Docker came onto the container scene to simplify container deployments. But today, there are growing numbers of alternatives, each emerging with its own niche advantages. So, whether teams seek flexible architecture, broader tool integration, or more granular access controls, it’s worth knowing the world beyond this popular containerization platform. 

What is Docker? 

First, Docker is a containerization platform that uses Linux kernel features like groups (for resource allocation) and namespaces (for isolation) to run containers, lightweight packages containing software and all its dependencies. 

It emerged in the 2010s not as the first containerization platform but as a standout with features that made containerization more developer-friendly. Docker built on existing technology like Linux containers but introduced a user-friendly command-line interface (CLI), Docker hub for image sharing, and portable images.

Its accessibility drove the widespread adoption of containerization and, ultimately, container orchestration platforms like Kubernetes and Docker Swarm to help manage and deploy containers at scale.

However, Docker couldn’t address challenges like streamlined Kubernetes integrations, security for large-scale production environments, and predictable licensing models. Core drawbacks today include: 

• Licensing: Docker’s licensing changes for Docker Desktop may frustrate enterprises.
• Resource overhead: Docker’s architecture can introduce unnecessary overhead in certain scenarios.
• Kubernetes compatibility: Some alternatives are purpose-built for Kubernetes and simplify integration.
• Security and isolation: Alternatives may offer stronger isolation mechanisms and minimize attack surfaces.

So, what are the alternatives?

Containerization without Docker

Foregoing containerization altogether is an alternative to Docker, but it can be a non-starter for teams committed to the benefits of containerization, from resource efficiency to portability. 

According to Gartner, 85% of organizations will be using containers in production by 2025, up from 35% in 2019.

While containers are popular, they’re not required.

There are alternatives, such as virtual machines (VMs), but teams will need to trade away the resource efficiency of containers for an architecture that includes a complete operating system, including its own kernel, system libraries, and utilities. VMs also require a hypervisor to create and manage them, adding additional overhead.

There are also bare metal deployments, unikernels, Function-as-a-Service (FaaS) computing like AWS Lambda, process isolation tools (like namespaces and chroot, using manual setup), and Platform-as-a-Service (PaaS), which abstracts infrastructure.

Containerization can’t align with all needs. Solutions like VMs provide stronger isolation for legacy applications, while serverless computing simplifies event-driven workloads. Specialized cases like high-performance computing and real-time applications can benefit from bare metal setups, while IoT sensors and edge computing can be deployed best on unikernel. Each approach has benefits and drawbacks, and the choice depends on environmental factors and requirements.

11 Container Alternatives to Docker

For teams committed to containerization, but seeking a Docker alternative, there’s a rich landscape of options. As organizations have sought to improve on Docker’s weaknesses, add new features, or cater to specialized use cases, specialized containerization platforms have emerged to cater to a range of needs. Here are 11 viable contenders:

1. Podman

Podman (short for “Pod Manager”) is a container engine developed by open-source software giant Red Hat. Unlike Docker, it’s daemonless and rootless, so it offers a flexible architecture that can run securely in different environments.

Here’s how its features might appeal to teams seeking Docker alternatives:

• Daemonless architecture: Unlike Docker, Podman doesn’t require a central daemon, which reduces single points of failure. 
• Rootless containers: Podman improves security by allowing containers to run without root privileges. 
• Docker-compatible CLI: Podman supports a CLI compatible with Docker, easing migration.

Podman is best for organizations prioritizing security and flexibility, especially in Red Hat ecosystems.

2. CRI-O

CRI-O is a lightweight, Kubernetes-native container runtime developed by the Kubernetes community. Designed to integrate seamlessly with Kubernetes, it offers a streamlined and efficient way to manage containers. 

These features make it an attractive Docker alternative:

• Kubernetes-native design: CRI-O is purpose-built to implement the Kubernetes Container Runtime Interface (CRI), avoiding unnecessary features unrelated to Kubernetes.
• Lightweight and efficient: CRI-O focuses solely on running containers, which minimizes resource usage.
• Enhanced security: CRI-O includes built-in support for SELinux and seccomp for better security. Further, it leverages Kubernetes role-based access control (RBAC) and namespace isolation for fine-grained container management.

