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.

A project I’m working on currently requires me to build a server side agent daemon. Due to the nature of the agent, a live connection requires to be open to the managing node server, using websockets. PHP is not very well suited to this kind of workload, so the obvious choice was to develop it using NodeJS. I will build a Docker image containing the application, as well as provide a standalone binary for people who don’t have Docker, but also don’t want the hassle of installing NodeJS.

Setting up a testing environment can be a rewarding pursuit - if you do your testing before you deploy code, your tests can signal errors and stop you from deploying a critical mistake to production. Testing requires various software, depending on your development process. One of the most common php testing frameworks is phpunit. Let’s see how we can set up a Docker driven test environment.