From Debian to CoreOS


Tags: coreos docker debian caddy rkt

Moving to CoreOS

Just a quick entry here. Historically this site has been running on a Digital Ocean Debian droplet. I liked having a remote Linux host that I could run random things on, including this blog.

However, recently I’ve only been using it to run things within Docker containers. Since CoreOS was designed for exactly this purpose, I decided to try setting up a single-host cluster as a DO droplet. It was super-easy to set this up as a replacement for the old Debian host. And I even went as far as automating the container set up with cloud-config userdata1. Now if I need to replace this host for whatever reason, I’ll just spin up a new one with the same userdata. Easy-peasy.

Future Changes

One thing I had to change with my Docker container was to have Caddy use CloudFlare to create an SSL cert. I’d rather use Let’s Encrypt, but when I was testing it I was impatient with how quickly the IP needed to be changed, and since it’s behind CloudFlare anyway, it was an easy fix. I’ll have to figure out a better way to keep using Let’s Encrypt and replacing hosts in the future.

I also wanted to try using rkt instead of Docker to run my containers. The fact that there are less layers between systemd and the running container is appealing. Unfortunately, there’s a bug with docker2aci that drops things like setting limits or adding capabilities.2 The container I’m using runs as a non-root user, and I didn’t want to have to change that just to switch to rkt. Once that bug is addressed, I’ll definitely give it another go.