CRI-O is a good alternative to Docker for Kubernetes users who want a purpose-built runtime optimized for Kubernetes environments.

3. containerd

containerd is a minimal container runtime originally developed by Docker and now maintained by the Cloud Native Computing Foundation (CNCF). It provides the essential functionality for running and managing containers without extra layers. 

Here’s why it’s worth considering:

• Simplicity: containerd provides a lightweight runtime without the additional developer tools included in Docker.
• Kubernetes integration: It’s widely used as the default runtime for Kubernetes distributions like GKE, EKS, and AKS.
• OCI compliance: containerd is compatible with the Open Container Initiative (OCI) specifications.

containerd is best for teams optimizing performance and resource efficiency, especially in Kubernetes environments.

4. Buildah

Buildah is another of Red Hat’s open-source tools for building OCI-compliant container images. Unlike Docker, it focuses solely on image creation and management without requiring a runtime or daemon. 

Here’s what to know:

• Daemonless image building: Buildah eliminates the need for a background daemon, simplifying workflows.
• Rootless operation: Buildah increases security by allowing image creation without root privileges.
• Kubernetes integration: It works seamlessly with Kubernetes and other CRI-compliant runtimes.
• Integration with CI/CD Pipeline: Buildah was built to integrate with CI/CD pipelines for lightweight image building.

Buildah has a place in an ecosystem where developers are focused on secure and lightweight image-building pipelines.

5. LXD

LXD is a container and virtual machine manager developed by Canonical. It focuses on system containers, which are designed to run complete Linux distributions rather than individual applications. 

Teams searching for Docker alternatives may appreciate:

• System container support: LXD allows the running of full Linux environments, providing functionality similar to lightweight virtual machines.
• Hybrid capability: It supports both containers and virtual machines for flexible deployments.
• Efficiency: LXD combines the speed of containers with the isolation of VMs.

LXD is ideal for workloads requiring full operating system environments or hybrid container-VM deployments. 

6. Singularity

Singularity is a containerization platform tailored to high-performance computing (HPC) and research environments. Unlike Docker, it prioritizes reproducibility, security, and portability for scientific applications. 

Singularity includes features like:

• HPC optimization: Singularity is designed to run workloads on supercomputers, clusters, and cloud environments.
• Immutable containers: It ensures that containers are non-privileged and secure by design.
• Reproducibility: Singularity guarantees consistent performance across different environments.

Singularity is best for researchers and HPC environments requiring secure, reproducible containers. For data-intensive research and secure, collaborative environments, it’s an ideal support structure with a non-privileged execution model to ensure containerized applications run across platforms without exposing sensitive systems to unnecessary risks.

7. RKT

Rkt (pronounced “Rocket”) is a container runtime developed by CoreOS with a focus on security and modularity. Although discontinued in 2020, it introduced unique design principles still relevant in some legacy systems. 

Here’s why:

• Security-first design: RKT automatically signs and verifies containers to enhance trust.
• Daemonless execution: RKT avoids the need for a centralized daemon for simpler container execution.
• Early Kubernetes integration: It supported Kubernetes workloads before other runtimes became prominent.

Rkt is best for legacy systems or niche cases where its security and modularity are still relevant.

8. Kaniko

Kaniko is a tool designed to build container images securely in containerized environments, such as Kubernetes, without requiring privileged access. Unlike Docker, Kaniko executes builds entirely in userspace, avoiding the need for a Docker daemon. 

Here’s how its features might appeal to teams seeking Docker alternatives:

• Secure builds: Kaniko eliminates the need for root or privileged access for minimal potential attack surfaces.
• Cloud-native focus: Kaniko is designed to integrate seamlessly with Kubernetes and cloud CI/CD workflows.
• Builds in containers: Kaniko builds images directly inside Kubernetes pods or containers, so they’re automatically compatible with orchestrated environments.

Kaniko serves teams who want to build container images safely in cloud-native and multi-tenant environments.

