perl

Fixing Common Perl Issues – cPanel

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Sometimes you’ll notice that a certain function of cPanel or WHM was working fine, now all of a sudden you’re getting results that you’ve never seen before. Believe it or not, many problems with cPanel functionality related to processes running off of scripts is because of a perl corruption. To resolve this, usually the first step you should take is running a cPanel update, as this will correct most issues. If the problem persists, you may need to recompile perl from it’s core.

Before we start, here are a few of the most common indicators that there is a perl issue on your server:

  • Accounts are not created properly, like missing files
  • Frontpage extensions refuse to be installed
  • Stats won’t run, result in cryptic perl errors
  • Error messages that look like this:
(internal death) Sat Jun 3 21:01:55 2006 [32719] error: List::Util object version 1.14 does not match
 bootstrap parameter 1.18 at /usr/lib/perl5/5.8.7/i686-linux/XSLoader.pm line 92.
==> Starting cpbandwd (bandwidth monitoring for IMAP/POP)
Can't locate Class/Std.pm in @INC (@INC contains: /usr/local/cpanel /usr/lib/perl5/5.8.7/i686-linux
/usr/lib/perl5/5.8.7
BEGIN failed--compilation aborted at /usr/lib/perl5/site_perl/5.8.7/Unix/PID.pm line 8.
Compilation failed in require at /usr/local/cpanel/bin/cpbandwd line 15.
BEGIN failed--compilation aborted at /usr/local/cpanel/bin/cpbandwd line 15.

In some cases, the error is specific about a perl module missing. If this is the case, look for the perlmod format in the error message. In the above example you can see ‘List::Util’ being referenced, so you can try to reinstall that either manually or from WHM:

/scripts/perlinstaller –force List::Util

If reinstalling the perl module itself does not solve the problem, you can recompile perl. First, do a perl -v from command line to see what version you are running. Then follow these steps:

wget http://layer1.cpanel.net/perl587installer.tar.gz
tar xvzf perl587installer.tar.gz
cd perl587installer
./install

/usr/local/cpanel/bin/checkperlmodules

If you are running 5.8.8, use the installer from:

http://layer1.cpanel.net/perl588installer.tar.gz

The recompile may take as long as 20 minutes to complete.

Downgrading MySQL to 4.x – cPanel

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If you’ve upgraded MySQL via WebHost manager, the downgrade process is slightly more complex than the upgrade. This tutorial mainly covers a downgrade from 4.1 to 4.0, but also applies to downgrading from 5.x to 4.x.

*Back up all databases before proceeding, as all existing databases will be deleted!

1. Uninstall existing MySQL packages:

rpm -qa | grep -i mysql-

This should return a list of several rpm’s installed. You will need to remove them all with the rpm -e command .

2. Delete the active MySQL directory:

rm -Rfv /var/lib/mysql

3. Get cPanel Ready

Edit /var/cpanel/cpanel.config and change the version to the one that you are downgrading to (4.0, 4.1, etc)

mysql-version=4.0

Make sure that MySQL updates aren’t being skipped:

rm /etc/mysqldisable
rm /etc/mysqlupdisable

4. Install MySQL:

/scripts/mysqlup –force

5. Update the perl module:

/scripts/perlinstaller –force Bundle::DBD::mysql

Finally, recompile Apache and PHP via Web Host Manager.

Wrong Version Numbers in cPanel

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It’s common that when moving a cPanel account between servers with differing software versions, the version numbers (specifically MySQL) on the side of cPanel still reflect those of the old server. This can be changed by editing the version files for the account that was moved:

The files holding the version numbers are located in:

cpanel 10: /home/username/.cpanel-datastore/

cpanel 11: /home/username/.cpanel/datastore/

The following files control the version display in user cPanels:

Apache Version:

_usr_local_apache_bin_httpd_-v

Perl Version:

_usr_bin_perl_-v

MySQL Version:

_usr_sbin_mysqld_–version