双空间做域名跳转

server {
    listen 80;
    server_name primary-domain.com;

    location / {
        proxy_pass http://primary-server;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;

        # 健康检查
        health_check;
    }

    # 健康检查失败时跳转到备用域名
    location /health_check {
        proxy_pass http://primary-server/health_check;
        health_check;
    }

    # 健康检查失败时的重定向配置
    error_page 503 = @fallback;
}

server {
    listen 80;
    server_name fallback-domain.com;

    location / {
        proxy_pass http://fallback-server;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
}

# 健康检查失败时的重定向配置
map $upstream_http_status $redirect_to_fallback {
    default "";
    503 "http://fallback-domain.com$request_uri";
}

server {
    listen 80;
    server_name _;

    location / {
        proxy_pass http://primary-server;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;

        # 健康检查失败时重定向到备用域名
        if ($redirect_to_fallback) {
            return 302 $redirect_to_fallback;
        }
    }
}