Nginx高可用集群实战

jhhll1

   一、简介
    上一篇博文介绍了keepalived的高可用集群，其实使用nginx做前端代理，负载均衡照样可以实现双主或主备模式的高可用集群比起keepalived基于lvs的dr配置更为简单易学，下面是本人所理解的nginx高可用集群。此实验拓扑图类似keepalived拓扑，把图中keepalived字样换成nginx即可，我就不画了，有意者可重画。
实验拓扑图：


    二、nginx主备模式高可用

    配置nginx的upstream模块，让其反代到后端主机，后端主机配置和keepalived中雷同即可。

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upstream websrvs {         server 10.1.10.5:80;    #后端主机real server01         server 10.1.10.6:80;     #后端主机real server02         server 10.1.10.2:80 backup; #当后端主机均不能响应时此主机响应应急页面     }

    配置keepalived配置文件，实现VIP地址漂移

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! Configuration File for keepalived global_defs { notification_email { root@localhost } notification_email_from keepalived@localhost smtp_server 127.0.0.1 smtp_connect_timeout 30 router_id node1 vrrp_mcast_group4 224.0.100.18 } vrrp_script chk_down { script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0" interval 1 weight -5 } vrrp_script chk_nginx { script "killall -0 nginx && exit 0 || exit 1" interval 1 weight -5 } vrrp_instance VI_1 { state MASTER interface eno16777736 virtual_router_id 57 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 98181111 } virtual_ipaddress { 10.1.10.7/16 dev eno16777736 } track_script { chk_down chk_httpd } notify_master "/etc/keepalived/notify.sh master" notify_backup "/etc/keepalived/notify.sh backup" notify_fault "/etc/keepalived/notify.sh fault" }

实现图：
模拟单台后端主机无法提供服务及其全部宕机实验结果如下：


    上诉结果可看出，此实验成功的展示了主备模式下的nginx反代，实现高可用。此实验课检测nginx的健康状态及其主备模式的切换时发邮件给管理员。


    三、nginx主主模式高可用
    配置keepalived配置文件，实现VIP地址漂移，和上诉主备相似

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! Configuration File for keepalived global_defs { notification_email { root@localhost } notification_email_from keepalived@localhost smtp_server 127.0.0.1 smtp_connect_timeout 30 router_id node1 vrrp_mcast_group4 224.0.120.18 } vrrp_script chk_down { #检测此文件下是否存在down这个文件，灰度模式下上线时可使用此 script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0" interval 1 weight -5 } vrrp_script chk_nginx { #检测nginx的健康状态信息 script "killall -0 nginx && exit 0 || exit 1" interval 1 weight -5 } vrrp_instance VI_1 { state MASTER interface eno16777736 virtual_router_id 53 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 9818sss1 } virtual_ipaddress { 10.1.10.7/16 dev eno16777736 } track_script { chk_down chk_nginx } notify_master "/etc/keepalived/notify.sh master" notify_backup "/etc/keepalived/notify.sh backup" notify_fault "/etc/keepalived/notify.sh fault" } vrrp_instance VI_2 { state BACKUP interface eno16777736 virtual_router_id 54 priority 98 advert_int 1 authentication { auth_type PASS auth_pass 9818rss1 } virtual_ipaddress { 10.1.10.77/16 dev eno16777736 } track_script { chk_down chk_nginx } notify_master "/etc/keepalived/notify.sh master" notify_backup "/etc/keepalived/notify.sh backup" notify_fault "/etc/keepalived/notify.sh fault" }

此时，nginx上keepalived均启动结果如图：


模拟后端主机宕机及其恢复正常结果类似keepalived如图所示：



到此，nginx的高可用集群均已实现，做实验的方法和keepalived有很多相似之处。