10 Docker Myths Debunked

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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