Top 5 Docker Alternatives for Software Developers in 2024

Imagine you’ve worked hard to create an application with various libraries and dependencies. It runs smoothly and efficiently on your system. But what happens when you need to send the application to someone else’s system? That person would need to go through a lot of setup to get it running. Even after setup, a single change in the code and configuration could break the entire application on either system, or worse, on both systems.

This is where Docker comes into play. It helps you deploy and run applications efficiently across various platforms and systems. You simply take a snapshot of your application along with all its settings and send it to another system, where it runs in a similar way as on your local machine. It provides an isolated version of the application that can be shared across different systems and platforms.

What is Docker?

Docker is an open-source platform used by developers to build, deploy, run, update, and manage applications in containers. It helps decouple applications from the underlying infrastructure, enabling rapid and efficient development. It offers the ability to package and run applications in isolated environments called containers.

Containers are standardized executable components that combine application code with the operating system libraries and dependencies required to set up the application environment. They are lightweight, standalone, and executable software packages. These containers are industry standards, so they can be used anywhere. They share the machine's operating system kernel, which increases server efficiency and reduces server costs. Applications in containers are also secure, as Docker provides the strongest default isolation capabilities.

Why use Docker?

Developers use Docker to efficiently and consistently package and deploy applications across different environments. It simplifies containerization and isolation of applications for reliable and scalable deployment. The following features make Docker so popular and widely used among developers worldwide:

• Low Resource Consumption: Containers use the host's operating system, so there is no need to install an operating system for each container, making each container smaller and lighter. Containers can run on the cloud, eliminating the need for large servers.
• Scalability: Docker supports both horizontal and vertical scaling. With horizontal scaling, you can deploy and manage multiple containers to handle workloads, and with vertical scaling, you can adjust computing resources by expanding or limiting CPU resources.
• Container Version Control: Docker can manage version control for container images and can roll back to previous versions, even retrieving detailed information for specific versions. It also allows uploading the delta between versions and new versions.
• Flexibility and Versatility: Docker allows for the diversity of programming and system requirements needed by applications, eliminating cross-platform compatibility issues, ensuring flexibility and versatility.

Need for Docker Alternatives

Despite being a revolutionary way to handle applications, Docker has its downsides, paving the way for alternatives. The need for Docker alternatives arises from the demand for lighter, faster, and more specialized containerization solutions that are better suited for specific use cases.

• Security: All containers use the host's operating system and do not have their own operating system. This creates a security vulnerability, causing all containers of a compromised host to crash. This issue does not exist in virtual machines, as each VM has its own operating system.
• GUI (Graphical User Interface): Docker exists only in the Command Line Interface (CLI) and is not available in a Graphical User Interface (GUI), making it useful only if you have prior knowledge of the CLI.
• Learning Curve: Docker has a steep learning curve and may take a long time to learn everything about the service.

Docker Alternatives

Docker is software used to accelerate the development process by packaging software into standardized units called containers. However, in some scenarios, Docker may slow down or not perform as expected, leading developers to build relevant alternatives based on project requirements. These alternatives are also widely used in the industry and are worth knowing about.

1. Podman
2. Linux Container Daemon (LXD)
3. Kubernetes (K8s)
4. Vagrant
5. Containerd

Podman

Podman is an open-source visualization tool developed by RedHat. It leverages the libpod library as a container lifecycle management tool. It is a daemonless container engine OCI management on Linux. It is primarily made for Linux but can run on Windows and Mac using virtual machines managed by Podman.

Features

• The container engine runs on a daemonless architecture, allowing containers to be executed without root privileges.
• Podman can integrate with third-party services to enhance its functionality.
• Commands and operations such as pull and tag can be executed to update and modify OCI images.
• Podman is compatible with other OCI-compliant container formats.

Podman vs Docker

• Docker uses a daemon to establish connections between the server and client, while Podman uses subprocesses to handle individual processes.
• Creating containers in Podman does not require root privileges, which is not the case with Docker.

Linux Container Daemon (LXD)

Linux Container Daemon (LXD) is a container and virtual machine manager developed by Canonical. It provides flexibility by offering a single process for multiple containers. It connects to the Linux container library (LXC) using a REST API. It is an add-on to LXC, providing more features and functionalities.

Features

• It has a powerful command-line interface (CLI) called "lxc" for deploying and managing Linux OS container instances.
• Offers storage and network management features like storage pools.
• Provides data retrieval tools after data processing.

LXD vs Docker

• LXD executes applications faster than Docker when using multiple processors.
• LXD is suitable for stateful containers used for containerizing operating systems, while Docker supports stateless containers used for containerizing services.

Kubernetes (K8s)

Kubernetes, also known as "K8s," is a container orchestration tool developed by Google. It is used to automate the deployment, scaling, and management of containerized applications. Docker and Kubernetes can be combined for better container management.

Features

• Kubernetes offers auto-scaling, helping scale or limit resources based on usage.
• It is a declarative model where developers describe a state, and K8s works in the background to manage the state and handle failures.
• Supports various internal and external load balancing schemes.
• One of its main features is self-healing applications through automatic placement, auto-restart, auto-replication, and auto-scaling.

Kubernetes vs Docker

• Kubernetes is a better choice than Docker for orchestrating large distributed applications with numerous microservices (such as databases, secrets, and external dependencies).
• Kubernetes' auto-scaling and self-healing properties give it an edge over Docker.

Vagrant

Vagrant is a tool for building and managing virtual machine environments in a single workflow. Developed by Hashicorp, it is used to replicate multiple virtual environments. It can efficiently run in all virtualized environments, providing the highest level of isolation to users.

Features

• Vagrant offers interoperability.
• It can easily integrate with continuous integration (CI) tools like Jenkins, enabling test automation and pipeline building.
• Facilitates multi-machine environments using virtual machines that can be used on any operating system.
• Supports version control and sharing of base images called "boxes," which can be shared using Vagrant Cloud.

Vagrant vs Docker

• Docker relies on the host's operating system, while Vagrant creates virtual machines with their own operating systems. Docker runs on Linux systems, while VMs can run on any operating system, making Vagrant not restricted by OS.
• Vagrant offers better security than Docker as the VMs they create have their own operating systems and do not share them.

Containerd

Containerd is a runtime tool used for managing image transfers and storage as well as managing OCI containers. It can be integrated with Docker but can also be used without Docker integration. By using runc, it can function as a standalone component.

Features

• Namespaces: Allow separation between groups of containers on the same host, enabling two containers with the same name but different namespaces to run on one machine.
• Snapshot Extensions: Can be extended with other plugins to enhance snapshot functionality.
• Integration: Easily integrates with tools like runc, Kubernetes Engine, Amazon Kubernetes Service, and Azure Kubernetes Service.
• Container Cloning: Can clone containers for transfer and recovery using checkpoints.

Containerd vs Docker

• Standalone Container Creation: Containerd can create containers without additional support, whereas Docker cannot.
• Independence from Docker: Containerd can run without Docker, allowing containerized operations to start even in Docker's absence, and vice versa.