Containers might seem like a relatively recent technological breakthrough, but their origins trace back to the 1970s when Unix systems first used container-like concepts to isolate applications. Fast-forward to 2013, and Docker revolutionized this idea by introducing a portable, user-friendly container platform, sparking widespread adoption. In 2015, Docker was instrumental in creating the Open Container Initiative (OCI) to promote open standards within the container ecosystem. With the stability provided by the OCI, container technology spread throughout the tech world.

Although Docker Desktop is the leading tool for creating containerized applications, Docker remains surrounded by numerous misconceptions. In this article, we’ll debunk the top Docker myths and explain the capabilities and benefits of this transformative technology.

Myth #1: Docker is no longer open source

Docker consists of multiple components, most of which are open source. The core Docker Engine is open source and licensed under the Apache 2.0 license, so developers can continue to use and contribute to it freely. Other vital parts of the Docker ecosystem, like the Docker CLI and Docker Compose, also remain open source. This allows the community to maintain transparency, contribute improvements, and customize their container solutions.

Docker’s commitment to open source is best illustrated by the Moby Project. In 2017, Moby was spun out of the then-monolithic Docker codebase to provide a set of “building blocks” to create containerized solutions and platforms. Docker uses the Moby project for the free Docker Engine project and our commercial Docker Desktop.

Users can also find Trusted Open Source Content on Docker Hub. These Docker-Sponsored Open Source and Docker Official Images offer trusted versions of open source projects and reliable building blocks for better development.

Docker is a founder and remains a crucial contributor to the OCI, which defines container standards. This initiative ensures that Docker and other container technologies remain interoperable and maintain a commitment to open source principles.

Myth #2: Docker containers are virtual machines 

Docker containers are often mistaken for virtual machines (VMs), but the technologies operate quite differently. Unlike VMs, Docker containers don’t include an entire operating system (OS). Instead, they share the host operating system kernel, making them more lightweight and efficient. VMs require a hypervisor to create virtual hardware for the guest OS, which introduces significant overhead. Docker only packages the application and its dependencies, allowing for faster startup times and minimal performance overhead.

By utilizing the host operating system’s resources efficiently, Docker containers use fewer resources overall than VMs, which need substantial resources to run multiple operating systems concurrently. Docker’s architecture efficiently runs numerous isolated applications on a single host, optimizing infrastructure and development workflows. Understanding this distinction is crucial for maximizing Docker’s lightweight and scalable potential.

However, when running on non-Linux systems, Docker needs to emulate a Linux environment. For example, Docker Desktop uses a fully managed VM to provide a consistent experience across Windows, Mac, and Linux by running its Linux components inside this VM.

Myth #3: Docker Engine vs. Docker Desktop vs. Docker Enterprise Edition — They’re all the same

Considerable confusion surrounds the different Docker options that are available, which include:

• Mirantis Container Runtime: Docker Enterprise Edition (Docker EE) was sold to Mirantis in 2019 and rebranded as Mirantis Container Runtime. This software, which is managed and sold by Mirantis, is designed for production container deployments and offers a lightweight alternative to existing orchestration tools.
• Docker Engine: Docker Engine is the fully open source version built from the Moby Project, providing the Docker Engine and CLI.
• Docker Desktop: Docker Desktop is a commercial offering sold by Docker that combines Docker Engine with additional features to enhance developer productivity. The Docker Business subscription includes advanced security and governance features for enterprises.

All of these variants are OCI-compliant, differing mainly in features and experiences. Docker Engine caters to the open source community, Docker Desktop elevates developer workflows with a comprehensive suite of tools for building and scaling applications, and Mirantis Container Runtime provides a specialized solution for enterprise production environments with advanced management and support. Understanding these distinctions is crucial for selecting the appropriate Docker variant to meet specific project requirements and organizational goals.

Myth #4: Docker is the same thing as Kubernetes

This myth arises from the fact that both Docker and Kubernetes are associated with containerized environments. Although they are both key players in the container ecosystem, they serve different roles.

