Guide to deploy HAProxy

Introduction

Layman explanation

If you have contributed to open-source project ever, you may be aware about GitHub. GitHub is source version control where contributor uploads the code and users download the code. This GitHub can be very much loaded considering people throughout the world are accessing it. However, still we are able to access GitHub at reasonably fast speed. How this is possible? This is possible using software which balances load. HAProxy is such open source software..

Technical explanation

HAProxy is free, open source software that provides a high availability load balancer and proxy server for TCP and HTTP-based applications that spreads requests across multiple servers.

Deployment flavors

HAProxy can be deployed in Linux platform. For ubuntu, its easier to deploy using apt-get

Moreover, it can be deployed as Linux container (docker).

Deployment guide for non-docker setup

Install haproxy using apt-get:

Install HAproxy

apt-get install haproxy

We need to enable HAProxy to be started by the init script /etc/default/haproxy. Set ENABLED option to 1 as:

ENABLED=1

To verify if this change is done properly, execute the init script of HAProxy without any parameters. You should see the following:

$ service haproxy <press_tab_key>

reload restart start status stop

HAProxy is now installed.

Configuring HAProxy

/etc/haproxy/haproxy.cfg carries the configuration for haproxy. Note that in below sample, two backend servers are reachable via 10.102.53.233 and 10.102.169.145

Sample haproxy.cfg

global

log /dev/log local0

log /dev/log local1 notice

chroot /var/lib/haproxy

user haproxy

group haproxy

daemon

defaults

log global

mode http

option httplog

option dontlognull

contimeout 5000

clitimeout 50000

srvtimeout 50000

errorfile 400 /etc/haproxy/errors/400.http

errorfile 403 /etc/haproxy/errors/403.http

errorfile 408 /etc/haproxy/errors/408.http

errorfile 500 /etc/haproxy/errors/500.http

errorfile 502 /etc/haproxy/errors/502.http

errorfile 503 /etc/haproxy/errors/503.http

errorfile 504 /etc/haproxy/errors/504.http

frontend haproxy_in

bind *:80

default_backend haproxy_http

backend haproxy_http

balance roundrobin

mode http

server vm1 10.102.53.233:80 check

server vm2 10.102.169.145:80 check

To apply configuration, restart HAProxy daemon

Apply config

nsroot@ubuntu:~$ sudo service haproxy restart

* Restarting haproxy haproxy [ OK ]

nsroot@ubuntu:~$ service haproxy status

haproxy is running.

Testing HAProxy is straightforward. Here you need to perform http via web browser or using linux curl tool

from within the host ubuntu as shown in below example

Test output

nsroot@ubuntu:~$ curl http://localhost | less

% Total % Received % Xferd Average Speed Time Time Time Current

Dload Upload Total Spent Left Speed

100 11510 100 11510 0 0 1027k 0 --:--:-- --:--:-- --:--:-- 1124k

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<!--

Modified from the Debian original for Ubuntu

Last updated: 2014-03-19

See: https://launchpad.net/bugs/1288690

-->

<head>

<title>Apache2 Ubuntu Default Page: It works</title>

* {

Deployment guide for HAProxy as Docker

Pull HaProxy docker image

I assumed that docker is installed in your ubuntu box. If not, first deploy docker

Install HAProxy

root@ubuntu:~# docker images haproxy

REPOSITORY TAG IMAGE ID CREATED SIZE

haproxy latest 93e74258a04f 21 hours ago 139.1 MB

root@ubuntu:~# docker pull haproxy

Using default tag: latest

latest: Pulling from library/haproxy

8b87079b7a06: Already exists

a3ed95caeb02: Already exists

58acbe27a2eb: Already exists

0df18106ec05: Already exists

c7652a33f7e1: Already exists

Digest: sha256:4991df855175444e6ef3e8f04d093e8208bca65ca7b3ba75b6e3cfd44a8fe563

Status: Image is up to date for haproxy:latest

root@ubuntu:~# docker images haproxy

REPOSITORY TAG IMAGE ID CREATED SIZE

haproxy latest 93e74258a04f 21 hours ago 139.1 MB

Create HAProxy configuration file and host ubuntu machine (say, /home/haproxy/haproxy.cfg). This file carries the configuration for haproxy. Note that in below sample, two backend servers are reachable via 10.102.53.233 and 10.102.169.145

Sample haproxy.cfg

global

daemon

defaults

mode http

timeout connect 5000ms

timeout client 50000ms

timeout server 50000ms

frontend haproxy_in

bind *:80

default_backend haproxy_http

backend haproxy_http

balance roundrobin

mode http

server vm1 10.102.53.233:80 check

server vm2 10.102.169.145:80 check

Create HAProxy docker instance

HAProxy docker in host mode

[root@ubuntu /personal/]# docker run -dt -p 80 --net=host -v /home/haproxy/:/usr/local/etc/haproxy/:ro --name deepakk_haproxy_host haproxy