9. AWS ECS/Fargate

AWS ECS (Elastic Container Service) and Fargate are managed containerization services provided by Amazon Web Services. Needless to say, they come deeply integrated with AWS tools and allow containerized applications to run without the need for a traditional runtime. 

Here are the advantages over Docker:

• Managed infrastructure: ECS and Fargate handle container hosting and scaling, reducing operational overhead.
• Serverless hosting: Fargate eliminates the need to manage servers or clusters.
• AWS integration: Both seamlessly integrate with AWS services like IAM, CloudWatch, and S3.

AWS ECS and Fargate are a logical alternative for teams heavily invested in the AWS ecosystem looking for a managed and scalable container hosting solution.

10. Azure Container Instances

Azure Container Instances (ACI) is Microsoft’s fully managed container service that allows developers to run containers without the complexity of provisioning or managing infrastructure. Designed for simplicity and rapid deployment, it works in scenarios where teams want to focus on applications rather than orchestration.

Here’s why ACI stands out as an alternative to Docker:

• Serverless simplicity: ACI lets teams run containers on-demand without managing virtual machines or orchestrators.
• Fast startup times: Containers can be deployed in seconds for more efficient workflows.
• Seamless Azure integration: ACI connects with Azure services like Azure Functions, Virtual Networks, and Azure Monitor.

Azure Container Instances are best for developers working in the Azure ecosystem.

11. Google Kubernetes Engine

Google Kubernetes Engine (GKE) is a fully managed Kubernetes service provided by Google Cloud. One of the earliest cloud-native solutions, GKE simplifies container orchestration by handling infrastructure provisioning, upgrades, and scaling.

Here’s how GKE appeals as a Docker alternative:

• Kubernetes expertise: Created by Google, GKE leverages Kubernetes’ full capabilities for seamless orchestration.
• Integrated ecosystem: GKE works with Google Cloud services like Anthos, BigQuery, and Cloud AI for advanced use cases.
• Autoscaling: GKE automatically scales clusters based on workloads, optimizing cost and performance.

Google Kubernetes Engine is best for organizations seeking a managed Kubernetes solution in the Google Cloud ecosystem.

How to Choose an Alternative to Docker

With so many containerization alternatives to Docker, teams need to evaluate their environments and resource needs before jumping ship. The best platform depends on factors like integration with existing systems, workload requirements, security, and scalability — and those are unique to organizations. Here are the key considerations to assess before finalizing a change. 

Kubernetes Compatibility

Teams relying on Kubernetes need container runtimes optimized for easy integration. Platforms like CRI-O and containerd were designed specifically for Kubernetes environments, focusing on lightweight operations and adhering to the Kubernetes Container Runtime Interface (CRI). They eliminate the overhead of extra features unrelated to Kubernetes. 

Similarly, Podman supports Kubernetes deployments through YAML generation for simplified orchestration. 

All three are particularly valuable for teams managing dynamic, large-scale workloads, where efficient container orchestration is key.

Security Needs

For environments where security is paramount, container platforms with strong isolation and reduced attack surfaces are top Docker alternatives.

Podman eliminates the need for a central daemon and supports rootless containers, improving operational security. Singularity caters to research and high-performance computing (HPC) scenarios with immutable, non-privileged containers, ensuring secure execution without compromising reproducibility. 

Both are good candidates for containerization in industries like healthcare, finance, and government, where compliance and data protection are key concerns.

Application Complexity

Applications with varying complexity need platforms that cater to their architectural needs. 

For workloads requiring full OS environments, LXD offers system containers that emulate lightweight virtual machines. On the other hand, Buildah creates images for simple, stateless applications without needing a full runtime or daemon. 

Teams dealing with hybrid or layered deployments may find LXD beneficial, while those focused on streamlined CI/CD pipelines should consider Buildah for its lightweight workflows.

Cloud Integration

Organizations heavily invested in cloud infrastructure may benefit most from integrated platforms like AWS ECS/Fargate, Azure Container Instances, or Google Kubernetes Engine. 

These services eliminate the need for on-premises infrastructure management and can offer deeply integrated solutions for various container services, from container hosting to scaling and orchestration, under one roof. Fargate’s serverless approach might be especially appealing for teams seeking to reduce operational overhead while leveraging the full suite of cloud-native tools, from monitoring to security and storage.

