Docker is a popular containerization platform that has been used by developers and teams to build and scale containerized applications. However, many non-technical professionals are unaware of its capabilities, or why Docker is such a popular choice.
In the following article, we are going to do a deep dive into Docker, and explain why it is so popularly adopted and used.
What is Docker?
At its core, Docker is simply a containerization platform that’s available open-source. For those who don’t know, containerization simply refers to packaging software code using simply the libraries of the operating system and the dependencies needed to run the code.
It’s all packaged in a single, lightweight “container”, allowing consistent execution on any kind of infrastructure. Containers are preferred by developers instead of virtual machines (VMs) because they are more portable and can be used for running modern cloud-based applications.
Docker makes it easy for developers to create containers, making the process for building, managing, and deploying containers incredibly straightforward. Think of it as a toolkit that lets you manage containers using a single, straightforward API.
Here are some other reasons why Docker is so popular:
- It simplifies infrastructure management
- Ideal for building and sharing disk images
- It can be used to maintain a centralized repository of all disk images
For instance, while you write code in Java and run it using a JVM, you can create a Dockerfile and deploy it on a Docker server.
And, like Git, Docker makes the same promises, except you can track changes in systems, instead of changes in code. Docker lets you track changes throughout your entire system, letting you pull history to see all recent updates.
We already made an entire post on what Docker is, so if you want to know more details about it, make sure to check our post here.
Why Use Docker?
So, now that you understand the basics, let’s talk about the many reasons why so many dev teams and technical professionals prefer Docker over other options, such as Kubernetes or Microsoft Azure Container Registry.
One of the main reasons why Docker is such a preferred choice for dev teams is because it adds a layer of security that developers don’t get if they build outside of Docker. For starters, you get the option of separating individual components of a larger application into separate containers.
This way, should a single container become compromised, you won’t have to worry about the effect permeating through the rest of the application. With distributed teams working on different components, additional security is always good.
2. Version and Environment Control
Docker has the ability to track discrete versions of container images. This gives you unprecedented version control, letting you roll back to a previous iteration, view past-built versions, including developers who worked on them, and how the work was done.
More importantly, you can also decide to upload exclusively just the changes that were highlighted between an existing version of a container and the new version.
If your software runs in different environments, there’s also a risk of identifying inconsistencies in behavior depending on the machine or environment that the software runs on.
For instance, one element that works on a developer’s computer might not work on a specific server, which would be a new environment.
However, since Docker lets you isolate software in containers, you can run them separately without having to worry about environmental changes.
3. Identical Code Reproduction
One of the biggest advantages of Docker is its ability to reproduce code in an identical fashion on any system, as long as it is capable of running Docker. Just like Java apps, which tend to run in the same way as long as the machine supports Java VM, Docker containers can do the same.
You can view the exact specifications of different containers using their Dockerfiles. This way, when working in teams, you can guarantee that all software images that are built using the same Dockerfile will function the same way.
And, having consistent code documentation is obviously going to make it easier for you to identify issues and track your application development in a better manner.
4. Isolated Environment
This one links with additional security. Since the dependencies of one container don’t affect other installations on the container or other containers, developers can prevent any kind of conflicts between dependencies.
For instance, you can use separate containers for front-end development or for servers. This makes it easy for dev teams to run multiple projects on the same server, without having to worry about any conflicting dependencies.
5. Easy Technology Management
Docker makes it incredibly easy to manage new technologies and to test them out. If you’re interested in trying out new programming languages or new databases, you can easily do so. The Docker Hub has a fantastic collection of ready-to-use docker images.
Just search for a relevant Docker image, and you’re good to go. You can seamlessly add it to your existing Docker configuration. This helps teams save a great deal of time that would otherwise be spent on debugging or installing new images.
When To Use Docker
Not sure about when Docker might be useful for your development? We’ve put together a range of situations to give you a better idea about when to use Docker.
1. When Running Orchestration Engines Like Kubernetes
While it’s easy to manage a handful of containers directly from the Docker Engine, things do become a bit confusing when your software deployment includes thousands of containers and several services.
That’s why you might want to consider using an orchestration engine, such as Kubernetes. Container orchestration tools such as Kubernetes are incredibly powerful and are the preferred choice for most developers.
Docker does have its own orchestration engine, entitled Docker Swarm, though Kubernetes far outranks it in terms of popularity.
It helps automate several tasks associated with containerized architectures. This makes it incredibly easy to run multiple servers and even lets you deploy your services on several new services.
2. Ideal for Implementing Version Control
As stated above, Docker containers make it easy for you to standardize the environment and speed up software development cycles. For instance, if you perform an upgrade on a specific component that ends up breaking the entire environment, you can easily roll back to a previous Docker image.
Docker is much faster than conventional VM backups, allowing you to quickly replicate the changes and launch new Docker images.
3. When You Have Developers Working In Different Setups
Development teams tend to change quite frequently. It’s always a bit time-consuming when you are onboarding new developers to an existing project. Before they can start writing code, you need to make sure that they have a local development environment set up.
Depending upon the project complexity, this can take quite a bit of time, especially when you have to add third-party libraries and databases too. Docker simplifies this process, virtually automating it to the point where developers just have to run a single command, and Docker will do the rest.
This way, not only do you save a great deal of time, but it also allows you to activate new team members from the first day.
4. Isolating Apps
Developers tend to add new libraries, dependencies, and services to software on a daily basis. This tends to get more complex over time, which is why it’s important for you to make sure that you keep track of all parts, and above all, prevent the software from breaking.
Docker lets you isolate apps or settings within specific containers so that they won’t affect other installations or instances of apps running on the same system.
5. When You Want to Move Away From Amazon AMI Marketplace or the Warden Project
There are a couple of alternatives available to Docker, including the Amazon AMI Marketplace, which is arguably the closest substitute. However, the problem with AMIs is that they run exclusively on Amazon.
That’s not the issue with Docker, since you can run it on any Linux server, as long as it supports Docker. More importantly, Docker container services also work on Amazon EC2 (Elastic Compute Cloud).
Another option is the Warden Project, which was written for Cloud Foundry. However, Docker again wins in this field as it contains more social options, letting developers share images with others who are on the same Docker Index.
After Action Report — Docker Is Application Development Standard
Docker is a fantastic choice in most cases, but it’s not always the best choice. For instance, while Docker’s a fantastic choice for web apps, it’s not viable if you’re developing a desktop application. While you can build such apps on Docker, it’s generally not the natural environment for running apps that have rich GUIs.
All in all, Docker’s a fantastic open-source platform that greatly helps development teams streamline workflows and manage development more effectively.
Have you worked with Docker before? What are your thoughts on it? Let’s discuss in the comments!