What Is Docker & How Does It Simplify Software Testing?
Test Automation
Sripathi Krishnasamy July 5, 2023

Today, Docker has become a game-changer in the tech world. It’s an open-source platform that makes software testing and deployment a breeze.

So, what’s the big deal about Docker? Well, imagine having a magic box that contains everything your software needs to run smoothly. That’s what Docker does! It simplifies testing and makes it easier to manage applications and their dependencies.

In this article, we’ll explore why Docker creates waves, how it simplifies test automation, and how ThinkPalm uses it to streamline our testing process. 

What’s Docker?

Docker is an open-source software platform that revolutionized containerization technology. In simple terms, it can be called a software tool that helps people build and run applications more easily. Also, it uses a special technology called “containerization” to create small, isolated environments called containers where applications can run. 

These containers include everything the application needs to work, like the code, tools, and other software it relies on. Docker makes it easier to package applications and move them between different computers, so they work the same way no matter where they’re run. This software development and deployment tool was created by Docker Inc. in 2013 and has become very popular because it’s efficient and easy to use.

How Does Docker Work?

Docker works by packaging applications and their dependencies into containers, which are self-contained units. Each container runs on the same underlying operating system (OS) and shares its services. Docker images contain all the necessary components to execute code within a container, ensuring that containers work seamlessly when moved between Docker environments within the same OS. How does Docker Work?

Unlike virtual machines, Docker uses resource isolation in the OS kernel to enable multiple containers to run on the same OS. Initially designed for Linux, Docker has expanded its support to include non-Linux operating systems like Windows and macOS, and there are Docker versions available for cloud platforms such as Amazon Web Services (AWS) and Microsoft Azure.

What are the Key Components of Docker?

1. Docker Engine

The ‘Docker Engine’ is the main part of Docker and consists of the following components:

  • Docker Application: Installed on your computer, it serves as the heart of the Docker system.
  • Server (Daemon): A long-running program that handles Docker operations. It runs in the background, managing containers and executing commands.
  • REST API: Docker provides a set of interfaces called the REST API, which allows other programs to communicate with the Docker daemon and give instructions.
  • Command-Line Interface (CLI) Client: The “docker” command is used through the command-line interface to interact with Docker. It allows users to issue commands and manage Docker containers efficiently.

What are the Key Components of Docker?In simple terms, Docker Engine is like the brain of Docker. It has a server that does the work, an API that helps other programs talk to it, and a command-line interface that allows users to control Docker using commands.

2. Docker Image

Think of it as a template used to create Docker Containers. It’s like a snapshot of an application that can be shared and used by others. Docker Images are created using the “build” command and are read-only.

3. Docker Container

It’s a running instance of a Docker Image. Containers are like self-contained packages that hold everything needed to run an application. They are created using the “run” command and can be easily started, stopped, or moved around.

4. Docker Registry

This is where Docker Images are stored. It can be a local repository or a public repository like Docker Hub. It allows users to share and collaborate on building applications. Docker Hub is a popular public repository.

5. Docker Architecture

The Docker Architecture consists of three main components:

  • Docker Client: It sends commands to Docker and interacts with the Docker system.
  • Docker Host: This is where the Docker Daemon runs. It manages the images and containers.
  • Docker Registry: It stores Docker Images, which can be either a public repository like Docker Hub or a local repository.

Here’s how it works:

  • We use the Docker Client (CLI) to send a build command to the Docker Daemon running on the Docker Host to build a Docker Image. The Docker Daemon then builds the image based on the provided inputs and saves it in the Registry.
  • If we don’t want to create our image, we can pull an existing image from the Docker Hub, which might have been built by someone else and stored in the Registry.
  • Finally, to run an instance of a Docker image, we use the CLI to issue a run command. This will create a Docker Container based on the image, allowing us to use and interact with the application inside.

Docker Architecture

6. Docker Compose

It helps run multiple Docker Containers as a single server. For example, if you need WordPress, Maria DB, and PHP MyAdmin, you can define them in one file and start them together. Also, it’s useful for managing applications with multiple components.

7. Docker Swarm

It provides clustering functionality for Docker containers. Also, it allows multiple Docker engines to work together as a single virtual Docker Engine. Moreover, it simplifies the management of containerized applications.

