DEV Community

Foss Guru
Foss Guru

Posted on

What is Docker? What are the best Docker Alternatives?

Docker has managed to win many hearts and I am no exception. But, after using it for a while and exploring most of its capabilities, I looked for an alternative. For me, LXC works well when I don’t want to use Docker. It’s a low-level container management tool and is a great way to have an isolated and dedicated application ecosystem. It works on the Unix model and each container will behave as an individual. When I need to run more than one container at a time, it’s a real savior for me as Docker allows only one container in a single process.

Docker is the world's most widely known and most widely used container platform. But there are other alternatives with their approaches and uses. So if you're looking to purchase container software, then here are a few alternatives-

Artifactory Docker Registry-

This is a secure private registry that manages Docker images, providing access to remote Docker container registries with integration to build ecosystems. It allows you to set up unlimited Docker registries, using local, remote or virtual Docker repositories. It manages Docker images, which have been created internally and downloaded from Docker resources.

rkt from CoreOS

It is the next name after Docker in container technology. Being most widely used, it has a massive community of developers. rkt can handle many different container formats, including Docker images. This makes it a perfect replacement for Docker. rkt is a more secure container solution that addresses many of the shortcomings of Docker's container.

A significant drawback of Docker is that it runs a daemon. This daemon runs on top of the system process and performs most of the core functions of the docker framework. When we attempt to begin a Docker process, a client process of Docker asks the Docker daemon to start executing the container. The system process was not designed to be run in this way. Often, the process fails to start and eventually results in the creation of multiple container instances.

rkt framework has a simpler architecture where it directly runs on top of the system and serves its applications. This simplified architecture significantly reduces system overhead.

Because rkt is an application container runtime, it, unlike Docker, may execute several apps within a container. Thus, we will have active monitoring of the container and resume the process in a new container if several methods share the same container.

Another significant advantage of rkt over Docker is the security of the container images. In Docker, a public image repository is available for download and customization. This opens the door for the potential of authentic server images being swapped by malicious ones. Signature verifications are performed in RKT, which means that as soon as the server image is downloaded, it is verified to see whether it has been tampered with.

To replicate the docker behaviour you need to make sure you run podman with sudo, otherwise, it will run the containers as the currently logged-in user. It is still using yaml syntax since it is ansible, however, it allows much more control over the deployment and as a bonus, allows you to control deployment on multiple hosts, centralizing configuration.

If you want the DNS auto-discovery to work (as with docker-compose) you'll need to make sure you install the DNS name CNI plugin.

Also, just because podman supports rootless containers does not mean you need to use it in that way. Its use cases are limitless. Essentially, if Docker could handle it, you can count on Podman just the same.

Also, for long-running services on system distros, podman can generate system unit files to control the container lifecycle. This is much cleaner than having the monolithic Docker Daemon always running in the background.


Virtual box is a great alternative to docker. It runs in nearly any operating system on a single machine and to freely switches between os instances running simultaneously. It also provides great speed and portability

However, the only downside is that a virtual box is not a container. VM's are built for applications that are usually more static and don't change very often. Whereas containers are more flexible and make it possible to easily and frequently update your container

The first docker alternative is Podman. Podma is an open-source, alternative virtualization platform by RedHat. Like Docker, you can use the Podman container engine to develop, manage, and run OCI containers on Linux machines. However, Podman Container Engine runs on a daemoless architecture that does not require root privileges.

With Podman, containers are run in the background without root privileges because it integrates directly with systemD (system daemon), which allows it to run in the background. Hence, the system takes over the Docker daemon functionality in Podman.

Secondly, VirtualBox is another alternative. It may not be as portable as Docker or other Docker alternatives. Still, it offers users the benefits of running any OS type on a single machine, running Graphics-based applications smoothly, easy sharing of files and folders, cross-platform support, and a more secure virtual environment without requiring hardware virtualization.

Like Docker, VirtualBox runs on open-source code under the GNU General Public License version 2 (GPL v2).

LXC (Linux Containers)

LXC (Linux Containers) is an OS-level virtualization technology that allows the creation and operation of multiple separate Linux (VE) sites in a single control unit. These splits or containers can be used for specific sandbox applications, or to mimic a completely new manager. LXC is a collection of low-quality container management tools that are part of the LinuxContainers open source project. The technology is a precursor to Docker. The goal of the LXCLXC is to provide a unique application environment that is almost identical to that of a fully-fledged (VM) machine but without the theme of using its kernel. LXC also follows the Unix process model, Simply put, instead of being managed by a single, intermediate system, each container behaves as if it were run by a different system privately.


The Podman is an open-source container engine, which performs the same role as the Docker engine. It distinguishes itself because its separation features and user rights make Podman naturally secure.

Equally, its CLI commands are almost identical to those supported by the Docker Command Line Interface.

Although Docker and Podman CLI's instructions are similar, knowing how to tell the difference between the two will help you when working with them. Unlike Docker, Podman works without a central daemon. This can improve the durability of any given vessel by eliminating the possibility of losing control of your containers. In contrast, Podman containers are independent, completely isolated areas, which cannot be controlled independently. While Docker standardly allows root permission to the container user, non-root access is by default on Podman.

I’m humbled to be helpful and it will be my pleasure to share with you more insights should you need them.

Top comments (1)

bastothemax profile image

Have you taken a look at Sysbox? It's a container runtime for docker that has systemd support. With this, you can run multiple processes in a single container.