Nginx+Keepalived实现

一、Keepalived简介
keepalived是一个类似于layer3, 4 & 5交换机制的软件，也就是我们平时说的第3层、第4层和第5层交换。Keepalived的作用是检测web服务器的状态，如果有一台web服务器死机，或工作出现故障，Keepalived将检测到，并将有故障的web服务器从系统中剔除，当web服务器工作正常后Keepalived自动将web服务器加入到服务器群中，这些工作全部自动完成，不需要人工干涉，需要人工做的只是修复故障的web服务器。
-----百科资料
二、规划

1234	OS:CentOS7Nginx_Master: 192.168.10.128 Nginx主机Nginx_BackUp: 192.168.10.145 Nginx备机Nginx_VIP1: 192.168.10.111 虚拟IP地址

说明:
虚拟IP是外网访问的IP地址，通过keepalived设置，以及VRRP将虚拟IP地址绑定到主机和备机上,通过权重实现控制。当主机挂掉后，keepalived 释放对主机的控制，备机接管虚拟IP地址。

三、下载相关软件包

123	# yum install -y gcc openssl openssl-devel# wget http://www.keepalived.org/software/keepalived-1.2.19.tar.gz ##下载Keeplived# wget http://nginx.org/download/nginx-1.9.4.tar.gz

四、编译Nginx
①编译

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# groupadd -r nginx# useradd -r -g nginx nginx# tar -zxvf nginx-1.9.4.tar.gz# cd nginx-1.9.4/# ./configure \ --prefix=/usr \ --sbin-path=/usr/sbin/nginx \ --conf-path=/etc/nginx/nginx.conf \ --error-log-path=/var/log/nginx/error.log \ --http-log-path=/var/log/nginx/access.log \ --pid-path=/var/run/nginx/nginx.pid \ --lock-path=/var/lock/nginx.lock \ --user=nginx \ --group=nginx \ --with-http_ssl_module \ --with-http_flv_module \ --with-http_stub_status_module \ --with-http_gzip_static_module \ --http-client-body-temp-path=/var/tmp/nginx/client/ \ --http-proxy-temp-path=/var/tmp/nginx/proxy/ \ --http-fastcgi-temp-path=/var/tmp/nginx/fcgi/ \ --http-uwsgi-temp-path=/var/tmp/nginx/uwsgi \ --http-scgi-temp-path=/var/tmp/nginx/scgi \ --with-pcre# make# make install# /usr/sbin/nginx ##开启nginx

②简单配置nginx

1234	# vi /etc/nginx/nginx.conf server { listen 80; server_name www.zhi.com;

Master:

123	# vi /usr/html/index.html<h1>Success!</h1><p>Welcome to LINUX Keepalived System 1!</p>

BackUp:

123	# vi /usr/html/index.html<h1>Success!</h1><p>Welcome to LINUX Keepalived System 2!</p>

五、编译Keeplived

123	# tar -zxvf keepalived-1.2.19.tar.gz # cd keepalived-1.2.19# ./configure --sysconf=/etc --prefix=/usr/local/keepalived

12	# make# make install

六、配置Keeplived

①设置开机自启动并配置服务脚本

123	# cp /usr/local/keepalived/sbin/keepalived /usr/sbin/# /etc/init.d/keepalived start# systemctl start keepalived ##以上皆可启动keepalived

12	# chkconfig --add keepalived# chkconfig keepalived on

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# vi /etc/keepalived/check_nginx.sh ##配置nginx服务监控脚本!/bin/bashif [ $(ps -C nginx --no-header |wc -l) -eq 0 ]then /usr/sbin/nginxfisleep 2if [ $(ps -C nginx --no-header |wc -l) -eq 0 ]then /etc/init.d/keepalived stopfi# chmod u+x /etc/keepalived/check_nginx.sh