Kubernetes (K8s) is an orchestration system for managing container instances at scale. This container orchestration tool automates the deployment, scaling, and operations of multiple containers across clusters of hosts. Other orchestration technologies include Nomad, serverless frameworks, Docker’s Swarm mode, and Apache Mesos. Each offers different features for managing containerized workloads.

Docker is primarily a platform for developing, shipping, and running containerized applications. It focuses on packaging applications and their dependencies in a portable container and is often used for local development where scaling is not required. Docker Desktop includes Docker Compose, which is designed to orchestrate multi-container deployments locally

In many organizations, Docker is used to develop applications, and the resulting Docker images are then deployed to Kubernetes for production. To support this workflow, Docker Desktop includes an embedded Kubernetes installation and the Compose Bridge tool for translating Compose format into Kubernetes-friendly code.

Myth #5: Docker is not secure

The belief that Docker is not secure is often a result of misunderstandings around how security is implemented within Docker. To help reduce security vulnerabilities and minimize the attack surface, Docker offers the following measures:

Opt-in security configuration 

Except for a few components, Docker operates on an opt-in basis for security. This approach removes friction for new users, but means Docker can still be configured to be more secure for enterprise considerations and for security-conscious users with sensitive data.

“Rootless” mode capabilities 

Docker Engine can run in rootless mode, where the Docker daemon runs without root permissions. This capability reduces the potential blast radius of malicious code escaping a container and gaining root permissions on the host. Docker Desktop takes security further by offering Enhanced Container Isolation (ECI), which provides advanced isolation features beyond what rootless mode can offer.

Built-in security features

Additionally, Docker security includes built-in features such as namespaces, control groups (cgroups), and seccomp profiles that provide isolation and limit the capabilities of containers.

SOC 2 Type 2 Attestation and ISO 27001 Certification

It’s important to note that, as an open source tool, Docker Engine is not in scope for SOC 2 Type 2 Attestation or ISO 27001 Certification. These certifications pertain to Docker, Inc.’s paid products, which offer additional enterprise-grade security and compliance features. These paid features, outlined in a Docker security blog post, focus on enhancing security and simplifying compliance for SOC 2, ISO 27001, FedRAMP, and other standards.  

Along with these security measures, Docker also provides best practices in the Docker documentation and training materials to help users learn how to secure their containers effectively. Recognizing and implementing these features reduces security risks and ensures that Docker can be a secure platform for containerized applications.

Myth #6: Docker is dead

This myth stems from the rapid growth and changes within the container ecosystem over the past decade. To keep pace with these changes, Docker is actively developed and is also widely adopted. In fact, the Stack Overflow community chose Docker as the most-used and most-desired developer tool in the 2024 Developer Survey for the second year in a row and recognized it as the most-admired developer tool. 

Docker Hub is one of the world’s largest repositories of container images. According to the 2024 Docker State of Application Development Report, tools like Docker Desktop, Docker Scout, Docker Build Cloud, and Docker Debug are integral to more than two-thirds of container development workflows. And, as a founding member of the OCI and steward of the Moby project, Docker continues to play a guiding role in containerization.

In the automation space, Docker is crucial for building OCI images and creating lightweight runners for build queues. With the rise of data science and AI/ML, Docker images facilitate the exchange of models, notebooks, and applications, supported by GPU workload capabilities in Docker Desktop. Additionally, Docker is widely used for quickly and cost-effectively mocking up test scenarios as an alternative to deploying actual hardware or VMs.

Myth #7: Docker is hard to learn

The belief that Docker is difficult to learn often comes from the perceived complexity of container concepts and Docker’s many features. However, Docker is a foundational technology used by more than 20 million developers worldwide, and countless resources are available to make learning Docker accessible.

Docker, Inc. is committed to the developer experience, creating intuitive and user-friendly product design for Docker Desktop and supporting products. Documentation, workshops, training, and examples are accessible through Docker Desktop, the Docker website and blog, and the Docker Navigator newsletter. Additionally, the Docker documentation site offers comprehensive guides and learning paths, and Udemy courses co-produced with Docker help new users understand containerization and Docker usage.

The thriving Docker community also contributes a wealth of content and resources, including video tutorials, how-tos, and in-person talks.

