dekobon/bouncy-haproxy repository overview

⁠Bouncy HAProxy

This Docker image aims to overcome some of the shortcomings of the official HAProxy image. Understandably, the official image needs to conform to general standards that may be at odds with an operationalized image. This image differs in the following ways:

⁠Differences Between library/haproxy

1. It is using phusion-base image in order to run as a multi-process Docker container.
2. It is running a syslog daemon and cron in order to properly handle log output from HAProxy because HAProxy doesn't support a production-ready stand-alone mode that outputs logs to STDOUT.
3. It provides a default volume so that your configuration can be persisted even if you remove this container.
4. It supports restarting HAProxy without shutting down the container. Since HAProxy needs to have the old PIDs shutdown in order reload the configuration this often results in HAProxy exiting entirely and thereby ending the container management process (PID 1). This makes bouncing the load balancer configuration very difficult.
5. The multi-process model on this container will allow those who want to extend it to be able to write their own processes that monitor an endpoint or a DOCKER_HOST and then modify the configuration. Next, they can then bounce HAProxy and have a new server pool loaded.

⁠Setup Hints

1. You probably want to mount a data volume on /etc/haproxy/config in order to make your HAProxy configuration persistance across reboots.
2. You will need to modify the default configuration file /etc/haproxy/config/haproxy.cfg to conform to your particular setup.
3. If you add servers inside of the ### start/end pool ### comment block you can use utilities to template in linked servers into your configuration.
4. Take a look at update-lb-pool.sh for an example of a script that you could run from a machine configured with a DOCKER_HOST variable. This script will allow you to update your haproxy.cfg to include all hosts that match a given prefix (as is predictably created by docker-compose). For example, you could add all instances of your site container by doing: ./update_lb_pool.sh cluster_site 80 cluster_haproxy_1

⁠Runtime Hints

1. You can reload the proxy configuration at runtime by running the script: /usr/local/bin/bounce_haproxy