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Last pushed: 5 days ago
Short Description
Serve multiple docker containers with the help of haproxy and a small python script
Full Description

dockerized haproxy

this docker container provides haproxy and a small python script which will recreate its configuration from available docker hosts when the file /tmp/haproxy gets changed

How does it work

haproxy is listening on port 80 and will forward all requests to a specific docker-image. It uses the hostname to distinguish the containers.

How does haproxy know about the running docker-containers? There's a python script based on work of Bastian Hoyer which rewrites the haproxy-configuration on request. It will scan all running docker-containers and get the hostname and port from all running containers via environment-variables. The container set the environment-variable VHOST and (optionally) VPORT to their needs, the configuration utility parses this information and the internal IP of the docker-container and constructs a suitable haproxy-configuration file and restarts haproxy.

If you want to recreate the haproxy-configuraion just touch /tmp/haproxy, the script will rewrite the configuration and restart haproxy.

Environment variables used by haproxy_config:

  • VHOST or VIRTUAL_HOST the hostname to use for this docker-container
  • VPORT or VIRTUAL_PORT the port to forward the http-traffic to, defaults to 80
  • SSL a path to a ssl-certificate to use for HTTPS-traffic
  • HTTPS_ONLY will forward traffic for port 80 to port 443 for that given VHOST.
  • REDIRECT_FROM redirect from a given hostname.
  • SSH if a container exposes this environment variable, all ssh-traffic to 22 is forwarded to the container. This setting can be used only for one container.


running this docker-command will instruct haproxy to forward all https traffic for my.domain.tld to port 8888 inside the container

docker run \
  -e VHOST=my.domain.tld \
  -e VPORT=8888 \
  -e SSL=/etc/ssl/private/mycert.pem \
  -e HTTPS_ONLY=1 \
  -e REDIRECT_FROM=old.domain.tld \

This will instruct haproxy forward all http and https traffic for my.domain.tldto port8888insidemydocker-container. It will also redirect all traffic forold.domain.tldtomy.domain.tld`

Pull the container via

docker pull factorial/haproxy-config

Build the container locally

docker build --tag=factorial/haproxy-config .

Run the container

docker run \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -v /tmp:/tmp \
  -v /dev/log:/dev/log \
  -p 80:80 \
  -p 1936:1936 \
  --name haproxy \
  -d \

Note: if you want that haproxy handles SSL-traffic, you'll need to map the correspondig directory into the haproxy-container and listen also on port 443.

Docker networks

With version 1.1.0 docker networks are supported, Please make sure, that the haproxy container can connect to the networks of your docker-container:

docker network connect haproxy <your-network-name>



  • support for docker networks
  • support for VIRTUAL_HOST and VIRTUAL_PORT
  • support for forwarding SSH-traffic to a specific container


  • bind also to port 8080


  • enhance documentation
  • fix race condition of spawning multiple haproxy instances


  • initial release
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