A website hosted in Plesk periodically shows the Plesk/web server default page or old website content

Symptoms

• A website periodically shows the Plesk default page, web server’s default page or old website content.

• Pages of the website may not load with the error:

  PLESK_INFO: 404 Not Found

Cause

Apache runs child processes (workers) to process connections that are established to a website. Some workers may hang during reload process causing the content to be served with old data. The first process is “master” and it will show the date when Apache have been started. Check the rest of child processes and if one of them has date of start much older than others, that means it is hanged. See an example below: 

# ps uaxf | grep [a]pache
root     723810 0.0  0.5 194584 144184  ? Ss Apr07 3:06  /usr/sbin/apache2 -k start
www-data 723811 0.0  0.5 193308  140564 ? Sl May10 36:00  _ /usr/sbin/apache2 -k start
www-data 723812 0.0  0.5 194484  140108 ? S  10:39 0:00   _ /usr/sbin/apache2 -k start
www-data 725215 13.1 0.6 2128208 158620 ? Sl 10:47 0:55   _ /usr/sbin/apache2 -k start

Resolution

1. Connect to the Plesk server via SSH.

2. Stop the Apache process:

   • on CentOS/RHEL-based distributions

     # service httpd stop

   • on Debian/Ubuntu-based distributions

     # service apache2 stop

3. Check if there are any hung processes with the command:

   # ps uaxf | grep [a]pache

   If the output is non-empty:

   root 8637 0.0 0.2 287780 46124 ? Ss Jun26 0:55 /usr/sbin/apache2 -k start
   www-data 8927 0.0 0.2 286504 43968 ? S Jun26 0:00 /usr/sbin/apache2 -k start
   www-data 8928 0.0 0.2 287696 44424 ? S Jun26 0:46 /usr/sbin/apache2 -k start

   kill these processes using their PID:

   # kill -9 8637 8927 8928

4. Start the Apache process:

   • on CentOS/RHEL-based distributions

     # service httpd start

   • on Debian/Ubuntu-based distributions

     # service apache2 start