Legacy or Specialized Workloads

Legacy systems and niche use cases often require tailored solutions. 

Rkt, despite being discontinued, introduced a modular approach that has remained relevant in legacy infrastructures. For organizations with specialized needs, such as running complete Linux distributions alongside application containers, LXD offers hybrid container-VM setups. 

Both platforms provide the flexibility to maintain compatibility with existing workflows while modernizing infrastructure incrementally.

Resource Constraints

For environments with limited resources, such as IoT devices or edge computing, lightweight tools like Singularity and Buildah benefit teams the most. 

Singularity offers efficiency for scientific and research applications while minimizing resource overhead and ensuring reproducibility. Buildah, which focuses on image building without running containers, works in environments that prioritize minimalism. 

These three platforms let teams optimize deployments for resource use best — without sacrificing performance.

Focus on Building vs Running Containers

Docker and Podman combine both functionalities, but when replacing Docker, teams should consider whether their primary need is building container images or running and managing containers (or both).

Tools like Buildah and Kaniko excel at creating lightweight, OCI-compliant images for applications, making them ideal for teams prioritizing secure and efficient image-building pipelines in CI/CD workflows. 

On the other hand, runtimes like Podman, CRI-O, and containerd are optimized for executing and managing containers, especially in Kubernetes environments. 

Focusing on specialized tools can streamline workflows, reduce overhead, and improve security, but teams must trade off their one-stop solutions.

Upwind Protects Your Containers, No Matter Where they Operate

Upwind integrates container runtime security with cloud infrastructure security, offering protection at every stage of the container lifecycle — no matter which containerization platform you use to manage and deploy containers — and across clouds where workloads run. Across Kubernetes, Amazon ECS, and Fargate, teams can correlate runtime insights with build context, for total visibility into container threats.

Upwind protects your containers and Kubernetes with support for Amazon EKS & ECS, Google GKE, Microsoft AKS, OpenShift and more. To see it at work, schedule a demo.

FAQ

Is Docker being replaced?

In 2020, Kubernetes officially deprecated Docker as a container runtime, which has led to discussions about Docker’s relevance today. While Kubernetes no longer supports Docker as a runtime, Docker itself is not being replaced. However, its role in the container ecosystem is changing.

Kubernetes transitioned to the Container Runtime Interface (CRI) which supports other runtimes like containerd and CRI-O. So, while Docker images can still be used, the underlying runtime will not be Docker itself but rather alternatives that are lighter weight for Kubernetes operations. Despite the transition, many developers continue to use Docker locally, and tools like Docker Compose and Docker Desktop continue to be top developer choices.

Is Kubernetes an alternative to Docker?

Kubernetes is not an alternative to Docker, but rather a complementary tool that serves a different purpose in the container ecosystem. 

Docker focuses on creating, packaging, and running containers. With Dockers, developers build container images, run containers on a single host, and manage containerized applications.

With Kubernetes, developers deploy containers at scale, monitor container health, scale apps dynamically, and handle networking and load balancing between containers. Kubernetes originally relied on Docker as its default container runtime, though it now uses more lightweight alternatives.

What replaces a Docker machine?

Docker Machine was a tool used to provision and manage virtual machines (VMs) with Docker installed. Docker Machine helped with development, testing, and small-scale containerized deployments. It has since been deprecated, and there are several alternatives, including:

• Docker Desktop: A tool for running Docker on macOS, Linux, and Windows, it offers a local development environment without requiring manual VM setup. Docker Desktop effectively replaced Docker Machine for many use cases.
• Minikube
• Vagrant
• Kind
• Cloud Provider VM Instances
• Podman and Podman Machine 
• Custom Infrastructure-as-Code Scripts 

Can I run containers without Docker?

Yes. Docker is one popular containerization platform, but it’s not the only one. You can run containers using any of the 11 alternatives in this article. Alternatives to Docker typically focus on different aspects of containerization, excelling in specific areas. For instance, some alternatives emphasize improved container security, while others come with Kubernetes-native integration or lightweight runtimes.