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Docker Open Source: Engine Architecture, Tools

07th Sep, 2023
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    Docker Open Source: Engine Architecture, Tools

    Docker is a popular open source project for software containerization. It's been around for a few years now and has gained a lot of traction in the development community. The basic idea behind Docker is to package an application and all its dependencies into a single container. This makes it easy to deploy and run the application on any machine, regardless of the operating system or environment. 

    Docker also uses some clever tricks to improve performance and make development easier. It uses the resource isolation features of the Linux kernel such as cgroups and namespaces to allow independent "containers" to run within a single Linux instance, avoiding the overhead of starting virtual machines. 

    Docker Open Source also provides a set of powerful tools for managing containers. Moreover, you can always look for DCA certification as it can guide you with using the budibase docker, airbyte docker image & more to replicate data from a MySQL database into a PostgreSQL database. To make things clearer before your advanced certification, we'll take a closer look at the architecture of Docker and explore some of the key tools it provides. 

    Docker Open Source - An Overview 

    Docker provides an open source platform for developers & sysadmins to create, ship, & execute distributed applications. Comprising Docker Open Source Engine, an application container engine, and Docker Hub, Docker enables applications to be easily assembled from the components and removes the friction between QA, development, and production environments. Thus, it can ship quicker and run the same application, unchanged, on data centers and any other cloud. 

    Architecture of Docker Open Source Engine

    Docker open source architecture consists of three major components:

    1. The Docker Daemon

    The docker daemon is the heart of the docker engine open source. It is a long-running process that manages containers and handles container requests from the docker client. The docker daemon listens for API docker requests and responds to them. It also provides an interface to other parts of the docker system, such as storage drivers, networking plugins, and image scanners. The docker daemon is written in Go and is compiled into a single binary called dockerd. dockerd can be configured using a json file or passed command line arguments.

    2. The Docker Client

    The Docker Client is the main way that end users interact with Docker. It is a command-line interface (CLI) that can be used to create and manage Docker containers. The Docker Client communicates with the Docker Daemon. It also has a graphical user interface (GUI) that can be used to manage Docker containers. The GUI is provided by third-party tools such as Lazydocker and Portainer. 

    3. The Docker Registries

    They are used to store and distribute images. There are two types of Docker Registries: public and private. Public registries are free to use and anyone can access them. Private registries require a subscription and they are only accessible to authorized users.

    Docker Drivers

    Docker provides different storage drivers for containers namely:


    The Device Mapper storage driver is the original storage driver for Docker. It was created to address the limitations of the existing storage drivers, and it quickly became the default storage driver for new installations of Docker. In particular, it is difficult to use with devices that do not support thin provisioning. Moreover, Devicemapper is used by some container orchestration tools, such as Kubernetes. To get a detailed overview of such orchestration tools, you can look out for the docker and Kubernetes training sessions online. 


    Fuse-overlayfs is a docker repository open source driver that provides a number of additional features and capabilities not found in the standard docker engine. These include support for multiple storage backends, snapshotting, and advanced container management. Fuse-overlayfs is an essential tool for anyone looking to extend the functionality of their docker platform. 


    Aufs is the most popular type and is used by default in most Linux distributions. It uses a copy-on-write strategy to minimize disk writes and avoid corruption. Moreover, Aufs supports multiple open source container registry, including Docker Hub and Quay. Aufs is also included in the stable release of the Linux kernel. 

    Btrfs and Zfs

    Btrfs and Zfs are two of the most popular storage drivers used with containers. Btrfs is a copy-on-write filesystem that is widely used in Linux for its excellent performance and scalability features. Zfs is a next-generation file system designed for enterprise storage systems. Both drivers are available under docker open source license.


    By default, Docker open source uses the Vfs driver, which offers good performance and isolation but is not as flexible as other drivers. The Vfs driver is best suited for development and testing environments. Moreover, Vfs is a lightweight driver that provides simple storage for container images.


    Overlay2 is the preferred docker storage driver. It supports multiple lower-layer storage options, has good performance, and supports features like snapshotting and cloning. While it has been the default storage driver since Docker 18.06, some users Still prefer to use other drivers for specific purposes. In addition, Overlay2 supports features like snapshotting and cloning, which can be useful for taking checkpoints or creating new images.

    Open Source Tools for Docker Security

    Here is the basic overview of the Docker open source tools but to get a professional DevOps online course would make you a pro in the field of app development.

    Docker Bench for Security 

    Docker Bench for Security is an open source tool that can be used to assess the security of Docker containers. The tool performs a number of checks against a running container, including checks for exposed daemon sockets, insecure permissions on Docker volumes, and more. Additionally, Docker Bench for Security can be used to check for compliance with best practices outlined in the CIS Benchmark for Docker. 


