David Currie

Last night I headed up to London for the December meetup of Docker London. The evening didn’t get off to a great start as I managed to cycle over a screw on the way to the station. Despite this, and the subsequent efforts of the Jubilee Line, I did just make the start in time.

The evening kicked off with Chad Metcalf from Docker demoing Tutum. It was just a slight variant of one of the demos from DockerCon so nothing really new for me here although he did talk a little about the extensions to the Compose syntax that Tutum uses. The HIGH_AVAILABILITY strategy being something that’s obviously missing from Compose/Swarm today.

Next up was Alois Mayr, a Developer Advocate at Ruxit, who did a nice job of not explicitly pushing his company’s offering but instead talked more generally about some issues experienced by a Brazillian customer of theirs that has a large deployment of Docker running on Mesos. The underlying theme was undoubtedly that, in a large microservices based architecture, you need to have a good understanding of the relationships between your services and their dependencies in order to be able to track problems back to the root cause.

Last up was an entertaining pitch by Chris Urwin, an engineering lead at HSCIC (part of the NHS) and consultant Ed Marshall. They talked about a project to move from a Microsoft VMM (and Excel spreadsheet) based setup to one using Docker and Rancher for container management. They were undoubtedly pleased with the outcomes in terms of developer productivity and the manageability of the deployed environment, not to mention reduction in cost and complexity. Although the system is not live in production yet, it is live in an environment that they share with partners that is subject to SLAs etc. Particularly striking for me was the reduction in the amount of disk space and memory that the new solution entailed.

I picked up a copy of Docker in Production – Lessons from the Trenches during a recent O’Reilly sale, hoping to pick up some tips to pass on to customers that I work with. I have to say that I was disappointed! It’s not that the book isn’t full of useful information. It is. After a good start, it just failed to deliver on the title for me.

After covering the basics and the likely areas of concern, it introduces an example with the wise words that not everyone is looking to deploy a platform for running tens of thousands of containers and that even small deployments can benefit from their use. The example describes a simple environment using systemd to stand up a static topology with the ability to provide environment specific configuration. Just the sort of concrete material I was hoping for.

The next couple of chapters provided further examples from a second company: one using a simple scripted approach and another using AWS Beanstalk. So far, so good. At this point the book changed tack though and switched to covering different subject areas such as security, building and storing images, configuration management, networking, scheduling, service discovery, and concluding with logging and monitoring. Although, as I say, there was lots of good information scattered throughout, these chapters somehow felt like they were just giving an overview of the current state of the Docker ecosystem without giving much in the way of guidance as to how to select from the myriad of options to create a production-ready solution.

Perhaps I’m being unfair and this is simply a reflection on the current state of play. Whilst the Docker feature set is still being fleshed out there are still many compromises to be made and over time we may see more repeatable deployment patterns emerging. The fact that much of the material in the book was not new to me is probably a reflection of the efforts I am taking to keep up with what is a rapidly transforming area.

One final thought: it will be interesting to contrast this book with the free eBooks series that The New Stack has just begun. The first book, entitled “The Docker and Container Ecosystem”, includes some interesting metrics to suggest who are the main players. The catalogue of services and projects that form the second half of the book is truly eye-watering and whilst it can be seen as an indicator of vibrancy, it does indicate a real need to be able to provide guidance to those who do not have the time or inclination to immerse themselves in this world.