Myth #8: Docker and container technology are only for developers

The idea that Docker is only for developers is a common misconception. Docker and containers are used across various fields beyond development. Docker Desktop’s ability to run containerized workloads on Windows, macOS, or Linux requires minimal technical knowledge from users. Its integration features — synchronized host filesystems, network proxy support, air-gapped containers, and resource controls — ensure administrators can enforce governance and security.

• Data science: Docker provides consistent environments, enabling data scientists to share models, datasets, and development setups seamlessly.
• Healthcare: Docker deploys scalable applications for managing patient data and running simulations, such as medical imaging software across different hospital systems.
• Education: Educators and students use Docker to create reproducible research environments, which facilitate collaboration and simplify coding project setups.

Docker’s versatility extends beyond development, providing consistent, scalable, and secure environments for various applications.

Myth #9: Docker Desktop is just a GUI

The myth that Docker Desktop is merely a graphical user interface (GUI) overlooks its extensive features designed to enhance developer experience, streamline container management, and accelerate productivity, such as:

Cross-platform support

Docker is Linux-based, but most developer workstations run Windows or macOS. Docker Desktop enables these platforms to run Docker tooling inside a fully managed VM integrated with the host system’s networking, filesystem, and resources.

Developer tools

Docker Desktop includes built-in Kubernetes, Docker Scout for supply chain management, Docker Build Cloud for faster builds, and Docker Debug for container debugging.

Security and governance

For administrators, Docker Desktop offers Registry Access Management and Image Access Management, Enhanced Container Isolation, single sign-on (SSO) for authorization, and Settings Management, making it an essential tool for enterprise deployment and management.

Myth #10: Docker containers are for microservices only

Although Docker containers are popular for microservices architectures, they can be used for any type of application. For example, monolithic applications can be containerized, allowing them and their dependencies to be isolated into a versioned image that can run across different environments. This approach enables gradual refactoring into microservices if desired.

Additionally, Docker is excellent for rapid prototyping, allowing quick deployment of minimum viable products (MVPs). Containerized prototypes are easier to manage and refactor compared to those deployed on VMs or bare metal.

Now you know

Now that you have the facts, it’s clear that adopting Docker can significantly enhance productivity, scalability, and security for a variety of use cases. Docker’s versatility, combined with extensive learning resources and robust security features, makes it an indispensable tool in modern software development and deployment. Adopting Docker and its true capabilities can significantly enhance productivity, scalability, and security for your use case.

For more detailed insights, refer to the 2024 Docker State of Application Development Report or dive into Docker Desktop now to start your Docker journey today. 

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Docker is known worldwide as a popular application containerization platform. But it also has a lesser-known and intriguing alter ego. It’s a popular go-to platform among web developers for its speed, flexibility, broad user base, and collaborative capabilities. 

Docker has been growing as a modern solution that brings innovation to web development using containerization. With containers, developers and web development projects can become more efficient, save time, and drive fresh creativity. Web developers use Docker for development because it ensures consistency across different environments, eliminating the “it works on my machine” problem. Docker also simplifies dependency management, enhances resource efficiency, supports scalable microservices architectures, and allows for rapid deployment and rollback, making it an indispensable tool for modern web development projects.

In this post, we dive into the benefits of using Docker in businesses from small to large, and review Docker’s broad capabilities, strengths, and features for bolstering web development and developer productivity. 

What is Docker?

Docker is secure, out-of-the-box containerization software offering developers and teams a robust, hybrid toolkit to develop, test, monitor, ship, deploy, and run enterprise and web applications. Containerization lets developers separate their applications from infrastructure so they can run them without worrying about what is installed on the host, giving development teams flexibility and collaborative advantages over virtual machines, while delivering better source code faster. 

The Docker suite enables developers to package and run their application code in lightweight, local, standardized containers that have everything needed to run the application — including an operating system and required services. Docker allows developers to run many containers simultaneously on a host, while also allowing the containers to be shared with others. By working within this collaborative workspace, productive and direct communications can thrive and development processes become easier, more accurate, and more secure. Many of the components in Docker are open source, including Docker Compose, BuildKit, the Docker command-line interface (Docker CLI), containerd, and more. 

