keepalived通过VRRP协议实现高可用功能的。VRRP（Virtual Router Redundancy Protocol）虚拟路由冗余协议。VRRP出现的目的就是为了解决静态路由单点故障问题，它能保证当个别节点宕机时，整个网络可以不间断地运行。
当主节点发生故障时，无法给备节点发送心跳消息，如果备节点无法继续检测到来自主节点的心跳。就会调用自身的接管程序，接管主节点的IP资源和服务。当主节点恢复时，备节点又会释放主节点故障时自身接管的IP资源和服务，恢复到原来的备用角色
3.1.主节点（192.168.80.22）
3.1.1.安装编译工具和库文件
yum -y install make zlib zlib-devel gcc-c++ libtool openssl openssl-devel
3.1.2.安装pcre
#进入目录 cd /usr/local/develop/anginx #上传安装文件并解压 tar -zxvf pcre-8.38.tar.gz #进入安装目录 cd pcre-8.38 #检查配置 ./configure #编译、安装 make && make install #查看pcre版本 pcre-config --version
3.1.3.安装nginx
#进入目录 cd /usr/local/develop/anginx #上传安装文件，并解压 tar -zxvf nginx-1.8.1.tar.gz #进入安装目录 cd nginx-1.8.1 #检查配置 ./configure --prefix=/usr/local/develop/anginx/webserver/nginx --with-http_stub_status_module --with-http_ssl_module --with-pcre=/usr/local/develop/anginx/pcre-8.38 #编译安装 make && make install #查看nginx版本 /usr/local/develop/anginx/webserver/nginx/sbin/nginx -v -------------------------------------------------------- [root@hadoop02 webserver]# /usr/local/develop/anginx/webserver/nginx/sbin/nginx -v nginx version: nginx/1.8.1 #配置nginx（检查） /usr/local/develop/anginx/webserver/nginx/sbin/nginx -t #nginx管理命令 /usr/local/develop/anginx/webserver/nginx/sbin/nginx # 启动 Nginx /usr/local/develop/anginx/webserver/nginx/sbin/nginx -s stop # 停止 Nginx /usr/local/develop/anginx/webserver/nginx/sbin/nginx -s reload # 重新载入配置文件 /usr/local/develop/anginx/webserver/nginx/sbin/nginx -s reopen # 重启 Nginx
3.1.4.nginx基础配置
vi nginx.conf #user nobody; worker_processes 1; #error_log logs/error.log; #error_log logs/error.log notice; #error_log logs/error.log info; pid logs/nginx.pid; events { worker_connections 1024; } http { include mime.types; default_type application/octet-stream; log_format main '$remote_addr - $remote_user [$time_local] "$request" ' '$status $body_bytes_sent "$http_referer" ' '"$http_user_agent" "$http_x_forwarded_for"'; access_log logs/access.log main; sendfile on; #tcp_nopush on; #keepalive_timeout 0; keepalive_timeout 65; #gzip on; #添加tomcat列表，真实应用服务器都放在这 upstream tomcat_pool{ #server tomcat地址:端口号 weight表示权值，权值越大，被分配的几率越大; server 192.168.80.22:8080 weight=4 max_fails=2 fail_timeout=30s; server 192.168.80.22:8081 weight=4 max_fails=2 fail_timeout=30s; } server { listen 80; server_name tomcat_pool; #charset koi8-r; #access_log logs/host.access.log main; location / { #root html; #index index.html index.htm; proxy_pass http://tomcat_pool; #转向tomcat处理 proxy_set_header Host $host; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; } #error_page 404 /404.html; # redirect server error pages to the static page /50x.html # error_page 500 502 503 504 /50x.html; location = /50x.html { root html; } }
3.2.备节点（192.168.80.21）
说明：安装方式同nginx主节点。
4.安装keepalived
4.1.主节点（192.168.80.22）
#安装keepalived yum install keepalived -y #启动keepalived服务 /etc/init.d/keepalived start ------------------------------------------- [root@hadoop02 anginx]# /etc/init.d/keepalived start 正在启动 keepalived： [确定] [root@hadoop02 anginx]# ps -ef |grep keepalived root 15723 1 0 00:59 ? 00:00:00 /usr/sbin/keepalived -D root 15724 15723 0 00:59 ? 00:00:00 /usr/sbin/keepalived -D root 15725 15723 0 00:59 ? 00:00:00 /usr/sbin/keepalived -D root 15731 15622 0 00:59 pts/1 00:00:00 grep keepalived [root@hadoop02 anginx]# #设置开机自启动 echo "/etc/init.d/keepalived start" >>/etc/rc.local #关闭keepalived服务 /etc/init.d/keepalived stop #编辑keepalived配置文件 vi /etc/keepalived/keepalived.conf ----------------------------------------------------------- ! Configuration File for keepalived global_defs { notification_email { acassen@firewall.loc failover@firewall.loc sysadmin@firewall.loc } notification_email_from Alexandre.Cassen@firewall.loc smtp_server 192.168.200.1 smtp_connect_timeout 30 router_id lb01 } vrrp_instance VI_1 { state MASTER interface eth1 virtual_router_id 55 priority 150 advert_int 1 authentication { auth_type PASS auth_pass server123 } virtual_ipaddress { 192.168.80.100 dev eth1 label eth1:1 } } ...........................................................
