企业级高可用Web架构之HAPorxy+Keepalived.docx

企业级高可用Web架构之HAPorxy+Keepalived细数下来，算是东莞的项目的话，HAProxy+Keepalived我差不多也有三套在线上跑了，另外，这套Web方案也是我的一拍网的备份方案之一，目前也在测试，如果速度和稳定性够强劲的话，我也考虑将LVS+Keepalived换成HAProxy+Keepalived，关于HAProxy的语法和安装步骤请参考我的专题系列文章/art/201101/241997.htm，另外，此篇文章跟天斯兄的不一样，我主要用其作为Web级别的负载均衡（七层应用）。一、线上跑的HAProxy配置文件，代码如下：1. global2. loglocal03. maxconn655354. chroot/usr/local/haproxy5. uid996. gid997. daemon8. nbproc89. pidfile/usr/local/haproxy/haproxy.pid10. debug11. 12. defaults13. loglocal314. modehttp15. optionhttplog16. optionhttpclose17. optiondontlognull18. optionforwardfor19. optionredispatch20. retries221. maxconn200022. balancesource23. statsuri/web-status24. contimeout500025. clitimeout5000026. srvtimeout5000027. 28. 29. bind*:8030. modehttp31. optionhttplog32. logglobal33. optionhttpchkHEAD/index.jspHTTP/1.034. serverweb147:80weight5checkinter2000rise2fall335. serverweb246:80weight3checkinter2000rise2fall3二、HAProxy的启动、关闭和重启脚本，代码如下：1. #!/bin/sh2. #chkconfig35on3. #description:HAProxyisaTCP/HTTPreverseproxywhichisparticularlysuitedforhighavailabilityenvironments.4. 5. #Sourcefunctionlibrary.6. if-f/etc/init.d/functions;then7. ./etc/init.d/functions8. elif-f/etc/rc.d/init.d/functions;then9. ./etc/rc.d/init.d/functions10. else11. exit012. fi13. 14. #Sourcenetworkingconfiguration.15. ./etc/sysconfig/network16. 17. #Checkthatnetworkingisup.18. $NETWORKING=no&exit019. 20. -f/usr/local/haproxy/conf/haproxy.cfg|exit121. 22. RETVAL=023. 24. start()25. /usr/local/haproxy/sbin/haproxy-c-q-f/usr/local/haproxy/conf/haproxy.cfg26. if$?-ne0;then27. echoErrorsfoundinconfigurationfile.28. return129. fi30. 31. echo-nStartingHAproxy:32. daemon/usr/local/haproxy/sbin/haproxy-D-f/usr/local/haproxy/conf/haproxy.cfg-p/var/run/haproxy.pid33. RETVAL=$?34. echo35. $RETVAL-eq0&touch/var/lock/subsys/haproxy36. return$RETVAL37. 38. 39. stop()40. echo-nShuttingdownHAproxy:41. killprochaproxy-USR142. RETVAL=$?43. echo44. $RETVAL-eq0&rm-f/var/lock/subsys/haproxy45. $RETVAL-eq0&rm-f/var/run/haproxy.pid46. return$RETVAL47. 48. 49. restart()50. /usr/local/haproxy/sbin/haproxy-c-q-f/usr/local/haproxy/conf/haproxy.cfg51. if$?-ne0;then52. echoErrorsfoundinconfigurationfile,checkitwithhaproxycheck.53. return154. fi55. stop56. start57. 58. 59. check()60. /usr/local/haproxy/sbin/haproxy-c-q-V-f/usr/local/haproxy/conf/haproxy.cfg61. 62. 63. rhstatus()64. statushaproxy65. 66. 67. condrestart()68. -e/var/lock/subsys/haproxy&restart|:69. 70. 71. #Seehowwewerecalled.72. case$1in73. start)74. start75. ;76. stop)77. stop78. ;79. restart)80. restart81. ;82. reload)83. restart84. ;85. condrestart)86. condrestart87. ;88. status)89. rhstatus90. ;91. check)92. check93. ;94. *)95. echo$Usage:haproxystart|stop|restart|reload|condrestart|status|check96. RETVAL=197. esac98. 99. exit$RETVAL三、HAProxy的监控脚本我没有做，这个实施起来也简单，我们可以用curl -s -head /index.jsp | awk /HTTP/ print $2的方法，判断是否返回了正常的200代码。 四、大家需要注意的几个地方是：1)HAProyx采用的是balance source机制，它跟Nginx的ip_hash机制原理类似，是让客户机访问时始终访问后端的某一台真实的web服务器，这样让session就固定下来了；2)option httpchk HEAD /index.jsp HTTP/1.0 是网页监控，