Ubuntu14.04下Apache2部署的PHP5文件间歇性无法运行求助

Hey there, let's tackle this frustrating intermittent issue with your main.php file. It's tricky when something works sometimes and not others, but we can break it down step by step to find the root cause:

1. Check Apache & PHP Error Logs #

Logs are your best friend for intermittent problems—they’ll usually show what’s failing when the issue pops up.

• Apache Error Log: Run tail -f /var/log/apache2/error.log in a terminal to stream logs in real-time. Then refresh localhost/main.php a few times (both when it works and fails) and watch for error messages like permission denied, PHP module crashes, or resource limits.
• PHP Error Log: By default, PHP might not show errors on the page. Edit your PHP config file at /etc/php5/apache2/php.ini:
  • Set display_errors = On and error_reporting = E_ALL
  • Look for the error_log line to find where PHP logs are stored (usually /var/log/php5/apache2.log)
  • Restart Apache with sudo service apache2 restart and test again—you might see errors directly on the page now.

2. Verify File Permissions & Ownership #

Odd permissions can sometimes cause intermittent issues (especially if other processes are modifying the file). Check your main.php file:

• Run ls -l /var/www/html/main.php to see permissions and ownership.
• Ensure the file is readable by the Apache user (www-data). Fix permissions with:

  sudo chown www-data:www-data /var/www/html/main.php
  sudo chmod 644 /var/www/html/main.php
  

3. Check PHP-FPM Stability (If Used) #

Ubuntu 14.04 often uses PHP-FPM with Apache. If the FPM process crashes or hangs, it can cause intermittent failures:

• Check FPM status: sudo service php5-fpm status
• Restart FPM to rule out a stuck process: sudo service php5-fpm restart
• Check FPM logs for errors: tail -f /var/log/php5-fpm.log

4. Confirm Apache PHP Module & Config #

Make sure Apache is properly configured to parse PHP:

• Verify the PHP5 module is loaded: apache2ctl -M | grep php5 (you should see php5_module (shared)). If not, enable it with sudo a2enmod php5 and restart Apache.
• Check your default site config (/etc/apache2/sites-available/000-default.conf)—ensure the /var/www/html directory block has:

  <Directory /var/www/html>
      Options Indexes FollowSymLinks MultiViews
      AllowOverride All
      Order allow,deny
      allow from all
  </Directory>
  

  This ensures Apache can parse PHP files in that directory.

5. Test a Minimal PHP File #

Rule out issues with your main.php code by creating a simple test file:

• Create /var/www/html/test.php with:

  <?php
  echo "PHP is working!";
  phpinfo();
  ?>
  

• Visit localhost/test.php multiple times. If this works consistently, the problem is likely in your main.php code—check for things like unhandled MySQL connection timeouts, race conditions, or conditional code that fails under certain circumstances (e.g., missing variables, file I/O errors).

6. Check System Resources #

Intermittent failures can also stem from system resource limits:

• Run top or htop to monitor CPU and memory usage while testing main.php. Look for spikes or processes being killed.
• Check system logs for out-of-memory (OOM) events: grep -i "out of memory" /var/log/syslog—if the OOM killer is terminating Apache/PHP processes, you’ll need to free up memory or adjust system limits.

If none of these steps resolve the issue, share the error messages from your Apache/PHP logs or snippets of your main.php code (especially parts involving MySQL or file operations) and we can dig deeper.

内容的提问来源于stack exchange，提问作者alhelal