我已经在 Centos 8 上安装了 Apache 2.4 和 PHP 7.4，它在 Google Cloud Platform 上运行。
阿帕奇：
● httpd.service - The Apache HTTP Server
Loaded: loaded (/usr/lib/systemd/system/httpd.service; disabled; vendor preset: disabled)
Drop-In: /usr/lib/systemd/system/httpd.service.d
└─php-fpm.conf, php74-php-fpm.conf
Active: active (running) since Wed 2020-07-29 07:55:37 UTC; 41min ago
Docs: man:httpd.service(8)
Main PID: 20366 (httpd)
Status: "Total requests: 19; Idle/Busy workers 100/0;Requests/sec: 0.0076; Bytes served/sec: 63 B/sec"
Tasks: 278 (limit: 9312)
Memory: 35.4M
CGroup: /system.slice/httpd.service
├─20366 /usr/sbin/httpd -DFOREGROUND
├─20368 /usr/sbin/httpd -DFOREGROUND
├─20369 /usr/sbin/httpd -DFOREGROUND
├─20370 /usr/sbin/httpd -DFOREGROUND
├─20371 /usr/sbin/httpd -DFOREGROUND
└─20583 /usr/sbin/httpd -DFOREGROUND
Jul 29 07:55:37 test-app-devel1 systemd[1]: Stopped The Apache HTTP Server.
Jul 29 07:55:37 test-app-devel1 systemd[1]: Starting The Apache HTTP Server...
Jul 29 07:55:37 test-app-devel1 systemd[1]: Started The Apache HTTP Server.
Jul 29 07:55:37 test-app-devel1 httpd[20366]: Server configured, listening on: port 443, port 80
PHP的：
php --version
PHP 7.4.8 (cli) (built: Jul 9 2020 08:57:23) ( NTS )
Copyright (c) The PHP Group
Zend Engine v3.4.0, Copyright (c) Zend Technologies
with Zend OPcache v7.4.8, Copyright (c), by Zend Technologies
直接使用php命令运行 PHP 脚本没问题。问题是无法通过浏览器执行 PHP 文件。我收到此 503 错误：
服务不可用 由于维护停机或容量问题，服务器暂时无法满足您的请求。请稍后重试。
以下是来自 Apache 日志的一些当前条目：
xxx.xxx.xxx.xxx - - [29/Jul/2020:08:15:17 +0000] "GET /test.txt HTTP/1.1" 304 - "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.105 Safari/537.36"
xxx.xxx.xxx.xxx - - [29/Jul/2020:08:15:19 +0000] "GET /test.txt HTTP/1.1" 304 - "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.105 Safari/537.36"
xxx.xxx.xxx.xxx - - [29/Jul/2020:08:15:32 +0000] "GET /ASF20thAnniversary.jpg HTTP/1.1" 200 72242 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.105 Safari/537.36"
xxx.xxx.xxx.xxx - - [29/Jul/2020:08:15:41 +0000] "GET /phpinfo.php HTTP/1.1" 503 299 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.105 Safari/537.36"
xxx.xxx.xxx.xxx - - [29/Jul/2020:08:16:01 +0000] "-" 408 - "-" "-"
txt 和 jpg 文件均已正确加载。但 php 文件却加载不了。如何修复此问题？