confd and Docker - Separating config and code for containers

This repo contains an example of how to use confd with Docker environment variables in order to set run-time configuration for containers. A full blog post is available here

This example uses nginx. The following occurs when launching a new container.

• the container bootstrap script /start.sh executes. It validates required environment variables and sets defaults where required.
• confd executes and creates 2 configuration files in /etc/nginx/conf.d based on templates and environment variables.
• nginx gets launched.

The 2 configuration files created are for a simple reverse proxy and for a simple load balancer. They are only intended as an example of what's possible with confd and environment variables.

Getting started

Create the required docker image.

docker build nginx-confd .

Run the container with the required environment variables. In this instance, $proxy_domain, $backend_host, $load_balancer_domain and $app_servers.

docker run -it -p 80:80 -e proxy_domain="awesome.app.local" \
-e backend_host="app01.domain.local" \
-e load_balancer_domain="myapp.local" \
-e app_servers="myapp01.local:myapp02.local:myapp03.local:myapp04.local" \
nginx-confd