ngin+keepalived实现高可用负载均衡方案

学习文档目录TOC\o"1-5"\h\z\o"CurrentDocument"1. 引言 32. 环境说明 3\o"CurrentDocument"3. Nginx安装配置 3\o"CurrentDocument"4. Keepalived安装配置 5\o"CurrentDocument"5. 验证 91.引言本学习文档主要介绍了采用Nginx负载均衡，通过keepalived实现Nginx双机互备，保证实现的WEB服务高可用方案。2.环境说明主nginx负载均衡器：0端口81（CentOSrelease5.8）副nginx负载均衡器：1端口81（CentOSrelease5.8）Tomcat1:9端口3030Tomcat2:0端口4040VIP:2软件：keepalived-1.2.12nginx-1.4.4说明：keepalived是一个基于VRRP协议来实现的WEB服务高可用方案，可以利用其来避免单点故障。一个WEB服务至少会有2台服务器运行Keepalived,一台为主服务器（MASTER）,一台为备份服务器（BACKUP）,但是对外表现为一个虚拟IP,主服务器会发送特定的消息给备份服务器，当备份服务器收不到这个消息的时候，即主服务器宕机的时候，备份服务器就会接管虚拟IP,继续提供服务，从而保证了高可用性。3.Nginx安装配置1.安装Nginx获取Nginx稳定版,把Nginx安装到/usr/local/nginx目录下（两台机器都安装）的详细步骤:yum-installgccopenssl-develpcre-develzlib-devel（安装相关组件）tarzxvfnginx-1.4.4.tar.gzcdnginx-1.4.4./configure--prefix=/usr/local/nginx--with-http_ssl_module

--with-http_flv_module--with-http_gzip_static_module--with-http_stub_status_modulemake&&makeinstall2.分别在两台服务器编写配置文件vim/usr/local/nginx/conf/nginx.conf#usernobody;worker_processes1;#pidlogs/nginx.pid;events{worker_connections1024;http{includedefault_typesendfilemime.types;includedefault_typesendfileon;application/octet-stream;on;#tcp_nopushon;keepalive_timeout65;upstreamcart{server9:3030weight=1;server0:4040weight=1;#ip_hash; #在没有做共享session的情况下ip_hash可以解决session问题}server{listen81;server_name0;#另外一台填写另外IPcharsetutf-8;location/cart{roothtml;indexindex.htmlindex.htm;proxy_next_upstreamerrortimeouthttp_500http_502http_504;proxy_read_timeout10s;proxy_passhttp://cart;

