter 12000 rise 3 fall 3  #服务器定义,check inter 12000是检测心跳频率 rise 3是3次正确认为服务器可用, fall 3是3次失败认为服务器不可用,weight代表权重 
  server db2 10.1.6.205:3306 weight 1 check port 9222 inter 12000 rise 3 fall 3
 
listen haproxy_stats
  mode http
  bind 10.1.6.173:8888
  option httplog
  stats refresh 5s 
  stats uri /status #网站健康检测URL,用来检测HAProxy管理的网站是否可以用,正常返回200,不正常返回503 
  stats realm Haproxy Manager
  stats auth admin:p@a1SZs24 #账号密码

root@10.1.6.205:~$ cat /etc/haproxy/haproxy.cfg 
global
  maxconn 51200
  #uid 99
  #gid 99
  daemon
  #quiet
  nbproc 1
  pidfile /etc/haproxy/haproxy.pid
 
defaults
  mode tcp
  option redispatch 
  option abortonclose
  timeout connect 5000s
  timeout client 50000s
  timeout server 50000s
  log 127.0.0.1 local0
  balance roundrobin 
 
listen proxy
  bind 10.1.6.173:3366
  mode tcp
  option httpchk
  server db1 10.1.6.203:3306 weight 1 check port 9222 inter 12000 rise 3 fall 3
  server db2 10.1.6.205:3306 weight 1 check port 9222 inter 12000 rise 3 fall 3
 
listen haproxy_stats
  mode http
  bind 10.1.6.173:8888
  option httplog
  stats refresh 5s 
  stats uri /status 
  stats realm Haproxy Manager
  stats auth admin:p@a1SZs24

2.安装xinetd

root@10.1.6.203:~# apt-get install xinetd

3.在每个节点添加xinetd服务脚本和mysqlchk端口号

root@10.1.6.203:~# vim /etc/xinetd.d/mysqlchk 
# default: on
# description: mysqlchk
service mysqlchk     #需要在servive定义
{
  flags   = REUSE
  socket_type  = stream
  port   = 9222
  wait   = no
  user   = nobody
  server   = /opt/mysqlchk 
  log_on_failure += USERID
  disable   = no
  per_source  = UNLIMITED
  bind   = 10.1.6.173
}
 
root@10.1.6.203:~# vim /etc/services 
mysqlchk  9222/tcp      # mysqlchk

4.编写mysqlchk监控服务脚本

root@10.1.6.203:~# ls -l /opt/mysqlchk 
-rwxr--r-- 1 nobody root 1994 2013-09-17 11:27 /opt/mysqlchk
root@10.1.6.203:~# cat /opt/mysqlchk 
#!/bin/bash
#
# This script checks if a mysql server is healthy running on localhost. It will
# return:
# "HTTP/1.x 200 OK\r" (if mysql is running smoothly)
# - OR -
# "HTTP/1.x 500 Internal Server Error\r" (else)
#
# The purpose of this script is make haproxy capable of monitoring mysql properly
#
 
MYSQL_HOST="localhost"
MYSQL_SOCKET="/var/run/mysqld/mysqld.sock"
MYSQL_USERNAME="mysqlchkusr"  #该账户密码需要在mysql里添加
MYSQL_PASSWORD="secret"
MYSQL_OPTS="-N -q -A"
TMP_FILE="/dev/shm/mysqlchk.$$.out"
ERR_FILE="/dev/shm/mysqlchk.$$.err"
FORCE_FAIL="/dev/shm/proxyoff"
MYSQL_BIN="/opt/mysqlcluster/mysql-cluster-gpl-7.2.6-linux2.6-x86_64/bin/mysql"
CHECK_QUERY="select 1"
 
preflight_check()
{
 for I in "$TMP_FILE" "$ERR_FILE"; do
  if [ -f "$I" ]; then
   if [ ! -w $I ]; then
    echo -e "HTTP/1.1 503 Service Unavailable\r\n"
    echo -e "Content-Type: Content-Type: text/plain\r\n"
    echo -e "\r\n"
    echo -e "Cannot write to $I\r\n"
    echo -e "\r\n"
    exit 1
   fi
  fi
 done
}
 
