How do I use HAProxy with environment variables when running as service

Question

I am new to Linux and are trying to configure HAProxy with environment variables. I am running Debian 8 (Jessie) and HAProxy 1.5.8 that I installed using apt-get as per https://haproxy.debian.net/#?distribution=Debian&release=jessie&version=1.5

Without environment variables the configuration works excellent.

I followed the instructions from this answer (setting the environment variable from /etc/init.d/haproxy)to get environment variables working but still got the 503 - Service Unavailable response.

I then looked through /etc/init.d/haproxy and thought that these two lines maybe changed the scope of what variables were available

[ -f /etc/default/rcS ] && . /etc/default/rcS . /lib/lsb/init-functions 

so I commented them out.

I can then start HAProxy using sudo /etc/init.d/haproxy startand my configuration works as I expect but when I try to run sudo service haproxy start I still get the 503 - Service Unavailable.

It seems to me like this question has the answer I'm looking for but I have not been able to translate the answers from there to my domain.

This is the part of the haproxy.cfg file where I'm using environment variables:

backend backend1 server EnvVar ${SERVER_IP}:86 maxconn 512 

I have also looked through some other questions here without finding a solution to my problem.

How do I set an environment variable so that it can be read by haproxy when haproxy is run as a service?

Answer 1

I finally figured it out.

In /lib/systemd/system/haproxy.service there is a line like this

EnvironmentFile=-/etc/default/haproxy 

I looked in /etc/default/haproxy and this is what it looks like:

# Defaults file for HAProxy # # This is sourced by both, the initscript and the systemd unit file, so do not # treat it as a shell script fragment. # Change the config file location if needed #CONFIG="/etc/haproxy/haproxy.cfg" # Add extra flags here, see haproxy(1) for a few options #EXTRAOPTS="-de -m 16" 

I added my environment variable there and reverted the rest of my changes and it works both when running as a service and when running it directly using /etc/init.d/haproxy.

This is the line I added:

SERVER_IP=165.88.76.44 

Answer 2

This answer is right and works correctly on haproxy 1.7 - 1.8

Here a simple script to improve use for multiple haproxy files :

cd /etc/sysconfig for i in haproxy_*; do echo $i; echo "MY_SERVER=$(hostname -i)" >> $i done 

Now in Haproxy settings :

... backend lochttps server server_name ${MY_SERVER}:60441 check ssl verify none id 1 ...