Does HAProxy support logging to a file?

Question

I've just installed haproxy on my test server.

Is there a way of making it write its logs to a local file, rather than syslog?

This is only for testing so I don't want to start opening ports / cluttering up syslog with all my test data.

Unfortunately, the only information I can find all revolves around logging to a syslog server.

I tried using:

log /home/user/ha.log local0

in my config. But that told me:

[ALERT] 039/095022 (9528) : sendto logger #1 failed: No such file or directory (errno=2)

When I restarted. So I created the file with touch /home/user/ha.log and restarted at which point I got:

[ALERT] 039/095055 (9593) : sendto logger #1 failed: Connection refused (errno=111)

Is this possible, or am I going to have to configure syslog etc. to see my test data?

Answer 1

Haproxy simply doesn't support logging to files. As stated in the documentation (https://cbonte.github.io/haproxy-dconv/1.8/configuration.html#3.1-log), the "log" statement takes as first parameter an address. If that's a file, it's a unix socket and HAProxy will speak in the syslog format to this socket. Haproxy is designed like this because its responsability is to proxy requests, not write files, it delegates writing of log files to syslog. If you don't want to mess with your machine, you can for example install logstash and run: logstash -e 'input { unix { path => "/tmp/haprxoy_log.sock" } } output { stdout { } }' and add: log /tmp/haprxoy_log.sock In your haproxy.cfg to test it.

Answer 2

You can change haproxy log config file under /etc/rsyslog.d/ to point the file to the path you like. Not sure about other distribution. For me, I'm using Debian. I changed /etc/rsyslog.d/49-haproxy.conf to point to /var/log/haproxy/haproxy.log,

# Create an additional socket in haproxy's chroot in order to allow logging via
# /dev/log to chroot'ed HAProxy processes
$AddUnixListenSocket /var/lib/haproxy/dev/log

# Send HAProxy messages to a dedicated logfile
:programname,startswith,"haproxy" /var/log/haproxy/haproxy.log

You should also update the log path in /etc/logrotate.d/haproxy to the new path. So that it will rotate and compress logfile in newly configured path using gzip.

Then restart rsyslog.service.

sudo systemctl restart rsyslog.service

Now haproxy.log.* file will be in /var/log/haproxy/ directory.

Answer 3

Since version 1.9 HAProxy supports logging to stdout and stderr.

With that in mind it's pretty trivial to pipe it to a file.

# change haproxy.cfg file with the following
global
    log stdout local0 debug

defaults
    log global
    option httplog

And then you can simply run HAProxy like this:

haproxy -f haproxy.cfg > haproxy.log 2>&1 &

As you probably know > pipes stdout to the file haproxy.log and then 2>&1 pipes stderr also to the same file. It ends with & that will put the process in the background.

You can get fancier and try to setup a script to kill the previous instance of haproxy by doing something like this:

#!/bin/bash
# mini launcher
kill -9 `cat /home/user/haproxy.pid`
/home/user/haproxy -f /home/haproxy.cfg > /home/user/haproxy.log 2>&1 &
echo $! > /home/user/haproxy.pid

Tough, as you can probably tell... not recommended.

Edit: Logging to files used to be a blocking event and thus, not recommended, specially for something like HAProxy. The HAProxy team made it abundantly clear on the release post linked above that this is not the case anymore.

We’ve received this request quite a bit and have spent some time planning the best way to implement it—without blocking—and we’re pleased to announce that we’ve found a solution!

Answer 4

You have tried to configured in the user home directory, haproxy doesn't have permission to access user's home directory, so that cause issue.

Instead try in other location, create directory in /var/<directory>

log /var/<directory>/ha.log

Answer 5

You will have to create a log service in order for haproxy to be able to log to specific files. Use following instructions, which worked for me in EL7 and HAProxy 2.7-dev5:-

yum install rsyslog

vi /etc/rsyslog.d/haproxy.conf

$ModLoad imudp
$UDPServerAddress 127.0.0.1
$UDPServerRun 514

local2.*        /logdir/haproxy
local3.*        /logdir/haproxy-access_log

systemctl restart rsyslog && ldconfig

vi /../../haproxy.cfg

global
        log stderr local0 info
        log 127.0.0.1 local2 notice
        log 127.0.0.1 local3

defaults 
        log global
        option httplog

systemctl restart haproxy

Don't forget to setup log rotation service as well, to avoid unnecessary space consumption and following should do the job:-

vi /etc/logrotate.d/haproxy

/logdir/logdir/haproxy-access_log {
  weekly
  rotate 7
  missingok
  size=5M
  notifempty
  dateext
  dateformat -%d%m%Y
  compress
  create 0644 logfileowner logfileowner
  su logfileowner logfileowner
  mail email@torecievelogs
  postrotate
    /usr/bin/systemctl reload haproxy
  endscript
}

Also, run the following two commands to find out if there is any problem with log rotation:-

logrotate --force /etc/logrotate.d/haproxy
grep logrotate /var/log/audit/audit.log | audit2why

Lastly, hereby I note if security-enhanced is enabled you might need to tweak log files context and its parent directory.

Good luck :).

Zakaria.