return_ok()
{
 echo -e "HTTP/1.1 200 OK\r\n"
 echo -e "Content-Type: text/html\r\n"
 echo -e "Content-Length: 43\r\n"
 echo -e "\r\n"
 echo -e "<html><body>MySQL is running.</body></html>\r\n"
 echo -e "\r\n"
 rm $ERR_FILE $TMP_FILE
 exit 0
}
return_fail()
{
 echo -e "HTTP/1.1 503 Service Unavailable\r\n"
 echo -e "Content-Type: text/html\r\n"
 echo -e "Content-Length: 42\r\n"
 echo -e "\r\n"
 echo -e "<html><body>MySQL is *down*.</body></html>\r\n"
 sed -e 's/\n$/\r\n/' $ERR_FILE
 echo -e "\r\n"
 rm $ERR_FILE $TMP_FILE
 exit 1
}
preflight_check
if [ -f "$FORCE_FAIL" ]; then
  echo "$FORCE_FAIL found" > $ERR_FILE
  return_fail;
fi
$MYSQL_BIN $MYSQL_OPTS --host=$MYSQL_HOST --socket=$MYSQL_SOCKET --user=$MYSQL_USERNAME --password=$MYSQL_PASSWORD -e "$CHECK_QUERY" > $TMP_FILE 2> $ERR_FILE
if [ $? -ne 0 ]; then
  return_fail;
fi
return_ok;

测试

2个节点开启keepalived(主节点会获得vip,自动拉起haproxy),xinetd

root@10.1.6.203:~# ip add
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN 
 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
 inet 127.0.0.1/8 scope host lo
2: eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN qlen 1000
 link/ether 00:26:b9:36:0f:81 brd ff:ff:ff:ff:ff:ff
 inet 211.151.105.186/26 brd 211.151.105.191 scope global eth0
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
 link/ether 00:26:b9:36:0f:83 brd ff:ff:ff:ff:ff:ff
 inet 10.1.6.203/24 brd 10.1.6.255 scope global eth1
 inet 10.1.6.173/32 scope global eth1
4: eth2: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000
 link/ether 00:26:b9:36:0f:85 brd ff:ff:ff:ff:ff:ff
5: eth3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000
 link/ether 00:26:b9:36:0f:87 brd ff:ff:ff:ff:ff:ff
root@10.1.6.203:~# netstat -tunlp | grep ha
tcp  0  0 10.1.6.173:3366  0.0.0.0:*    LISTEN  1042/haproxy 
tcp  0  0 10.1.6.203:8888  0.0.0.0:*    LISTEN  1042/haproxy 
udp  0  0 0.0.0.0:56562   0.0.0.0:*       1042/haproxy 
root@10.1.6.203:~# netstat -tunlp | grep xine
tcp  0  0 10.1.6.203:9222  0.0.0.0:*    LISTEN  30897/xinetd 
root@10.1.6.203:~# ps -ef | grep haproxy
root  1042  1 0 Sep17 ?  00:00:00 /usr/local/sbin/haproxy -f /etc/haproxy/haproxy.cfg

测试:

通过vip10.1.6.173 3366访问cluster数据库(注意账户dave权限需要加3个ip10.1.6.203,10.1.6.205,10.1.6.173)

root@10.1.6.203:mgm# mysql -udave -p -h 10.1.6.173 -P 3366
Enter password: 
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1344316
Server version: 5.5.22-ndb-7.2.6-gpl-log MySQL Cluster Community Server (GPL)
 
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
 
mysql> show databases;
+--------------------+
| Database   |
+--------------------+
| information_schema | 
| dave    | 
| test    | 
+--------------------+
3 rows in set (0.01 sec)
 
mysql>

手动分别使keepalive,haproxy,数据库挂掉.vip10.1.6.173会自动漂到10.1.6.205从上,并不影响vip的访问

通过vip,haproxy查看各节点状态

http://10.1.6.173:8888/status

通过Keepalived+HAProxy实现MySQL高可用负载均衡配置的教程介绍


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Tags: 实现 mysql Keepalived+HAProxy
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