823490cb4def4601f11508fcc3f8a21cc5a0ae8edf29c63bdcc8d2b9ad5f1240

[root@ubuntu /personal/]# docker ps | grep deepakk_haproxy_host

823490cb4def haproxy "/docker-entrypoint.s" 9 seconds ago Up 8 seconds deepakk_haproxy_host

HAProxy docker in bridge mode

root@ubuntu:~# docker run -dt -p 1133:80 -v /home/haproxy/:/usr/local/etc/haproxy/:ro --name deepakk_haproxy haproxy

1d039a2239e4002d2c6fd43bb091b72bba595959e76d2b18a1819378c1057369

root@ubuntu:~# docker ps | grep deepakk_haproxy

1d039a2239e4 haproxy "/docker-entrypoint.s" 15 seconds ago Up 15 seconds 0.0.0.0:1133->80/tcp deepakk_haproxy

To see running haproxy

Check haproxy running

root@ubuntu:~# docker exec -it deepakk_haproxy /bin/bash

root@1d039a2239e4:/# ps -aef | grep haproxy

root 1 0 0 14:54 ? 00:00:00 /usr/local/sbin/haproxy-systemd-wrapper -p /run/haproxy.pid -f /usr/local/etc/haproxy/haproxy.cfg

root 12 1 0 14:54 ? 00:00:00 /usr/local/sbin/haproxy -p /run/haproxy.pid -f /usr/local/etc/haproxy/haproxy.cfg -Ds

root 13 12 0 14:54 ? 00:00:00 /usr/local/sbin/haproxy -p /run/haproxy.pid -f /usr/local/etc/haproxy/haproxy.cfg -Ds

root 25 14 0 14:56 ? 00:00:00 grep haproxy

Testing HAProxy is straightforward. Here you need to perform http via web browser or using linux curl tool

from within the host ubuntu as shown in below example

Sample test output

root@ubuntu:~# curl http://localhost:1133 | less

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<!--

Modified from the Debian original for Ubuntu

Last updated: 2014-03-19

See: https://launchpad.net/bugs/1288690

-->

<head>

<title>Apache2 Ubuntu Default Page: It works</title>

* {

margin: 0px 0px 0px 0px;

padding: 0px 0px 0px 0px;

}

body, html {

padding: 3px 3px 3px 3px;

background-color: #D8DBE2;

font-family: Verdana, sans-serif;

font-size: 11pt;

text-align: center;

}

div.main_page {

position: relative;

display: table;

width: 800px;

Config refresh

To refresh config, docker kill -s SIGHUP <HAProxy ID> is used

HAProxy configuration example with load balancing

HAProxy example with load balancing

root@ubuntu:~/docker-configs/haproxy/deepak# docker inspect 6646feac4834 | grep IP

"LinkLocalIPv6Address": "",

"LinkLocalIPv6PrefixLen": 0,

"SecondaryIPAddresses": null,

"SecondaryIPv6Addresses": null,

"GlobalIPv6Address": "",

"GlobalIPv6PrefixLen": 0,

"IPAddress": "",

"IPPrefixLen": 0,

"IPv6Gateway": "",

"IPAMConfig": {

"IPv4Address": "172.18.0.23"

"IPAddress": "172.18.0.23",

"IPPrefixLen": 16,

"IPv6Gateway": "",

"GlobalIPv6Address": "",

"GlobalIPv6PrefixLen": 0,

root@ubuntu:~/docker-configs/haproxy/deepak# cat config

defaults

mode http

timeout server 5s

timeout connect 5s

timeout client 5s

frontend frontend

bind *:1234

mode http

use_backend backend

backend backend

server s1 172.18.0.23:80 check

frontend monitoring

bind *:1235

no log

stats uri /

stats enable

root@ubuntu:~/docker-configs/haproxy/deepak# docker ps | grep 6646feac4834

6646feac4834 ubuntu:v1.2 "/bin/bash" 15 hours ago Up 15 hours 22/tcp, 80/tcp, 443/tcp, 161/udp, 0.0.0.0:3333->3333/tcp SRV

root@ubuntu:~/docker-configs/haproxy/deepak# curl -k http://172.18.0.23:80

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<!--

Modified from the Debian original for Ubuntu

Last updated: 2014-03-19

See: https://launchpad.net/bugs/1288690

-->

....

root@ubuntu:~/docker-configs/haproxy/deepak# curl -k http://localhost:1234

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<!--

Reference

https://en.wikipedia.org/wiki/HAProxy

https://docs.docker.com/samples/haproxy/

https://www.digitalocean.com/community/tutorials/how-to-use-haproxy-to-set-up-http-load-balancing-on-an-ubuntu-vps

https://www.howtoforge.com/tutorial/ubuntu-load-balancer-haproxy/

https://hub.docker.com/_/haproxy/