What are the 5 best al­tern­at­ives to Docker?

Con­tain­er­isa­tion with Docker is the standard today – but it’s not always the best option for every situation. Tools like Podman or BuildKit offer strong al­tern­at­ives, providing benefits in areas such as security, CI/CD and per­form­ance. In this article, we’ll explore the best pro­fes­sion­al Docker al­tern­at­ives, compare their key features, and help you determine which solution is best for your specific use case.

Comparing Docker al­tern­at­ives at a glance

Why consider Docker al­tern­at­ives?

While Docker is a powerful tool, it’s not always the best option. Changes to Docker’s licensing, such as the com­mer­cial­isa­tion of Docker Desktop, have affected many busi­nesses. At the same time, Docker’s reliance on root access and its use of a central daemon can increase the potential attack surface, raising security concerns.

What’s more, Kuber­netes, the leading container or­ches­tra­tion tool, has moved away from Docker as its default runtime. Instead, it now uses runtimes like con­tainerd or CRI-O. For many use cases –es­pe­cially in security-sensitive en­vir­on­ments or automated CI/CD processes – spe­cial­ised tools may offer better solutions.

Podman – Docker without a daemon

Podman is currently the most well-known and direct al­tern­at­ive to Docker. What makes it par­tic­u­larly in­ter­est­ing is that Podman operates without a central daemon, allowing you to start container processes directly and, if needed, without requiring root access. This sig­ni­fic­antly enhances security, es­pe­cially in pro­duc­tion en­vir­on­ments.

Another advantage is high com­pat­ib­il­ity: If you’re already familiar with Docker, you’ll have no trouble with Podman, as its command structure is nearly identical. It also in­teg­rates seam­lessly with systemd and Kuber­netes.

However, there is a downside: Graphical User In­ter­faces (GUIs) or GUI tools for Podman are not as advanced as those for Docker Desktop. Also, for more complex multi-container projects, switching from Docker Compose may require some modi­fic­a­tions.

Con­clu­sion: Podman is ideal for de­velopers and ad­min­is­trat­ors looking for a secure, command-line-based and Docker-com­pat­ible al­tern­at­ive – es­pe­cially in pro­duc­tion Linux en­vir­on­ments.

BuildKit – The modern Docker builder

BuildKit was developed by the Docker team to replace the classic ‘docker build’ command. It stands out due to its superior speed, in­tel­li­gent caching, and the ability to manage build secrets, which is a huge benefit in complex CI/CD pipelines.

Parallel builds are also supported, making BuildKit par­tic­u­larly efficient. It can be enabled within Docker or used stan­dalone. When combined with Docker or Podman, it dra­mat­ic­ally boosts image building per­form­ance. The downside, however, is that BuildKit does not replace Docker entirely. It’s focused solely on the build process. Anyone wishing to manage or deploy con­tain­ers will need an ad­di­tion­al tool.

Con­clu­sion: BuildKit is perfect for DevOps teams and de­velopers who pri­or­it­ise fast, secure builds – es­pe­cially in automated en­vir­on­ments.

Kaniko – Container builds without Docker

Kaniko is a tool from Google spe­cific­ally designed for building con­tain­ers in Kuber­netes en­vir­on­ments – without Docker or root access. It runs entirely within a pod and can build images directly in the cloud, such as in GitHub Actions or Google Cloud Build.

This makes Kaniko ideal for automated CI/CD processes, where no ad­di­tion­al runtime en­vir­on­ment should be installed. An important advantage when it comes to security is that Kaniko runs without root access, meaning it can be used safely in shared cluster en­vir­on­ments. However, Kaniko is not a universal tool. It is not suitable for local de­vel­op­ment or in­ter­act­ive work in the command line – common features such as shell access or flexible container man­age­ment are missing.

Con­clu­sion: Kaniko is perfect for teams working in cloud-native en­vir­on­ments who want to securely automate con­tain­er­ised build processes – es­pe­cially in Kuber­netes en­vir­on­ments.

