In its default config, HAProxy send logs to a syslog facility: local0, via a socket connection. By default, your syslog configuration probably doesn’t accept socket connections, and even doesn’t have a local0 facility, so you have no HAProxy log. If you want it, configure syslog to accept TCP connections by adding -r to syslogd parameters.

On a RedHat/CentOS server, edit the value of SYSLOGD_OPTIONS in /etc/sysconfig/syslog:

SYSLOGD_OPTIONS="-m 0 -r"

On a Debian/Ubuntu server, edit the value of SYSLOGD in /etc/default/syslogd:

SYSLOGD="-r"

Then set up syslog facility local0 and direct it to file /var/log/haproxy.log or your desired location by editing /etc/syslog.conf:

local0.* /var/log/haproxy.log

finally, restart syslog service to apply changes:

$ /etc/init.d/syslog restart

You can see that HAProxy logging is started.

Other useful article on this blog that you may like to read:
* Configure HAProxy for content switching
* 5 Steps to secure your Production Linux Server
* Ensuring secure access to your Production Linux Server
* Bash script to backup essential log files in Linux Server

Undefined subroutine &LWP::Debug::trace called at /usr/lib/perl5/site_perl/5.8.8/LWP/UserAgent/Determined.pm line 21.

Force Re-installation of LWP::UserAgent::Determined module does not avail anything.

Then after some research, I came to know that the perl libwww-perl version 5.822 is culprit here. And the strange thing is that the updated version (5.822) causes problems while downgraded version (5.821) works fine. This bug is already reported here.

To quickly fix the error, download and install 5.821 version:

$ wget http://search.cpan.org/CPAN/authors/id/G/GA/GAAS/libwww-perl-5.821.tar.gz
$ tar xzf libwww-perl-5.821.tar.gz
$ cd libwww-perl-5.821
$ perl Makefile.PL
$ make
$ make install

The issue has been resolved.

You may also like to read:
* 5 steps to secure your Linux Server
* Ensuring secure access to production Linux Servers
* Bash script to backup essential log files in Linux
* Quickly change your ssh port from defualt 22 to something higher
* SSH port forwarding from remote to local machine
* Save root or user history to check later
* Install and configure denyhost to prevent brute force attacks

500 OOPS: vsf_sysutil_recv_peek

The solution for this problem is to load capability module:

$ modprobe capability

You may also like to read:
* 5 steps to secure your Linux Server
* Ensuring secure access to production Linux Servers
* Bash script to backup essential log files in Linux
* Quickly change your ssh port from defualt 22 to something higher
* SSH port forwarding from remote to local machine
* Save root or user history to check later
* Install and configure denyhost to prevent brute force attacks