关于配置说明：
【router_id】 是路由标识，在一个局域网里面应该是唯一的
【vrrp_instance VI_1】{...}这是一个VRRP实例，里面定义了keepalived的主备状态、接口、优先级、认证和IP信息
【state】 定义了VRRP的角色
【interface】定义使用的接口，这里我的服务器用的网卡都是eth1
【virtual_router_id】是虚拟路由ID标识，一组的keepalived配置中主备都是设置一致
【priority】是优先级，数字越大，优先级越大，
【auth_type】是认证方式
【auth_pass】是认证的密码
【virtual_ipaddress】 ｛...｝定义虚拟IP地址，可以配置多个IP地址，这里我定义为192.168.80.100，绑定了eth1的网络接口，虚拟接口eth1:1
4.2.备节点（192.168.80.21）
#安装keepalived yum install keepalived -y #启动keepalived服务 /etc/init.d/keepalived start ------------------------------------------- [root@hadoop02 anginx]# /etc/init.d/keepalived start 正在启动 keepalived： [确定] [root@hadoop02 anginx]# ps -ef |grep keepalived root 15723 1 0 00:59 ? 00:00:00 /usr/sbin/keepalived -D root 15724 15723 0 00:59 ? 00:00:00 /usr/sbin/keepalived -D root 15725 15723 0 00:59 ? 00:00:00 /usr/sbin/keepalived -D root 15731 15622 0 00:59 pts/1 00:00:00 grep keepalived [root@hadoop02 anginx]# #设置开机自启动 echo "/etc/init.d/keepalived start" >>/etc/rc.local #关闭keepalived服务 /etc/init.d/keepalived stop #编辑keepalived配置文件 vi /etc/keepalived/keepalived.conf ----------------------------------------------------------------- ! Configuration File for keepalived global_defs { notification_email { acassen@firewall.loc failover@firewall.loc sysadmin@firewall.loc } notification_email_from Alexandre.Cassen@firewall.loc smtp_server 192.168.200.1 smtp_connect_timeout 30 router_id lb02 } vrrp_instance VI_1 { state BACKUP interface eth1 virtual_router_id 55 priority 100 advert_int 1 authentication { auth_type PASS auth_pass server123 } virtual_ipaddress { 192.168.80.100 dev eth1 label eth1:1 } } .............................................................
5.测试
5.1.启动主备节点的keepalived服务
#在节点一执行（192.168.80.22） /etc/init.d/keepalived start ------------------------------------- [root@hadoop02 anginx]# ps -ef |grep keepalived root 15788 1 0 01:09 ? 00:00:00 /usr/sbin/keepalived -D root 15790 15788 0 01:09 ? 00:00:00 /usr/sbin/keepalived -D root 15791 15788 0 01:09 ? 00:00:00 /usr/sbin/keepalived -D root 15807 15622 0 01:33 pts/1 00:00:00 grep keepalived [root@hadoop02 anginx]# #在节点二执行（192.168.80.21） /etc/init.d/keepalived start --------------------------------------- [root@hadoop01 ~]# ps -ef |grep keepalived root 11542 1 0 01:30 ? 00:00:00 /usr/sbin/keepalived -D root 11544 11542 0 01:30 ? 00:00:00 /usr/sbin/keepalived -D root 11545 11542 0 01:30 ? 00:00:00 /usr/sbin/keepalived -D root 11550 11512 0 01:33 pts/1 00:00:00 grep keepalived [root@hadoop01 ~]#
5.2.通过虚ip访问服务
http://192.168.80.100/session-redis-demo/
5.3.停止主节点keepalived服务
#在节点一执行（192.168.80.22） /etc/init.d/keepalived stop #观察备节点变化 ip addr ------------------------------------------- [root@hadoop01 ~]# ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 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 inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:50:56:38:e5:46 brd ff:ff:ff:ff:ff:ff inet 192.168.80.21/24 brd 192.168.80.255 scope global eth1 inet 192.168.80.100/32 scope global eth1:1 inet6 fe80::250:56ff:fe38:e546/64 scope link valid_lft forever preferred_lft forever [root@hadoop01 ~]#
5.4.继续通过虚ip访问服务
http://192.168.80.100/session-redis-demo/
6.keepalived+nginx整合
说明：编写nginx守护脚本，如果nginx服务出现故障，则停止当前节点的keepalived服务。自动切换到备用节点。
6.1.编写nginx守护脚本
vi nginx_check.sh -------------------------------------- #!/bin/bash while true do if [ $(netstat -tlnp|grep nginx|wc -l) -ne 1 ] then /etc/init.d/keepalived stop fi sleep 2 done #给脚本授权 chmod u+x nginx_check.sh #执行脚本 nohup /usr/local/develop/anginx/shell/nginx_check.sh &
6.2.停止主节点nginx服务
#停止主节点nginx服务 /usr/local/develop/anginx/webserver/nginx/sbin/nginx -s stop #查找进程 [root@hadoop02 ~]# ps -ef |grep nginx root 15915 1 0 01:51 ? 00:00:00 /bin/bash /usr/local/develop/anginx/shell/nginx_check.sh root 16516 15753 0 01:54 pts/5 00:00:00 grep nginx [root@hadoop02 ~]# #观察备用节点变化【服务正常】 ip addr -------------------------------------- [root@hadoop01 shell]# ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 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 inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:50:56:38:e5:46 brd ff:ff:ff:ff:ff:ff inet 192.168.80.21/24 brd 192.168.80.255 scope global eth1 inet 192.168.80.100/32 scope global eth1:1 inet6 fe80::250:56ff:fe38:e546/64 scope link valid_lft forever preferred_lft forever [root@hadoop01 shell]# #再次重新启动主节点nginx和keepalived服务 /usr/local/develop/anginx/webserver/nginx/sbin/nginx /etc/init.d/keepalived start