注:该脚本检测nginx服务正常开启与否，使自动切换keepalived虚拟IP地址。如无该脚本，必须手动执行关闭keepalived方可切换。

②MASTER配置

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# vi /etc/keepalived/keepalived.conf! Configuration File for keepalivedglobal_defs { notification_email { root@localhost ##设置报警邮件地址,可以设置多个} notification_email_from zhi@zhi.com ##设置邮件发送地址 smtp_server 127.0.0.1 ##设置SMTP-Server地址 smtp_connect_timeout 30 ##设置连接超时时间 router_id LVS_DEVEL ##运行keepalived服务的标识,显示在邮件主题的信息} vrrp_script check_nginx {script "/etc/keepalived/check_nginx.sh" ##Nginx服务监控脚本interval 2 ##脚本执行间隔weight 2 ##脚本执行结果导致的优先级变更} vrrp_instance VI_1 { state MASTER ##指定keepalived角色为主服务器 interface eno16777736 ##指定HA监测网络的接口 virtual_router_id 51 ##虚拟路由标识，同一个vrrp实例使用唯一的标识 priority 101 ##定义优先级，数字越大，优先级越高 advert_int 1 ##设定MASTER与BACKUP负载均衡器间同步检查的时间间隔,单位秒 authentication { ##设置验证类型和密码 auth_type PASS ##设置验证类型，主要有PASS和AH两种 auth_pass 1111 ##设置验证密码,同一vrrp_instance密码必须相同 } track_script { check_nginx ##检测执行脚本} virtual_ipaddress { 192.168.10.111/24 #设置虚拟IP地址,可设置多个虚拟IP地址 }} virtual_server 192.168.10.111 80 { ##设置虚拟服务器，指定虚拟IP地址和服务端口 delay_loop 6 ##设置运行情况检查时间，单位秒 lb_algo rr ##设置负载调度算法,rr即轮询算法 lb_kind NAT ##设置LVS实现负载均衡的机制，有NAT、TUN、DR三个模式可选 nat_mask 255.255.255.0 persistence_timeout 50 ##会话保持时间，单位秒 protocol TCP ##指定转发协议类型，有TCP和UDP两种 sorry_server 127.0.0.1 80 real_server 192.168.10.128 80 { ##配置服务节点1，指定real server的真实IP和端口 weight 1 ##配置服务节点的权值，数字越大，权值越高 HTTP_GET { url { path / status_code 200 ##200状态码，表示服务器已成功处理请求 } connect_timeout 3 ##响应超时时间 nb_get_retry 3 ##重试次数 delay_before_retry 3 ##重试间隔 } } real_server 192.168.10.145 80 { weight 1 HTTP_GET { url { path / status_code 200 } connect_timeout 3 nb_get_retry 3 delay_before_retry 3 } }}

③BACKUP配置

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# vi /etc/keepalived/keepalived.conf! Configuration File for keepalivedglobal_defs { notification_email { root@localhost } notification_email_from zhi@zhi.com smtp_server 127.0.0.1 smtp_connect_timeout 30 router_id LVS_DEVEL} vrrp_script check_nginx { script "/etc/keepalived/check_nginx.sh" ##Nginx服务监控脚本 interval 2 weight 2} vrrp_instance VI_1 { state BACKUP interface eno16777736 virtual_router_id 51 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 1111 } track_script { check_nginx ##检测脚本} virtual_ipaddress { 192.168.10.111/24 }}virtual_server 192.168.10.111 80 { delay_loop 6 lb_algo rr lb_kind NAT nat_mask 255.255.255.0 persistence_timeout 50 protocol TCP sorry_server 127.0.0.1 80 real_server 192.168.10.128 80 { weight 1 HTTP_GET { url { path / status_code 200 } connect_timeout 3 nb_get_retry 3 delay_before_retry 3 } } real_server 192.168.10.145 80 { weight 1 HTTP_GET { url { path / status_code 200 } connect_timeout 3 nb_get_retry 3 delay_before_retry 3 } }}

④查看系统日志

1	# tail /var/log/messages

注:这是192.168.10.145的日志(没有同步时间),由于更改配置后没有重启Master,所以BACKUP进行了抢占

Master:

12	# systemctl restart keepalived.service# tail /var/log/messages

1

# ip addr

七、测试

浏览器输入www.zhi.com测试




Master:

1	# nginx -s stop

BackUp:

1

# ip addr

虚拟IP地址已切换至备机了

刷新www.zhi.com，可能反应较慢




另:可配置nginx+keepalived主主模式，并在后端配置反向代理和负载均衡实现高可用

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