Imagine you worked hard to create an application with various libraries and dependencies. The application runs smoothly and efficiently on your system. What if want to send the application to someone else’s system? The person would require a whole lot of setup of the application to run it. Even after the setup, a single change in the code and configuration might disrupt the whole application on either of the systems or in the worst case both systems.
That’s when Docker entered the scene. It helps you to efficiently deploy and run your application across various platforms and systems. You can just take a screenshot of your application combined with all the setup intact and send it over to other systems to run it similarly as it is available to you on your local machine. It provides an isolated version of the application to be shared among various systems and platforms.
What is Docker?
Docker is an open-source platform developers use to build, deploy, run, update, and manage applications in containers. It helps separate the application from your infrastructure to help enable fast and efficient development. It provides the functionality to package and run an application in an isolated environment called a container.
Containers are standardized and executable components that combine application code with the operating system’s libraries and dependencies needed to set up the application’s environment. It is a lightweight, standalone, and executable package of software. The containers are industry standard so they can be used anywhere. They share the machine’s OS system kernel leading to higher server efficiency and lower server costs. The applications are also safe in containers as Docker provides the strongest default isolation capabilities.
To learn more, refer to this article: Introduction to Docker
Why use Docker?
Developers use Docker for efficient and consistent application packaging and deployment across different environments. It simplifies containerization and isolates applications for reliable, and scalable deployments. The following features of Docker make it so popular and extensively used worldwide among developers:
- Low Resource Consumption – Containers use the host machine’s OS thus there is no need to install an operating system on each container, making each container smaller and lightweight. The container can run on the cloud, so the need for large servers is also eliminated.
- Scalability – Docker supports both horizontal and vertical scaling. With horizontal scaling, you can deploy and manage multiple containers to manage the work and with vertical scaling, you can resize the computing resource by expanding or limiting the CPU resource.
- Container Versioning – Docker can manage the versioning of container images and can roll back to the previous version and even get the details of a specific version. Deltas between a version and the new version can also be uploaded.
- Flexibility and Versatility – Docker allows diversity of programming and system requirements required for the application eliminating the issue of cross-platform compatibility and ensuring flexibility and versatility.
Need For a Docker Alternative
Despite being a revolutionary approach to handling applications, Docker has its drawbacks that open space for alternatives to arise. The need for a Docker alternative arises from a need for more lightweight, faster, and specialized containerization solutions that better suit specific use cases.
- Security – All the containers use the host computer’s operating system and do not have one of their own. This created a security hole leading to the crashing of all the containers of the host computer attacked. This issue is not present in virtual machines as each VM has its own operating system.
- GUI(Graphical User Interface) – Docker is only present in the command line interface(CLI) and not available in a graphical user interface(GUI) which makes it only useful with prior knowledge of CLI.
- Learning Curve – The learning curve of Docker is very steep and may take a long time to get to know everything about the service.
Alternatives for Docker
Docker is a software that is used to fasten the development process by packing software into standarised units called docker. But there are places when Docker also gets slowed down or not perform up to the expectations, so developers have build its alternative that are relevant depending on the project requirement and these are also widely used in the industry that you should definitely know about.
- Podman
- Linux Container Daemon
- Kubernetes
- Vagrant
- Containerd
- BuildKit
- Buildah
- ZeroVM
- Microsoft Azure Container Registry
- RunC
1. Podman
Podman is an open-source visualization tool developed by RedHat. It leverages the libpod library for container lifecycle management tools. It is a daemonless container engine OCI management on Linux. It is basically made for Linux but can be run on Windows and Mac using Podman-managed virtual machines.
Features
- The container engine runs on a daemonless architecture leading to no need for root privileges for container execution.
- Podman can be integrated with third-party services to enhance its functionality.
- Executing commands and operations like pulling and tagging, that update and modify OCI pictures.
- Podman is compatible with other OCI-compliant container formats.
Podman vs Docker
- Docker uses a daemon process to establish a connection between server and client while Podman processes a single process with child processes.
- Root privileges are not required to create a container in Podman while that is not the case for Docker.
2. Linux Container Daemon(LXD)
Linux Container Daemon(LXD) is a Linuc container and virtual machine manager developed by Canonical. Linux Container Daemon provides flexibility by providing a single process for multiple containers. It uses REST API to connect to the Linux Container Library(LXC). It is an add-on to LXC to provide more features and functionalities.
Features
- It has a powerful command line interface(CLI) called ‘lxc’ is used to deploy and manage Linux OS container instances.
- Linux Container Daemon provides storage and network management capabilities such as storage pooling.
- Linux Container Daemon supports snapshots and live migration features.
- Linux Container Daemon provides a data retrieval facility after data processing.
Linux Container Daemon vs Docker
- Linux Container Daemon is faster than Docker for executing applications while using multiple processors.
- Linux Container Daemon is for stateful containers, used to containerize operating systems while Docker only supports stateless containers, used to containerize services.
3. Kubernetes(K8)
Kubernetes also known as ‘K8’ is a container orchestration tool developed by Google. It is used for the automation of app deployment, scaling and management of containerized applications. Docker and Kubernetes can be combined together for better management of containers.
Features
- Kubernetes provides an automatic scaling feature that helps expand or limit resources based on usage.
- It is a declarative model, i.e. the developer describes a state and K8 works in the background to manage the state and handle failures.
- It supports various internal and external load-balancing schemes.
- Application self-healing is one of the main features that is achieved by auto-placement, auto-restart, auto-replication and auto-scaling.
Kubernetes vs Docker
- Kubernetes is a better choice than Docker when orchestrating large distributed applications with many microservices like databases, secrets and external dependencies.
