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Keepalived+HAProxy實現MySQL高可用負載均衡的配置

編輯：關於MYSQL數據庫

Keepalived

由於在生產環境使用了mysqlcluster,需要實現高可用負載均衡,這裡提供了keepalived+haproxy來實現.

keepalived主要功能是實現真實機器的故障隔離及負載均衡器間的失敗切換.可在第3,4,5層交換.它通過VRRPv2(Virtual Router Redundancy Protocol) stack實現的.

Layer3:Keepalived會定期向服務器群中的服務器.發送一個ICMP的數據包（既我們平時用的Ping程序）,如果發現某台服務的IP地址沒有激活，Keepalived便報告這台服務器失效，並將它從服務器群中剔除，這種情況的典型例子是某台服務器被非法關機。Layer3的方式是以服務器的IP地址是否有效作為服務器工作正常與否的標准。

Layer4:主要以TCP端口的狀態來決定服務器工作正常與否。如web server的服務端口一般是80，如果Keepalived檢測到80端口沒有啟動，則Keepalived將把這台服務器從服務器群中剔除。

Layer5:在網絡上占用的帶寬也要大一些。Keepalived將根據用戶的設定檢查服務器程序的運行是否正常，如果與用戶的設定不相符，則Keepalived將把服務器從服務器群中剔除。

Software Design

2016228164756604.jpg (597×381)

keepalived啟動後會有單個進程

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

父進程:內存管理,子進程管理等等

子進程:VRRP子進程

子進程:Healthchecking 子進程
實例

2台mysqlcluster 10.1.6.203 master 10.1.6.205 backup

vip 10.1.6.173

目的訪問10.1.6.173 3366端口分別輪詢通過haproxy轉發到10.1.6.203 3306 和10.1.6.205 3306

mysqlcluster搭建參照之前博客,這裡在2台機上安裝keepalived

[email protected]:~# apt-get install keepalived
[email protected]:~# 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 {    #注意大括號空格
        chk_haproxy
    }
 
    notify_master /etc/keepalived/scripts/start_haproxy.sh #表示當切換到master狀態時,要執行的腳本
    notify_fault /etc/keepalived/scripts/stop_keepalived.sh #故障時執行的腳本
    notify_stop  /etc/keepalived/scripts/stop_haproxy.sh #keepalived停止運行前運行notify_stop指定的腳本 }

VRRPD配置包括三個類:

VRRP同步組(synchroization group)
VRRP實例(VRRP Instance)
VRRP腳本

這裡使用了 VRRP實例, VRRP腳本

注意配置選項:

stat:指定instance(Initial)的初始狀態，就是說在配置好後，這台服務器的初始狀態就是這裡指定的，但這裡指定的不算，還是得要通過競選通過優先級來確定，裡如果這裡設置為master，但如若他的優先級不及另外一台，那麼這台在發送通告時，會發送自己的優先級，另外一台發現優先級不如自己的高，那麼他會就回搶占為master

interface：實例綁定的網卡，因為在配置虛擬IP的時候必須是在已有的網卡上添加的
priority 101：設置本節點的優先級，優先級高的為master
debug：debug級別
nopreempt:設置為不搶占

vrrp_script chk_haproxy {
    script "killall -0 haproxy"  # verify the pid existance
    interval 2          # check every 2 seconds 腳本執行間隔
    weight -2          # add 2 points of prio if OK 腳本結果導致的優先級變更：2表示優先級+2；-2則表示優先級-2
}

然後在實例(vrrp_instance)裡面引用，有點類似腳本裡面的函數引用一樣：先定義，後引用函數名

    track_script {
        chk_haproxy
    }

注意：VRRP腳本(vrrp_script)和VRRP實例(vrrp_instance)屬於同一個級別

[email protected]: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
[email protected]: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
 
[email protected]: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

[email protected]:~# 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

下面再介紹下haproxy

HAProxy是一款基於TCP(第四層)和HTTP(第七層)應用的代理軟件,它也可作為負載均衡器.可以支持數以萬計的並發連接.同時可以保護服務器不暴露到網絡上,通過端口映射.它還自帶監控服務器狀態的頁面.

安裝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需要對每一個mysqlcluster服務器進行健康檢查

1.在2台主機分別配置haproxy.cfg

[email protected]:scripts# cat /etc/haproxy/haproxy.cfg 
global
    maxconn 51200 #默認最大連接數 
    #uid 99
    #gid 99
    daemon    #以後台形式運行haproxy
    #quiet
    nbproc 1   #進程數量(可以設置多個進程提高性能) 
    pidfile /etc/haproxy/haproxy.pid #haproxy的pid存放路徑,啟動進程的用戶必須有權限訪問此文件 
 
defaults
    mode tcp      #所處理的類別 (#7層 http;4層tcp ) 
    option redispatch  #serverId對應的服務器掛掉後,強制定向到其他健康的服務器 
    option abortonclose #當服務器負載很高的時候，自動結束掉當前隊列處理比較久的連接 
    timeout connect 5000s  #連接超時
    timeout client 50000s #客戶端超時
    timeout server 50000s  #服務器超時
    log 127.0.0.1 local0  #錯誤日志記錄
    balance roundrobin  #默認的負載均衡的方式,輪詢方式 
 
listen proxy
    bind 10.1.6.173:3366  #監聽端口 
    mode tcp        #http的7層模式
    option httpchk    #心跳檢測的文件
    server db1 10.1.6.203:3306 weight 1 check port 9222 inter 12000 rise 3 fall 3   #服務器定義,check inter 12000是檢測心跳頻率 rise 3是3次正確認為服務器可用， fall 3是3次失敗認為服務器不可用，weight代表權重 
    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 #網站健康檢測URL，用來檢測HAProxy管理的網站是否可以用，正常返回200，不正常返回503 
    stats realm Haproxy Manager
    stats auth admin:p@a1SZs24 #賬號密碼

[email protected]:~$ 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.安裝xinetd

[email protected]:~# apt-get install xinetd

3.在每個節點添加xinetd服務腳本和mysqlchk端口號

[email protected]:~# vim /etc/xinetd.d/mysqlchk 
# default: on
# description: mysqlchk
service mysqlchk         #需要在servive定義
{
    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
}
 
[email protected]:~# vim /etc/services 
mysqlchk    9222/tcp            # mysqlchk

4.編寫mysqlchk監控服務腳本

[email protected]:~# ls -l /opt/mysqlchk 
-rwxr--r-- 1 nobody root 1994 2013-09-17 11:27 /opt/mysqlchk
[email protected]:~# 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"   #該賬戶密碼需要在mysql裡添加
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;

測試

2個節點開啟keepalived(主節點會獲得vip,自動拉起haproxy),xinetd

[email protected]:~# 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
[email protected]:~# 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  
[email protected]:~# netstat -tunlp | grep xine
tcp    0   0 10.1.6.203:9222   0.0.0.0:*        LISTEN   30897/xinetd  
[email protected]:~# ps -ef | grep haproxy
root   1042   1 0 Sep17 ?    00:00:00 /usr/local/sbin/haproxy -f /etc/haproxy/haproxy.cfg

測試:

通過vip10.1.6.173 3366訪問cluster數據庫(注意賬戶dave權限需要加3個ip10.1.6.203,10.1.6.205,10.1.6.173)

[email protected]: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>

手動分別使keepalive,haproxy,數據庫掛掉.vip10.1.6.173會自動漂到10.1.6.205從上，並不影響vip的訪問

通過vip,haproxy查看各節點狀態

http://10.1.6.173:8888/status

2016228164844383.jpg (1158×481)