proxy_set_headerHost$host:81;#没用默认proxy_set_headerHost$host:81;#没用默认80端口需要加入$remote_addr;proxy_set_headerX-Forwarded-For$proxy_add_x_forwarded_for;proxy_set_headererror_page500502503504/50x.html;location=/50x.html{roothtml;}log_formataccess_log'$remote_addr-$remote_user[$time_local]$request'"$status"$body_bytes_sent"$http_referer"''"$http_user_agent""$http_x_forwarded_for"';access_log/usr/local/nginx/logs/access.logaccess_log;}}3.验证配置文件正确性/usr/local/nginx/sbin/nginx-显示以下信息为正确的theconfigurationfile/usr/local/nginx/conf/nginx.confsyntaxisokconfigurationfile/usr/local/nginx/conf/nginx.conftestissuccessful4.启动/usr/local/nginx/sbin/nginx4.Keepalived安装配置1.安装（两台nginx机器都安装）#安装poptyum-yinstallpoptpopt-develtarzxvfkeepalived-1.2.12.tar.gzcdkeepalived-1.2.12./configure--prefix=/usr/local/keepalived--sysconf=/etcmake&&makeinstallcp/usr/local/keepalived/sbin/keepalived/bin/chkconfig--addkeepalived#设置开机启动chkconfigkeepalivedon#启动keepalive服务/etc/init.d/keepalivedstartservicekeepalivedrestart2.配置cp/etc/keepalived/keepalived.conf/etc/keepalived/keepalived.conf_bakMASTERvim/etc/keepalived/keepalived.conf!ConfigurationFileforkeepalivedglobal_defs{notification_email{jiyulong@gufanbiao@}notification_email_fromjiyulong@smtp_serversmtp_connect_timeout30router_idLVS_DEVEL}vrrp_scriptMonitor_Nginx{script"/root/monitor/monitor_nginx.sh"interval2weight2}vrrp_instanceVI_1{stateMASTER#（主机为MASTER，备用机为BACKUP）interfaceethO#（HA监测网络接口）virtual_router_id51#（主、备机的virtual_router_id必须相同）priority1OO#（主、备机取不同的优先级，主机值较大，备份机值较小,值越大优先级越高）advert_int1#（VRRPMulticast广播周期秒数）authentication{auth_typePASS#（VRRP认证方式）auth_pass1111#（密码）}track_script{Monitor_Nginx#（调用nginx进程检测脚本）}virtual_ipaddress{2#（VRRPHA虚拟地址）}}BACKUP方面只需要修改state为BACKUP,priority比MASTER稍低即可3.监控脚本vim/root/monitor_nginx.sh当检测到nginx进程不存在的时候，就干掉所有的keepalived，这时候，请求将会由keepalived的backup接管！！vim/opt/nginx_pid.sh#!/bin/bashvarsion0.0.2根据一网友说这样做不科学，如果nginx服务起来了，但是我把keepalived杀掉了，我的理由是，如果nginx死掉了，我觉得就很难在起来，再有就是nagios当然要给你报警了啊。不过这位同学说的有道理，所以就稍加改了一下脚本##查看是否有nginx进程把值赋给变量AA='ps-Cnginx--no-header|wc-I'if[$A-eq0];then ##如果没有进程值得为零/usr/local/nginx/sbin/nginxsleep3if['ps-Cnginx--no-header|wc-l'-eq0];thenkillallkeepalived ##则结束keepalived进程fifi运行chmod+x/root/monitor_nginx.sh赋权限注意:运行monitor_nginx.sh脚本时出现了这错误/bin/bash人M:badinterpreter:没有那个文件或目录。原因：linux和windows之间的不完全兼容。。。具体细节不管，如果验证:vimXXX.sh:setff?如果出现fileforma=dos那么就基本可以确定是这个问题了。:setfileformat=unix:wqOK了。。。。。。。4.启动01都重新启动keepalived：servicekeepalivedrestart这里请注意，当keepalived启动后，我们可以用命令：ipaddshowethO来看我们的ethO网卡确实被添加了虚拟IP,如图[root@terracotta2keepalived]#ipaddshowethO2：etho：<BROADCA^TfMULTICAST,UP,LOWER_UP>mtu1500qdiscpfifofastqlen1000link/ether00:50:56:8b:5b:02brdff:ff:ff:ff:ff:ffFnet0/24Jard55scopeglobalethOlinet2/32scopeglobalethOinet丄2/24brd丄55scopeglobalsecondaryethO:0inet6fe80::250:56ff:fe8b:5b02/64scopelinkvalidlftforeverpzeferredlftforever注：给大家提供加虚IP的方法egifconfigethO:OOOnetmask255.255.255.OupipaddshowethO来看我们的ethO网卡确实被添加了虚拟IP5.验证1访问VIP看是否能够正常访问后端的tomcat2•停止其中一个tomcat看是否能将访问转到另一台上停止两台nginx上任何一个nginx进程看监控进程脚本是否会自动启动nginx停止任何一台nginx上的keepalived进程看另一台是否接管vip比如停止Master上的keepalived,例如如下killallkeepalived,查看BACKUP机器是否已经接管，如果BACKUP接管后，BACKUP机器日志会是出下情况日志路径：tail/var/log/messagesKeepalived_vrrp:VRRP_Instance(VI_1)TransitiontoMASTERSTATEKeepalived_vrrp:VRRP_Instance(VI_1)EnteringMASTERSTATEKeepalived_vrrp:VRRP_Instance(VI_1)settingprotocolVIPs.Keepalived_vrrp:VRRP_Instance(VI_1)SendinggratuitousARPsoneth0for2MASTER/