- The automatic Scaling and self-heling properties of Kubernetes give it an edge over Docker.
4. Vagrant
Vagrant is a tool for building and managing Virtual machine environments on a single workflow. It was developed by Hashicorp and is used to replicate multiple virtual environments. It can be run efficiently on all virtualization environments providing the highest level of isolation to users.
Features
- Vagrant provides interoperability.
- It can be easily integrated with continuous integration (CI) tools like Jenkins allowing you to automate tests and build pipelines.
- Vagrant promotes a multi-machine environment by using Virtual Machines that can be used on any operating system.
- It supports versioning and sharing of base images called ‘boxes’ which can be shared using Vagrant Cloud.
Vagrant vs Docker
- Docker relies on the operating system of the host computer while Vagrant creates Virtual Machines that have their own operating systems. Docker runs on Linux systems while VMs can run on any operating system thus Vagrant is not operating system restrictive.
- Vagrant provides better security than Docker as they create VMs that have their own operating systems and are not shared.
5. Containerd
Containerd is a runtime tool that manages image transfer and storage and manages OCI containers. It can be integrated with Docker but can also be used without Docker integration. It can be used as a standalone component by using runc.
Features
- Namespaces enable separation between groups of containers on the same host, thus two containers with the same name and different namespaces can be run on a single machine.
- Snapshot capabilities can be extended by using additional plugins.
- Easily integrable with tools like runc, Kubernetes engine, Amazon Kubernetes Service and Azure Kubernetes Service.
- Cloning of containers for transfer and restoring using checkpoints is also available.
Containerd vs Docker
- Containerd can create containers without extra support but that is not the case with Docker.
- Containerd can function without Docker and can still start containerization if Docker is absent but vice versa is not true.
6. BuildKit
BuildKit is an image builder by Moby for building and packaging software using containers. It helps make Docker images more efficient, faster and secure. It works on multiple export environments like OCI or Docker.
Features
- BuildKit provides features like efficient caching and running parallel build operations.
- It provides execution rights without root privileges.
- Automatic Garbage Collection helps manage the container efficiently.
- It supports extendable frontend formats and multiple output formats.
BuildKit vs Docker
- BuildKit enabled with Docker provides better performance by parallel build processing while standard Docker build performs build on Dockerfiles serially.
- BuildKit handles complex scenarios like detecting and skipping building unused build stages which are not addressed by standard Docker build.
7. Buildah
Buildah is an open-source tool developed by RedHat. It allows users to create OCI-compliant images without installing a daemon or a container runtime. It provides a simple command line interface making it easy to learn and use. Buildah can be used as a standalone application or with tools like Podman.
Features
- Buildah allows you to create containers as a non-root user by using its daemon-less nature.
- It can be easily incorporated into scripts and can be used to build pipelines.
- Buildah does not require a running container daemon to build images.
- Buildah containers are compatible with Docker and Kubernetes as well.
Buildah vs Docker
- Docker requires a running container while Buildah does not.
- Buildah does not require Dockerfiles to function while Docker does.
8. ZeroVM
ZeroVM is an open-source virtualization and sandboxing technology. It helps users by creating a secure and isolated execution environment that provides a single thread and application. It uses the Google Native Cloud platform to virtualize a single process.
Features
- ZeroVM makes it easy to create large clusters of instances leading to hyperscalability.
- Execution inside ZeroVM is deterministic.
- It can be embedded into existing storage systems.
- Security is derived from Chromium Native Client(NaCI) based on software fault isolation.
ZeroVM vs Docker
- Security in ZeroVM is higher than in Docker as data is embedded in an isolated environment.
- Deployment speed for ZeroVM is lower than Docker.
9. Microsoft Azure Container Registry
Microsoft Azure Container Registry allows access to Docker’s private registry. It helps store and manage Docker images using Docker CLI tools. It can be integrated with Docker Swarm and Kubernetes to provide more scalable and efficient implementation.
Features
- It provides integrated security with Azure active directory authentication and other features.
- Provide automated container building and patching.
- It has features like Twist local compatibility, runtime protection and scanning for container vulnerabilities;
Microsoft Azure Container Registry vs Docker
- Docker only stores container images while Microsoft Azure Container Registry stores Helm charts images built to OCI image specification format.
10. RunC
RunC is a Github-hosted CLI tool built with Go for spawning and running containers on a Linux system. Earlier RunC was not a standalone tool, i.e. it wasn’t advised to be used directly as an end user but nowadays you can use it as a standalone tool or as a part of Docker.
Features
- Provides all low-level functionality for containers like namespace and control groups.
- Lightweight, universal and portable container runtime.
- Does not require Windows support.
RunC vs Docker
- RunC is the underlying container runtime for Docker.
Conclusion
Docker has proved to be one of the revolutions in application management and container orchestration. It has helped to bridge the cross-platform compatibility gaps efficiently. Yet some drawbacks also exist with this cutting-edge technology due to which alternatives and better versions of container management tools arose. In this article, we discussed the drawbacks of Docker along with its alternatives that can be used based on developers’ use cases. But it is important to note that, you should choose your tools wisely according to your project demenad and requirements.
FAQs on Docker Alternatives
1. What was used before Docker?
Before the rise of Docker, developers used virtualization applications to build applications. These virtual applications can be Virtual Machines or other applications providing an environment to run the application.
2. Will Docker be used in the Future?
Docker container’s portability, usability, efficiency and scalability make it a go-to choice and with the evolution of development and deployment, Docker will play a major role in the future.
3. What are the alternatives compatible with Docker?
Docker compatible Docker alternatives that can be used along with Docker for better functionality and efficiency are
- Podman
- Buildah
- BuildKit
- Kubernetes
