Easy HAProxy

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This Docker image will create dynamically the haproxy.cfg based on the labels defined in docker containers or from a simple Yaml instead docker


  • Enable or disable Stats on port 1936 with custom password
  • Discover and setup haproxy from Docker Tag
  • Discover and setup haproxy redirect from Docker Tag
  • Setup HAProxy CFG from a Yaml file.

Basic Usage

The Easy HAProxy will create the haproxy.cfg automatically based on the containers or from a YAML provided.

The basic command line to run is:

docker run -d \
    --name easy-haproxy-container \
    -v /var/run/docker.sock:/var/run/docker.sock \
    -e DISCOVER="swarm|docker|static" \
    # + Environment Variables \
    # + ports mapped to the host \

The mapping to /var/run/docker.sock is necessary to discover the docker containers and get the labels;

The environment variables will setup the HAProxy.

Environment Variable Description
DISCOVER How haproxy.cfg will be created: static, docker or swarm
HAPROXY_USERNAME (Optional) The HAProxy username to the statistics. Default: admin
HAPROXY_PASSWORD The HAProxy password to the statistics. If not set disable stats.
HAPROXY_STATS_PORT (Optional) The HAProxy port to the statistics. Default: 1936
HAPROXY_CUSTOMERRORS (Optional) If HAProxy will use custom HTML errors. true/false. Default: false

The environment variable DISCOVER will define where is located your containers (see below more details):

  • docker
  • swarm
  • static

Automatic Discover Services

Easy HAProxy can discover automatically the container services running in the same network of Docker or in a Docker Swarm cluster.

DISCOVER: docker

This method will use a regular docker installation to discover the containers and configure the HAProxy.

The only requirement is that containers and easy-haproxy must be in the same docker network.

The discover will occur every minute.


docker create networkd easyhaproxy

docker run --network easyhaproxy byjg/easyhaproxy

docker run --network easyhaproxy myimage


This method requires a functional Docker Swarm Cluster. The system will search for the labels in all containers on all swarm nodes.

The discover will occur every minute.

Important: easyhaproxy needs to be in the same network of the containers or otherwise will not access.

Tags to be attached in the Docker Container (Swarm or Docker)

Tag Description Example
easyhaproxy.definitions A Comma delimited list with the definitions. Each name requires the definition of the parameters below. service,service2
easyhaproxy.mode.[definition] (Optional) Is this http or tcp mode in HAProxy. (Defaults to http) http
easyhaproxy.port.[definition] (Optional) What is the port that the HAProxy will listen to. (Defaults to 80) 80
easyhaproxy.localport.[definition] (Optional) What is the port that the container is listening. (Defaults to 80) 8080
easyhaproxy.host.[definition] What is the host that the HAProxy will listen to. somehost.com
easyhaproxy.redirect.[definition] (Optional) Host redirects from connections in the port defined above. foo.com–https://bla.com,bar.com–https://bar.org
easyhaproxy.sslcert.[definition] (Optional) Cert PEM Base64 encoded.  
easyhaproxy.health-check.[definition] (Optional) ssl, enable health check via SSL in mode tcp (Defaults to "empty")  

Defining the labels in Docker Swarm

if you are deploying a stack in a Docker Swarm cluster set labels at the deploy level:

         easyhaproxy.definitions: "service1,service2"

Single Definition:

docker run \
    -l easyhaproxy.definitions=webapi \
    -l easyhaproxy.port.webapi=80\
    -l easyhaproxy.host.webapi=byjg.com.br \

Multiples Definitions on the same container:

docker run \
    -l easyhaproxy.definitions=express,admin \

    -l easyhaproxy.port.express=80 \
    -l easyhaproxy.localport.express=3000 \
    -l easyhaproxy.host.express=express.byjg.com.br \

    -l easyhaproxy.port.admin=80 \
    -l easyhaproxy.localport.admin=3001 \
    -l easyhaproxy.host.admin=admin.byjg.com.br \
    .... \

TLS passthrough

Used to pass on SSL-termination to a backend:

docker run \
    -l easyhaproxy.defintions=example \
    -l easyhaproxy.mode.example=tcp \
    -l easyhaproxy.health-check.example=ssl \
    -l easyhaproxy.port.example=443
    .... \
  • enable health-check via SSL on the backend with the optional health-check label

Redirect Example:

docker run \
    -l easyhaproxy.redirect.<defintion>=www.byjg.com.br--http://byjg.com.br,byjg.com--http://byjg.com.br

DISCOVER: static

This method expects a YAML file to setup the haproxy.cfg

Create a YAML file and map to /etc/haproxy/easyconfig.yml

  username: admin
  password: password
  port: 1936         # Optional (default 1936)

customerrors: true   # Optional (default false)

  - port: 80
      host1.com.br: container:5000
      host2.com.br: other:3000
      www.host1.com.br: http://host1.com.br

  - port: 443
    ssl_cert: /path/to/ssl/certificate
      host1.com.br: container:80

  - port: 8080
      host3.com.br: domain:8181


docker run -v /my/config.yml:/etc/haproxy/easyconfig.yml .... byjg/easyhaproxy

Mapping custom .cfg files

Map a folder containing valid HAProxy .cfg files to /etc/haproxy/conf.d. It will be concatenated to your HAProxy CFG.

docker run \
    /* other parameters */
    -v /your/local/conf.d:/etc/haproxy/conf.d \
    -d byjg/easy-haproxy

Handling SSL

You can attach a valid SSL certificate to the request.

  1. First Create a single PEM file including CA.
cat example.com.crt example.com.key > single.pem

cat single.pem


  1. Convert it to BASE64 in a single line:
cat single.pem | base64 -w0
  1. Use this string to define the label easyhaproxy.sslcert.[definition]

Setting Custom Errors

If enabled, map the volume : /etc/haproxy/errors-custom/ to your container and put a file named ERROR_NUMBER.http where ERROR_NUMBER is the http error code (e.g. 503.http)


docker build -t byjg/easy-haproxy .

Open source ByJG