    Clair is a Docker open source project for static vulnerability analysis of containers. Clair scans containers and looks for vulnerabilities in the packages that they use. If a vulnerability is found, Clair will report it along with information about the package and the version that are affected. This information can be used to create security policies that restrict which containers can run on a host. 


    Notary is an open source tool that can be used to verify the integrity of Docker images. It does this by using cryptographic signatures to ensure that images have not been tampered with. Notary can be used to sign images locally, or it can be used to verify the signatures of images that have been downloaded from an open source docker registry. In addition, Notary can be integrated with Docker Hub, allowing users to easily verify the authenticity of images before pulling them down


    Dagda is designed to provide a detailed overview of the contents of Docker images, including vulnerabilities and exposed ports. It currently supports Dockerfile and OCI image formats, and can be run against local or remote images. It can also be used to scan for malware and malicious code. Also, Dagda can be used to monitor containers for suspicious activity, and generate reports that can be used to improve container security. 


    Anchore is a Docker open source tool that can be used to monitor and analyze Docker images for security vulnerabilities. It operates by scanning the contents of a Docker image and comparing it against a database of known vulnerabilities. If any vulnerabilities are found, Anchore will report them so that they can be addressed. In addition to vulnerability scanning, Anchore also provides a number of other features such as image signing and policy enforcement. 


    Trivy is another open source tool that helps to secure Docker containers. Like Anchore, it performs static code analysis on Docker images to find vulnerabilities. However, Trivy goes one step further by also scanning for malware. In addition, Trivy can be run inside a container, making it ideal for use in CI/CD pipelines. Overall, Trivy is a comprehensive solution for securing Docker containers.

    OpenSCAP Workbench

    OpenSCAP Workbench is a graphical interface for analyzing and remediating security vulnerabilities in Docker containers. It can be used to scan images and running containers for common vulnerabilities. OpenSCAP Workbench can also be used to create and manage security policies, which can be applied to images and containers. These policies can help to prevent vulnerabilities from being exploited, and can also help to mitigate the effects of attacks. 

    Sysdig Falco

    Falco is a container security monitor that uses sysdig's kernel-level visibility to detect suspicious activity within containers. Falco can be used to detect things like unapproved container images being deployed, processes making unusual network connections, or privileged users accessing sensitive files. By providing granular visibility into container activity, Falco can help to prevent malicious activity from going undetected. 


    Grafaes is an open source tool that provides a web-based interface for managing Docker images and containers, and includes features such as image signing and verification, container scanning, and more. In addition, Grafaes integrates with a number of other open source tools, making it easy to add security controls to your existing workflows. It also includes features for auditing container activity, so that you can quickly identify any suspicious behavior. 


    Cilium is an open source tool that offers network security, visibility, and load balancing for containers and microservices. Based on the BPF kernel feature, Cilium works by attaching a BPF program to each container in order to intercept network traffic. This allows Cilium to provide granular security policies and visibility into network traffic. Cilium also includes a built-in load balancer, which can be used to distribute traffic across a cluster of containers. 

    Closing Notes

    Docker Open Source is a game changer in the world of application development and deployment. The architecture of the Docker open source engine is fascinating, and the drivers make it possible for developers to create sophisticated applications that can be deployed anywhere. Docker security is enhanced by the use of open source tools, which makes it possible for businesses to deploy containers securely with confidence. 

    Thus, we explored how the architecture works and delve into some of the more popular tools that are available to help you get started with Docker. While there is a lot of information to take in, we hope that this overview has given you a good foundation on which to start building your own dockerized applications. 

    Frequently Asked Questions (FAQs)

    1Is Docker open source and free?

    Docker is open source, but it is not free. You can download and use the community edition of docker for free, but you will need to pay for a subscription to use the enterprise edition.

    2Is Docker freeware?

    No, docker is not freeware. As mentioned above, you can use the community edition for free, but you will need to pay for a subscription to use the enterprise edition.

    3Is it possible to use Docker without Docker desktop?

    Yes, it is possible to install docker without installing docker desktop. However, docker desktop provides an easy way to get started with docker and includes many useful tools.

    4Is Docker free without a desktop?

    Yes, docker is free without docker desktop. However, docker desktop provides an easy way to get started with docker and includes many useful tools.


    Abhresh Sugandhi


    Abhresh is specialized as a corporate trainer, He has a decade of experience in technical training blended with virtual webinars and instructor-led session created courses, tutorials, and articles for organizations. He is also the founder of Nikasio.com, which offers multiple services in technical training, project consulting, content development, etc.

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