Nginx 高可用 通常 借助 Keepalived 實現， Keepalived 能通過 VRRP （虛擬路由冗余協議）讓多個 Nginx 服務器 組成一個 熱備集群，當主服務器故障時自動切換到備用服務器，保障服務不間斷。

一、環境準備

角色	IP 地址
主服務器（Master）	192.168.159.129
備用服務器（Backup）	192.168.159.130
虛擬IP（VIP）	192.168.159.120
Keepalived版本	1.4.5

二、源碼安裝 Keepalived 服務

2.1 在節點 Mater 上安裝 keepalived

# 安裝依賴
yum install openssl-devel libnl3-devel ipset-devel -y
yum install libnfnetlink-devel -y# 下載源碼
wget https://www.keepalived.org/software/keepalived-1.4.5.tar.gz# 解壓
tar -zxvf  keepalived-1.4.5.tar.gzcd keepalived-1.4.5./configure --prefix=/usr/local/keepalivedmake && make install

2.1.1 配置文件配置

# 配置文件 keepalived.conf 配置
mkdir -p /etc/keepalivedvim keepalived.conf# 配置文件內容
! Configuration File for keepalivedglobal_defs {router_id NGINX_MASTERscript_user rootenable_script_security
}vrrp_instance VI_1 {state MASTERinterface ens33virtual_router_id 51priority 100advert_int 1mcast_src_ip 192.168.159.129authentication {auth_type PASSauth_pass 1111}virtual_ipaddress {192.168.159.200}
}

2.1.2 把keepalived 配置成系統命令

• 創建 服務文件

  vim /etc/systemd/system/keepalived.service[Unit]
  Description=Keepalived High Availability Service
  After=network.target[Service]
  Type=forking
  PIDFile=/var/run/keepalived.pid
  ExecStart=/usr/local/keepalived/sbin/keepalived --pid=/var/run/keepalived.pid --config=/etc/keepalived/keepalived.conf
  ExecReload=/bin/kill -HUP $MAINPID
  KillMode=process
  Restart=on-failure[Install]
  WantedBy=multi-user.target
  

• 重新加載 Systemd 配置并啟動服務

  sudo systemctl daemon-reload
  sudo systemctl start keepalived
  sudo systemctl enable keepalived
  

• 檢查服務狀態

  sudo systemctl status keepalived
  

2.2 在節點 Backup 上安裝 Keepalived

安裝方法與 Master 一致， 配置文件 keepalived.conf 需要修給為以下

! Configuration File for keepalivedglobal_defs {router_id NGINX_BACKUPscript_user rootenable_script_security
}vrrp_instance VI_1 {state BACKUPinterface ens33virtual_router_id 51priority 90advert_int 1mcast_src_ip 192.168.159.130authentication {auth_type PASSauth_pass 1111}virtual_ipaddress {192.168.159.200}
}

三、啟動 keepalived 服務驗證 VIP 是否掛起

四、安裝 Nginx 服務器

pass

五、測試 Nginx

在 Master 上的 Nginx 的 HTML配置 MASTER

在 Backup 上的 Nginx 的 HTML 配置 Buckup

5.1 訪問虛擬 IP 192.168.159.200

5.2 把 Master 的 keepalived 關閉，模擬服務故障

發現 VIP 192.168.159.200 切換到 備用服務器，訪問 192.168.159.120