I recently ran into problems on my web server and during the troubleshooting process I realized that I did not know everything I needed to know. As the issue was related to the "Web Host Manager / Cpanel" software application I had troubleshoot the application a little bit. I was able to fix the problem and gained some valuable knowledge. Here are some quick tips for troubleshooting WM and Cpanel. Please assure that you have root or admin rights to the server and access to the server via SSH.
Restart WHM/Cpanel
Logon to the server via SSH and switch to the root user. Execute the following command to restart WHM/Cpanel and all related services:
/etc/rc.d/init.d/cpanel restart
This command fixed an issue where the daily log file update job had stopped working and users complained that the web statistics were not updating anymore. Before I tried restarting WHM/Cpanel I wanted to be sure that the actual update process of the web logs would still be working. I found the following command (executed from the command line via SSH) very helpful. It updates the web logs for the statistic applications (Webalizer, Urchin, AWStats) per user account:
/scripts/runweblogs username
Of course going this route can be cumbersome if you have to update more than just a few domain accounts.
Sometimes it can be helpful to manually update WHM/Cpanel with a newer version. In my situation this fixed an issue where "Eximstats" had stopped working and showed a red warning light in WHM. I felt more confident going through the command line/SSH to update WHM/Cpanel in this case. As great as the 'GUI' tool for administering your server is - sometimes the good old command line is just more appealing to the get the job done. To force an update of WHM/Cpanel run the following from the command line logged in as the root user:
/scripts/upcp --force
If you experience problems restarting Apache from WHM - try to restart it from the command line (as root user). From my full-time job I can access my server on WHM only by going through a proxy. For whatever reason - I am not able to restart Apache in WHM when going through the proxy. So, it is very helpful that I still have SSH access and can restart Apache that way. Use the following command to restart Apache via SSH:
/etc/init.d/httpd restart
If your server experiences high loads in spikes it can often be either MySQL or Exim that uses too many resources (CPU cycles). Check what processes use more CPU compared to normal levels. With Exim I found it a working quick fix to just restart the service from WHM/Cpanel itself.
Sure, there are many more things you will need for troubleshooting when running into problems. Please check back soon as we will add more technical papers to the Web Hosting Resource Kit soon.
