A few weeks ago I wrote a short article, networking basics with docker. Since then, I’ve migrated my production environment to be docker only, and I’ve deployed 5 docker hosts which handle various tasks, from a production file server, search server with solr, my complete development environment and some websites (including this one!).

Over the course of a week I was hitting a few timeouts in connecting from one docker container to another, and finally, yesterday I consistently pinpointed a 4+ second delay on an API service I was writing. Four seconds. I’ll go over the steps that I took to diagnose and resolve the issue.

This is a story of how I learned to stop worrying and love the bomb. Well, it’s just about as iconic. Lone developer turns to Docker to set up a clean development environment as seamlessly as possible, including the bells and whistles of SSH agent forwarding. I’m pretty sure some of the folks on Docker HQ might have a small panic attack reading this one. Alas, I’m not a cardiac health professional.

If you run several docker containers, you might have already come to the requirement, that they talk to eachother via network. After all, your web application container should use your database container to store to and retrieve data from. This means, that in some way, your webserver container should talk to your database container.

It’s been more than a year in the waiting, after I found out that Mozilla Foundation, Akamai, Cisco, and a bunch of other big players put their support into LetsEncrypt, a free certificate authority. Back then (I’m speaking as if 2014 was still in the time of Yugoslavia or USSR), you would have to go trough several complicated steps for generating a SSL certificate for free (client certificates, issuing certificate signing requests, worrying about key size, key formats, validating your certificate via e-mail, …). I promise, the wait is over.

When setting up a development environment, eventually you’ll have to deal with migrating the services to another machine. Docker allows you to migrate docker images between servers, so you can take advantage of different VPS providers, more resources like memory, disk space, faster CPU or SSD drives.

The talk around the water cooler at startups is always around how much runway the startup has, and if the engineering talent will need to be searching for a new job any time soon. But running a startup is about more than money. And the problem gets harder if the people running it are funding it from other, more stable income, and their basic investment is time.