As the #1 containerization software for developers and teams, Docker is well-suited for all flavors of development. Highlights include: 

• Docker Hub: The world’s largest repository of container images, which helps developers and open source contributors find, use, and share their Docker-inspired container images.
• Docker Compose: A tool for defining and running multi-container applications.
• Docker Engine: An open source containerization technology for building and containerizing applications.
• Docker Desktop: Includes the Docker Engine and other open source components; proprietary components; and features such as an intuitive GUI, synchronized file shares, access to cloud resources, debugging features, native host integration, governance, and security features that support Enhanced Container Isolation (ECI), air-gapped containers, and administrative settings management.
• Docker Build Cloud: A Docker service that lets developers build their container images on a cloud infrastructure that ensures fast builds anywhere for all team members. 

What is a container?

Containers are lightweight, standalone, executable packages of software that include everything needed to run an application: code, runtime, libraries, environment variables, and configuration files. Containers are isolated from each other and can be connected to networks or storage and can be used to create new images based on their current states. 

Docker containers are faster and more efficient for software creation than virtualization, which uses a resource-heavy software abstraction layer on top of computer hardware. Additionally, Docker containers require fewer physical hardware resources than virtual machines and communicate with their host systems through well-defined channels.

Why use Docker for web applications?

Docker is a popular choice for developers building enterprise applications for various reasons, including consistent environments, efficient resource usage, speed, container isolation, scalability, flexibility, and portability. And, Docker is popular for web development for these same reasons. 

Consistent environments

Using Docker containers, web developers can build web applications that provide consistent environments from their development all the way through to production. By including all the components needed to run an application within an isolated container, Docker addresses those issues by allowing developers to produce and package their containers and then run them through various development, testing, and production environments to ensure their quality, security, and performance. This approach helps developers prevent the common and frustrating “but it works on my machine” conundrum, assuring that the code will run and perform well anywhere, from development through deployment.

Efficiency in using resources

With its lightweight architecture, Docker uses system resources more efficiently than virtual machines, allowing developers to run more applications on the same hardware. Docker containers allow multiple containers to run on a single host and gain resource efficiency due to the isolation and allocation features that containers incorporate. Additionally, containers require less memory and disk space to perform their tasks, saving on hardware costs and making resource management easier. Docker also saves development time by allowing container images to be reused as needed. 

Speed

Docker’s design and components also give developers significant speed advantages in setting up and tearing down container environments, allowing needed processes to be completed in seconds due to its lightweight and flexible application architecture. This allows developers to rapidly iterate their containerized applications, increasing their productivity for writing, building, testing, monitoring, and deploying their creations.  

Isolation

Docker’s application isolation capabilities provide huge benefits for developers, allowing them to write code and build their containers and applications simultaneously, with changes made in one not affecting the others. For developers, these capabilities allow them to find and isolate any bad code before using it elsewhere, improving security and manageability.

Scalability, flexibility, and portability

Docker’s flexible platform design also gives developers broad capabilities to easily scale applications up or down based on demand, while also allowing them to be deployed across different servers. These features give developers the ability to manage different workloads and system resources as needed. And, its portability features mean that developers can create their applications once and then use them in any environment, further ensuring their reliability and proper operation through the development cycle to production.

How web developers use Docker

There is a wide range of Docker use cases for today’s web developers, including its flexibility as a local development environment that can be quickly set up to match desired production environments; as an important partner for microservices architectures, where each service can be developed, tested, and deployed independently; or as an integral component in continuous integration and continuous deployment (CI/CD) pipelines for automated testing and deployment.

Other important Docker use cases include the availability of a strong and knowledgeable user community to help drive developer experiences and skills around containerization; its importance and suitability for vital cross-platform production and testing; and deep resources and availability for container images that are usable for a wide range of application needs. 

Get started with Docker for web development (in 6 steps)

So, you want to get a Docker container up and running quickly? Let’s dive in using the Docker Desktop GUI. In this example, we will use the Docker version for Microsoft Windows, but there are also Docker versions for use on Mac and many flavors of Linux. 

