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Interview with Docker Captain Kendrick Coleman

“Docker doesn’t want to be replaced as the container runtime of choice”

Hartmut Schlosser
Docker
© Shutterstock / Julia Waller

How to get started in Docker? What issues do you experience when working with Docker? What is your favorite tip when using Docker? We talked with Kendrick Coleman, Docker Captain and Developer Advocate for {code} by Dell EMC about his experience with Docker and its disruptive nature. We actually asked a whole bunch of Docker Captains to share their Docker stories so stay tuned for more.

JAXenter: Can you tell us a little bit about your first contact with Docker? Was it love at first sight?

Kendrick Coleman: My first contact was watching a YouTube video. I didn’t get it. I had a very storied and deep relationship with virtualization and didn’t see how this would change. However, until I took an application I wrote and gave it a try, I realized immediately the benefit. It took my deployments from hundreds of MB in size down to tens. That’s when I gave up learning anything else about virtualization and went off the deep-end and took this next wave and met it head-on.

JAXenter: Docker is revolutionizing IT — that is what we read and hear very often. Do you think this is true? If we were to look beyond the hype, what’s so disruptive about Docker technology?

Kendrick Coleman: Docker is definitely revolutionizing IT. But right now, it’s not Docker alone. Docker has been the enabling technology that has not only burst them on the scene but other solutions that use Docker under the covers like Mesos and Kubernetes. These tools combined create a new and powerful tool for breaking down the wall between Devs and Ops.

The common packaging tool allows your application to be extremely portable between any environment whether it’s in the cloud, on-prem or between any orchestrator. The fact that this is completely open source does not mean it’s free. Nothing is ever free, remember that. Open Source means you must spend money in different ways through building your staff to learn something new, paid support, or consultation and outsourcing.

There is a misconception that persistent applications can’t or shouldn’t run in containers.

JAXenter: How is Docker different from a normal virtual machine?

Kendrick Coleman: We’ve all seen the comparison charts. For me, it’s speed and portability. After managing environments with hundreds of VMs, containers are going to reduce the footprint even further.

JAXenter: How do you use Docker in your daily work? 

Kendrick Coleman: Docker plays a role in my daily job. I am eager to learn the innards to find new corner cases. It makes me excited to know I can turn knobs to make applications work the way I want. There is a misconception that persistent applications can’t or shouldn’t run in containers. I’m proud that the team I work with builds tools to make running persistent application easy and seamless that can be integrated as a part of a toolchain.

JAXenter: What issues do you experience when working with Docker? What are the current challenges?

Kendrick Coleman: The amount of change is the biggest challenge. Open source technology moves at such a rapid pace that it’s incredibly hard to keep up with newer releases and the changes.

SEE ALSO: Top 10 Docker logging gotchas every Docker user should know

JAXenter: Talking about the evolution of the Docker ecosystem: How do you comment on Docker’s decision to donate containerd runtime to CNCF?

Kendrick Coleman: Docker’s decision to move containerd to CNCF and make a split between Moby is an attempt to keep their feet buried in the sand. Let’s not sugarcoat it. This is a really hot space with competition brewing and lots of leapfrogging.

Docker doesn’t want to be replaced as the container runtime of choice. containerd and Project Moby are attempts to allow new container packaging tools emerge but still share the underlying base functionality. This keeps Docker relevant because everyone will see the tool they created isn’t as simple as it sounds. This gives anyone the freedom to try and realize that Docker is the route of least resistance and to continue using their tool in lieu of something else, including rkt.

containerd and Project Moby are attempts to allow new container packaging tools emerge but still share the underlying base functionality. 

JAXenter: Is there a special feature you would like to see in one of the next Docker releases?

Kendrick Coleman: Working for a vendor introduces lots of challenges for our customers when the container orchestrator ecosystem doesn’t agree on a solution. Right now, storage and networking are the big challenges we face when our customers say “I want to use Docker Swarm” and someone else says “I want to use Kubernetes”.

Sure, Docker is the underlying technology but it goes beyond that when you move up the stack. This means, we as a vendor, have to create integrations with every orchestrator and continue the rigorous task of maintaining multiple pipelines of changes and communities. As a storage vendor, we are excited to see the Container Storage Interface (CSI) initiative grow. I would like to see Docker adopt this into their orchestrator to be on board with the rest of the ecosystem.

JAXenter: Could you share one of your favorite tips when using Docker?

Kendrick Coleman: Start off easy. Always go for the low-hanging fruit like a web server and make it work for you. Then take your single host and pick an orchestrator and use that to make your app resilient. After that, move to an application that uses persistent data. This allows you to progress and move all your applications off of VMs and into containers.

Thank you!

Author
Hartmut Schlosser
Hartmut Schlosser is an editor for JAXenter and a specialist in Java Enterprise-Technologies, Eclipse & ALM, Android and Business Technology. Before working at S&S Media he studied Computer Science, Music, Anthropology and French Philology.

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