Ubuntu 18.x下Apache2添加子域并实现HTTPS转发的问题

你的问题出在主域配置冲突和子域配置的潜在疏漏上：

1. 主域80端口存在两个ServerName example.com的VirtualHost，Apache会优先匹配第一个规则，当子域请求未被正确匹配时，会被主域的跳转逻辑强制导向www.example.com。
2. 子域配置可能存在格式错误，或Apache未正确加载子域站点配置。

1. 修复主域HTTP（80端口）配置 #

打开example.com.conf，合并重复的VirtualHost，简化规则：

<VirtualHost *:80>
    ServerAdmin info@example.com
    ServerName example.com
    ServerAlias www.example.com
    DocumentRoot /var/www/example.com/public_html
    ErrorLog ${APACHE_LOG_DIR}/example.com.error.log
    CustomLog ${APACHE_LOG_DIR}/example.com.access.log combined

    RewriteEngine on
    # 处理example.com跳转到www.example.com并强制HTTPS
    RewriteCond %{SERVER_NAME} =example.com
    RewriteRule ^ https://www.example.com%{REQUEST_URI} [END,NE,R=permanent]
    # 处理www.example.com直接跳转到HTTPS
    RewriteCond %{SERVER_NAME} =www.example.com
    RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} [END,NE,R=permanent]
</VirtualHost>

删除原来第一个单独的Redirect VirtualHost，避免规则冲突

2. 修正子域HTTP配置 #

确保development.example.com.conf配置逻辑正确（子域无需跳转到www）：

<VirtualHost *:80>
    ServerAdmin info@example.com
    ServerName development.example.com
    DocumentRoot /var/www/development.example.com/public_html
    ErrorLog ${APACHE_LOG_DIR}/development.example.com.error.log
    CustomLog ${APACHE_LOG_DIR}/development.example.com.access.log combined

    RewriteEngine on
    # 仅强制子域跳转到HTTPS
    RewriteCond %{SERVER_NAME} =development.example.com
    RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} [END,NE,R=permanent]
</VirtualHost>

3. 修正子域HTTPS配置 #

打开development.example.com-le-ssl.conf，确保配置正确且证书覆盖子域：

<IfModule mod_ssl.c>
<VirtualHost *:443>
    ServerAdmin info@example.com
    ServerName development.example.com
    DocumentRoot /var/www/development.example.com/public_html
    ErrorLog ${APACHE_LOG_DIR}/development.example.com.error.log
    CustomLog ${APACHE_LOG_DIR}/development.example.com.access.log combined
    Include /etc/letsencrypt/options-ssl-apache.conf
    # 确保证书路径正确，且证书包含development.example.com（通配符证书或单独申请的子域证书）
    SSLCertificateFile /etc/letsencrypt/live/development.example.com/fullchain.pem
    SSLCertificateKeyFile /etc/letsencrypt/live/development.example.com/privkey.pem
</VirtualHost>
</IfModule>

4. 启用子域站点并重启Apache #

执行以下命令完成配置加载：

# 启用子域HTTP站点
a2ensite development.example.com.conf
# 启用子域HTTPS站点
a2ensite development.example.com-le-ssl.conf
# 检查Apache配置语法
apache2ctl configtest
# 重启Apache服务
systemctl restart apache2

5. 验证DNS解析 #

确认development.example.com的DNS记录已正确指向服务器IP，避免因解析错误导致请求落到主域配置上。

• 若问题仍存在，检查并禁用Apache默认站点（000-default.conf），避免默认站点接管未匹配的请求：

  a2dissite 000-default.conf
  systemctl restart apache2
  

• 查看Apache错误日志（/var/log/apache2/error.log），排查是否有子域配置加载失败或证书相关错误。

内容的提问来源于stack exchange，提问作者spreaderman