Step 1: Install Docker Desktop

Start by downloading the installer from the docs or from the release notes.

Double-click Docker Desktop for Windows Installer.exe to run the installer. By default, Docker Desktop is installed at C:\Program Files\Docker\Docker.

When prompted, be sure to choose the WSL 2 option instead of the Hyper-V option on the configuration page, depending on your choice of backend. If your system only supports one of the two options, you will not be able to select which backend to use.

Follow the instructions on the installation wizard to authorize the installer and proceed with the installation. When the installation is successful, select Close to complete the installation process.

Step 2: Create a Dockerfile

A Dockerfile is a text-based file that contains a running script of instructions giving full details on how a developer wants to build their Docker container image. A Dockerfile, which uses no file extension, is built by creating a file named Dockerfile in the getting-started-app directory, which is also where the package.json file is found. 

A Dockerfile contains details about the container’s operating system, file locations, environment, dependencies, configuration, and more. Check out the useful Docker best practices documentation for creating quality Dockerfiles. 

Here is a basic Dockerfile example for setting up an Apache web server. 

Create a Dockerfile in your project:

FROM httpd:2.4
COPY ./public-html/ /usr/local/apache2/htdocs/

Next, run the commands to build and run the Docker image:

$ docker build -t my-apache2
$ docker run -dit --name my-running-app -p 8080:80 my-apache2

Visit http://localhost:8080 to see it working.

Step 3: Build your Docker image

The Dockerfile that was just created allows us to start building our first Docker container image. The docker build command initiated in the previous step started the new Docker image using the Dockerfile and related “context,” which is the set of files located in the specified PATH or URL. The build process can refer to any of the files in the context. Docker images begin with a base image that must be downloaded from a repository to start a new image project.

Step 4: Run your Docker container

To run a new container, start with the docker run command, which runs a command in a new container. The command pulls an image if needed and then starts the container. By default, when you create or run a container using docker create or docker run, the container does not expose any of its ports to the outside world. To make a port available to services outside of Docker you must use the --publish or -p flag commands. This creates a firewall rule in the host, mapping a container port to a port on the Docker host to the outside world. 

Step 5: Access your web application

How to access a web application that is running inside a Docker container.

To access a web application running inside a Docker container, you need to publish the container’s port to the host. This can be done using the docker run command with the --publish or -p flag. The format of the --publish command is [host_port]:[container_port].

Here is an example of how to run a container and publish its port using the Docker CLI:

$ docker run -d -p 8080:80 docker/welcome-to-docker

In this command, the first 8080 refers to the host port. This is the port on your local machine that will be used to access the application running inside the container. The second 80 refers to the container port. This is the port that the application inside the container listens on for incoming connections. Hence, the command binds to port 8080 of the host to port 80 on the container system.

After running the container with the published port, you can access the web application by opening a web browser and visiting http://localhost:8080.

You can also use Docker Compose to run the container and publish its port. Here is an example of a compose.yaml file that does this:

services:
 app:
   image: docker/welcome-to-docker
   ports:
     - 8080:80

After creating this file, you can start the application with the docker compose up command. Then, you can access the web application at http://localhost:8080.

Step 6: Make changes and update

Updating a Docker application in a container requires several steps. With the command-line interface use the docker stop command to stop the container, then the existing container can be removed by using the docker rm (remove) command. Next, a new updated container can be started by using a new docker run command with the updated container. The old container must be stopped before replacing it because the old container is already using the host’s port 3000. Only one process on the machine — including containers — can listen to a specific port at a time. Only after the old container is stopped can it be removed and replaced with a new one. 

Conclusion

In this blog post, we learned about how Docker brings valuable benefits to web developers to speed up and improve their operations and creativity, and we touched on how web developers can get started with the platform on Day One, including basic instructions on setting up Docker quickly to start using it for web development.

Docker delivers streamlined workflows for web development due to its lightweight architecture and broad collaboration, application design, scalability, and other benefits. Docker expands the capabilities of web application developers, giving them flexible tools for everything from building better code to testing, monitoring, and deploying reliable code more quickly. 

Subscribe to our newsletter to stay up-to-date about Docker and its latest uses and innovations. 

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