Why Docker?

During 15+ in the IT Infrastructure field, I moved from bare-metal machines to VMs and now surfing in the cloud (Azure and AWS) in both IaaS and PaaS worlds.. but installing and configuring applications require always manual steps to be performed that can result in configuration drifting especially some time after the first setup.

Configuration drift: phenomenon whereby small, sometimes gradual, changes to software and hardware creates unknowable differences across environments. For example, a production server may ‘drift’ so that what works in development may no longer work in production. Some production-only failures can be caused by configuration drift.

First time I was trying to find a solution for this (and others like better agility, faster process to get the application up & running, better horizontal/vertical scalability), I came out finding a project called Docker. It was late 2014… And it was only related with Linux eco-system. As I was working 99% of the time with Microsoft OS and applications.. well.. I just gave up at that time.

Then in 2016, Microsoft started to contribute with Docker in the Docker Team (with Google, RedHat and IBM) and announced that Docker would be integrated in the next version of Windows Server.. Great!

Today, Docker and Containers Orchestrators are fully integrated with the cloud: In Azure new WebApps are basically based on Docker (and Kubernetes) and companies are starting to adopt it for DevOps projects.

So, last year, I started to think at the docker certification as a think that could help me with my career (requests for Docker and Kubernetes Professional are increased exponentially in the last 2 years).

So I started to prepare for the exam to certify my professional skills on Docker.

The Objective

Docker offers a certification (DCA – Docker Certified Associate) and, to get it, you need to pass an exam (55 questions in 90 minutes) remotely proctored on your Windows or Mac computer. there is no fix passing score published as this can change based on the questions you get. 

The Preparation

I’m a Microsoft guy.. bash was not my friend (CMD and PowerShell are part of my day-by-day tasks) so I started from what I knew:

  1.  Getting Started with Docker on Windows (Wes Higbee) – PluralSight – Simple and clear course on Docker basics on Windows! This gave me an idea of the entire docker architecture, bricks names and a nice playground in a well-known environment.. Also Docker for Windows 10 permits to run Windows Containers but also Linux containers on a MobyLinux VM fully managed by the Docker installation.. amazing!
  2. Docker Certified Associate Prep Course (Terrence Cox) – Linux Academy – Starting going out from the comfort zone here. Docker installed on Ubuntu and CentOS (including Swarm as orchestrator). A lot of technical information, a lot exercises and the best playground labs experience.
  3. Learn Docker by Doing (Travis Thomsen) – Linux Academy – Just pure and dirty hands-on challenges. Here you can really learn a lot beyond the theory. This course includes also an introduction on Kubernetes that is not required for the Docker certification.
  4. Docker Documentation – I used that to deep dive on some topic I would like to be more familiar with.

The Exam Day

The exam is planned to be 90 minutes for 55 questions (all multiple choice). You need to be alone in the room with nothing except your laptop. They will control you through the webcam. With my experience and preparation, I completed the exam in 16 minutes and 43 seconds with 96% aggregate score. The result will come in your mailbox just in few hours (check the spam folder.. my result was there!). In term of complexity, I found it quite easy: the multiple choice questions make the challenge easy as the docker commands are exactly the same in Windows and Linux (pay attention only on at volume mounting questions).



Now, it’s time for Certified Kubernetes Administrator Certification.. and I let you know how it is as soon as I complete all the training on Linux Academy (this exam is ALL hand-on on Linux..)


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