Alpine Linux containers

Hi,

I wanted to share some initial findings with the community. I am a part of the Flockport team. Flockport provides ready to deploy containers of popular web apps. I have been curious about Alpine and was having a look at it.

There are a number of interesting decisions the Alpine developers have made. It's lightweight, network oriented and security focused. All these makes it an excellent host for VMs and containers and due to its lightweight nature also an excellent VM and container OS.

LXC is an open source project and part of the kernel, that uses cgroups and namespaces to create lightweight OS environments, so you could be running a Debian host and multiple Ubuntu, Fedora, Centos or Alpine containers and vice versa.

Containers are isolated from the host system, give you near bare-metal performance and are portable, so you can have a minimal host and have your apps in containers that are portable across Linux hosts.

The LXC project provides container management tools and lightweight container OS templates. There are templates for Debian, Ubuntu, Centos, Fedora and there is even a nice minimalist Alpine Linux one.

Flockport uses LXC to provide prebuilt containers of apps like Wordpress, Discourse, Redmine, Drupal etc even a multi-domain mail server. These containers have the stack ie mysql, php, nginx and the apps installed and ready to launch.

We have been using Debian as the base our containers and also Ubuntu for the 32 bit ones. The base containers are around 200MB uncompressed and once you install the stack and apps they end up around 600MB for the Wordpress container and around 1.5GB for the Discourse container (with build environment, Ruby etc) We use XZ to compress the containers for distribution and they end up in the range of 120MB to 330MB compressed.

Yesterday I tried to create a number of Alpine Linux containers and here are the results. The Alpine Linux Nginx container is 14MB uncompressed and only 3.5MB compressed! In contrast the Nginx container based on Debian Wheezy is around 337MB uncompressed and 72MB compressed.

The Wordpress container based on Alpine Linux is around 155MB uncompressed and only 27MB compressed! The Wordpress Debian container is around 619MB uncompressed and around 130MB compressed.

Those are huge differences in size and bandwidth for us and users. A container needs a lightweight execution environment and Alpine makes perfect sense both as the host, and as a container. But of course its more than us just shipping it, users have to be familiar with Alpine Linux and know how to use it. I just wanted to put this out there.