What’s the Role of Docker in Testing?

Docker makes testing easier by simplifying the setup and execution of test environments. In addition, it provides containers that contain everything needed for testing, so testers can quickly set up and run tests without complicated configurations.

Real time example: we can easily install the required packages for each feature on containers.

Docker also allows parallel testing by creating multiple containers, which improves efficiency. Also, testers can ensure everyone uses the same setup, reducing variations and potential issues. Moreover, it promotes collaboration among team members by enabling the sharing of test environments.

Real time example: we can run multiple browsers for Selenium testing by creating multiple containers.

Additionally, Docker integrates seamlessly with CI/CD pipelines, enabling automated testing and deployment. Overall, Docker simplifies the testing process, maintains consistency, and supports efficient collaboration and automation.

Did you know

As shown in the below diagram, the tester can create a customized server to run multiple containers simultaneously and divide their tests among them.

Diagram: the tester can create a customized server to run multiple containers simultaneously and divide their tests among them.

How We Use Docker to Succeed?

At ThinkPalm, Docker is a unique tool that helps us achieve remarkable feats. 

There are two main ways we use Docker: one is for setting up Jenkins slave nodes, and the other is for managing Jenkins pipelines. Let’s see how Docker makes everything easier for us:

1. No Additional Tools Required

Instead of installing lots of extra tools, ThinkPalm can simply use ready-made images from Docker Hub. Also, Jenkins can easily find and download these images from the internet.

2. Saving Resources

Docker is smart about using resources. Moreover, it only creates Jenkins slave nodes when they are needed, so resources are not wasted when they are not being used.

3. Quick and Easy Provisioning

Docker is lightweight, which means it can set up Jenkins slave containers really fast and without any trouble. Therefore, reputed software development firms, such as ThinkPalm, can efficiently leverage the benefits of Docker. Moreover, Docker’s lightweight nature enables these esteemed organizations to set up Jenkins slave containers swiftly and effortlessly. This capability empowers ThinkPalm to expand our Jenkins cluster seamlessly whenever the need arises.

4. Same Everywhere

Docker makes sure that everything is the same across different deployments. This means that ThinkPalm can easily make copies of our Jenkins slave nodes with all the same settings and things we need to work properly.

5. Scalable and Flexible

At ThinkPalm, Docker helps us handle different amounts of work. If we have lots of work to do, Docker can quickly make more Jenkins slave nodes to handle it. Similarly, if we have less work, Docker can reduce the number of nodes. This helps us work efficiently and not waste any resources.

Also Read: Jenkins for Continuous Integration and Deployment

6. Safe and Secure

Docker keeps things separate and safe. Similarly, each Jenkins slave node runs in its own special place, so there’s no chance of things getting mixed up or causing problems. Also, this keeps data safe and private.

Expanding Horizons with ThinkPalm: Discover the Power of Containers and Docker

Containers and Docker have the potential to unleash innovative possibilities for industries and enterprises. At ThinkPalm, we specialize in leveraging the power of Docker to drive business success. If you want to learn more about how Docker can help your business thrive, contact us today. Our team of experts is here to assist you on this transformative journey.

Wrapping Up

At ThinkPalm, we have harnessed Docker’s power to transform our operations and achieved remarkable results. From dynamic provisioning of Jenkins slave nodes to streamlining our test automation services, Docker has revolutionized how we work.

Moreover, Docker’s isolation and security features provide a safe environment for executing jobs, safeguarding data privacy, and minimizing conflicts. Our test automation services have been supercharged with Docker, allowing us to deliver high-quality solutions with speed and precision.

If you want to experience the benefits of Docker and enhance your test automation processes, our experts are here to help. Contact us today and let our team guide you towards unlocking the full potential of Docker in your organization.

Test automation services ThinkPalm


Author Bio

Sripathi Krishnasamy is an experienced QA tester with more than 12 years of expertise in Storage, Networking, SD-WAN, and Python/Golang automation. He currently holds the position of Senior Technical Lead at ThinkPalm. Sripathi possesses extensive knowledge of Python and Golang frameworks and actively assists newly onboarded freshers in their Python/Golang journey.