基于Keepalived的Nginx高可用实践

# yum -y install httpd
# systemctl enable httpd
# echo "node 1" > /var/www/html/index.html
# systemctl start httpd

# yum -y install nginx #在Node2上执行类似操作
# systemctl enable nginx
# echo "Nginx A" > /usr/share/nginx/html/index.html 
# vim /etc/nginx/nginx.conf
 19       upstream webser{
 20         server 192.168.26.136 weight=1;
 21         server 192.168.26.132 weight=2;
 22     }
 23         
 24     server {
 25         listen 80 default_server;
 26         server_name _;
 27         root /usr/share/nginx/html;
 28         location / {
 29             proxy_pass webser;
 30         }
 31     }

# nginx -t
# systemctl start nginx

# yum -y install keepalived.x86_64 
# systemctl enable keepalived.service
# cd /etc/keepalived/
# cp keepalived.conf{,.bak}
# vim keepalived.conf
! Configuration File for keepalived #类似于Bash Shell的shebang机制
global_defs {
   notification_email { #收件人列表，可有多个
     root@localhost
   }
   notification_email_from keepalived@localhost #发件人地址
   smtp_server localhost #smtp服务器
   smtp_connect_timeout 30 #超时时长
   router_id ha_cluster_1_1 #主机身份唯一标识符，同一高可用集群中必须唯一
   vrrp_skip_check_adv_addr
   vrrp_mcast_group4 224.18.0.100 #VRRP多播地址
   vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}
 
vrrp_instance VI_1 { #虚拟路由器名称，同一高可用集群中必须唯一
    state MASTER # 当前节点在此虚拟路由器上的身份，可选值为 {MASTER:SLAVE}
    interface ens34 #该虚拟路由器在本机上所使用的物理网卡
    virtual_router_id 51 #当前虚拟路由器惟一标识，范围是0-255, 同一虚拟路由器中，该值必须相同
    priority 100 #当前物理节点在此虚拟路由器中的优先级；范围1-254
    advert_int 1 #VRRP通告间隔
    authentication {
        auth_type PASS      #通过密钥认证
        auth_pass b1acd829  #预共享密钥 可由"openssl rand -hex N"生成，仅前八位有效
    }
    virtual_ipaddress { #对外提供服务的VIP
        172.18.59.100/16 dev ens34 label ens34:0
    }
    track_interface { #对网卡设备做冗余 以备流式迁移
        ens33 weight 1
        ens34 weight 2 
    }
}
# systemctl start keepalived.service

# vim keepalived.conf

# systemctl restart keepalived.service

# systemctl stop keepalived

# vim /etc/keepalived/keepalived.conf #以下脚本意为：当Nginx服务意外停止运行时，将每隔1s进行检测，一旦失败2次则将本机Keepalived服务的优先级降低20，反之判定失败后，如果后续检测中有1次成功，则视为成功。

# systemctl stop nginx

# systemctl start nginx