LXC / LXD – System-level con­tain­er­isa­tion

LXC (Linux Con­tain­ers) is a low-level tech­no­logy for operating system vir­tu­al­isa­tion under Linux, which has been around for over a decade. It allows you to run and manage complete Linux systems in con­tain­ers – commonly referred to as system con­tain­ers.

LXD, developed by Canonical in 2015, provides a user-friendly man­age­ment layer over LXC. It adds features like its own CLI, a REST API, image man­age­ment and snapshots, making it es­pe­cially useful in pro­fes­sion­al in­fra­struc­tures.

LXC and LXD – Why they came back together

In 2023, Canonical returned LXD to the LXC community, and since then, both projects have been developed together under the Linux Con­tain­ers Project. The goal of this merger is to ensure more trans­par­ent community-driven main­ten­ance and a closer in­teg­ra­tion of both com­pon­ents. While LXC remains the technical found­a­tion, LXD continues to serve as a user-friendly front end.

The func­tion­al division remains:

• LXC serves as the low-level tech­no­logy
• LXD remains the com­fort­able man­age­ment front end

Technical clas­si­fic­a­tion

Compared to Docker, LXC and LXD are much closer to tra­di­tion­al virtual machines. They provide full system en­vir­on­ments with init systems, user man­age­ment, package man­age­ment and more – far beyond the typical ap­plic­a­tions con­tain­ers offered by Docker or Podman. However, by not using a hy­per­visor, they still manage to remain light­weight and per­form­ant.

Lim­it­a­tions

The downside is that LXC/LXD is not optimised for mi­croservices, cloud-native de­ploy­ments, or modern CI/CD processes. The man­age­ment can be more complex, and in­teg­ra­tion into container eco­sys­tems like Kuber­netes is minimal.

Con­clu­sion: LXC and LXD are excellent for admins, hosting providers or teams that want to isolate full Linux systems – acting as a light­weight VM al­tern­at­ive. The merger under the Linux Con­tain­ers Project promises a more stable, community-main­tained future for both tech­no­lo­gies.

runC – The container runtime for advanced users

runC is the reference im­ple­ment­a­tion of the OCI Spe­cific­a­tion (Open Container Ini­ti­at­ive) and is used behind the scenes by many tools – such as Docker, Podman, or con­tainerd. Anyone who wants to manage con­tain­ers at the lowest level will likely need to use runC.

Its biggest advantage is its light­weight nature, since runC provides only the basics required to start con­tain­ers, making it highly flexible. It is ideal for custom container solutions or security-focused en­vir­on­ments.

However, runC is aimed at advanced users. It lacks a con­veni­ent CLI for container man­age­ment or building and is typically used as part of custom tool­chains or for deep system in­teg­ra­tion.

Con­clu­sion: runC is perfect for spe­cial­ised ap­plic­a­tions, research, security or low-level container en­vir­on­ments – it is not intended for everyday de­vel­op­ment.

Kuber­netes – Not a Docker al­tern­at­ive, but a layer above

A common mis­con­cep­tion is that Kuber­netes does not replace Docker. Instead, it relies on container runtimes to run con­tain­ers. While Docker was once the default runtime, Kuber­netes has since adopted stand­ard­ised runtimes like con­tainerd or CRI-O since version 1.20.

These tools handle container man­age­ment, but do not have their own build or CLI func­tion­al­ity like Docker. Therefore, Kuber­netes itself is not a Docker al­tern­at­ive, but an or­ches­tra­tion tool – a control layer above the con­tain­ers.

In practice, this means that anyone working with Kuber­netes should un­der­stand that Docker no longer serves as the technical found­a­tion – although many images still exist in the Docker format.

Which Docker al­tern­at­ive is right for you?

The right Docker al­tern­at­ive largely depends on your specific needs:

• For maximum security, Podman is the best choice.
• For high-per­form­ance builds, BuildKit stands out, while Kaniko is preferred in cloud en­vir­on­ments.
• For isolating entire systems, LXC/LXD is the better option.
• For full control at the runtime level, runC is a lean solution for pro­fes­sion­als.

Ul­ti­mately, it’s worth looking beyond Docker – the world of con­tain­ers is more diverse than ever before.