Fixing Perl Downgrade Issues in CPanel/WHM

Woke up this morning to find an inbox full of error emails, a queue full of emails pending and a server with a very well broken system install that was stopping CPanel & WHM from working properly. Errors that appeared when trying to load pages in WHM included:

• /bin/sh: line 1:  8621 Segmentation fault      /usr/local/cpanel/whostmgr/bin/dnsqueue > /dev/null 2>&1
• Premature end of script headers: /usr/local/cpanel/whostmgr/docroot/cgi/easyapache.pl: Please check  /usr/local/cpanel/logs/error_log for the exact error.Internal Error: “GET /cgi/easyapache.pl?action=_pre_cpanel_sync_screen HTTP/1.1″ Premature end of script headers: /usr/local/cpanel/whostmgr/docroot/cgi/easyapache.pl: Please check /usr/local/cpanel/logs/error_log for the exact error.

Anyhow, the sweet and the short of it was that in the nightly build from RELEASE CPanel had managed to backgrade my version of Perl and as a result everything was completely miss-configured. To this end, I came across these wonderful instructions on the CPanel forums that helped fix the problem sharpish:

1. Kill any rogue upcp process
2. /scripts/fixeverything
3. wget http://layer1.cpanel.net/perl588installer.tar.gz
4. tar xfvz perl588installer.tar.gz
5. cd perl588installer
6. ./install
7. /usr/local/cpanel/bin/checkperlmodules
8. /scripts/upcp –force
9. /etc/init.d/cpanel restart

After you have run this you will likely have to import any cached sql queries that both tailwatchd/eximstats were unable to put into mysql whilst the server was in a broken state, but CPanel kindly provides instructions for this too:

1. mv /var/cpanel/sql/eximstats.sql /var/cpanel/sql/eximstats.sql.tmp_working_copy
2. /usr/local/cpanel/libexec/tailwatchd –restart
3. mysql eximstats < /var/cpanel/sql/eximstats.sql.tmp_working_copy
4. rm /var/cpanel/sql/eximstats.sql.tmp_working_copy

The original forum post is here.