Top 6 Docker Alternatives

The need for a Docker Alternative

Application containers such as Docker comes with their own security challenges:

• Kernel Vulnerabilities: Vulnerabilities that target the host system’s kernel may affect running containers.
• Misconfigurations: Improperly configured or otherwise vulnerable containers can be exploited by malicious actors, which risks exposing sensitive data or allowing unauthorized access.
• Compromised Images: Malicious code injected during the build process, or running within container images, can compromise the containerized application.

To mitigate these risks, use trusted and secure containers from reliable sources, control root access to containers, implement runtime security controls, and utilize network segmentation to isolate containers.

6 Docker Alternatives

Docker may not always be the right tool for the job. There are various container alternative technologies with their own unique advantages and disadvantages:

#1. Podman – Daemonless Docker Alternative

Because Podman doesn’t require a daemon, it lets developers run containers as a non-root user, reducing the attack surface. It offers a command line interface similar to that of Docker, easing the difficulty of transition. Its architecture improves network isolation, has secure defaults, and supports SELinux.

Because Podman is relatively new compared to Docker, its smaller ecosystem limits the number of images and tools available.

The bottom line: Podman is a viable alternative for organizations seeking Linux-native tooling and higher security in containerization workflows.

#2. Containerd – OCI Complaint Standardization & Scalability

An industry-standard, lightweight container runtime that follows the Open Container Initiative (OCI) standard method of managing containers across virtual environments. containerd serves as the runtime foundation for other containerization interfaces, including both Docker and Podman, and is also compatible with Kubernetes. Its small footprint, scalability and support for multiple orchestrators are key advantages.

However its simple architecture lacks the more robust features found in higher-level containerization alternatives, while its minimalistic design makes it less ideal for new users.

The bottom line: containerd is best utilized by organizations with experienced container users with a need for OCI-compliant standardization and scalability.

#3. CRI-O – High Performance Kubernetes Integration

CRI-O is an implementation of the Kubernetes Container Runtime Interface (CRI). It is a high performance container runtime with a focus on speed and efficiency for production use cases, and is designed specifically for use in a Kubernetes security setting. CRI-O provides strong security features, including support for AppArmor and seccomp.

Because CRI-O focuses exclusively on the Kubernetes ecosystem, it naturally has a narrower scope of environment compatibility, with limited support for other orchestration tools.

The bottom line: CRI-O’s high performance and seamless Kubernetes integration makes it a strong contender for organizations working on that platform.

#4. LXC – Lightweight Virtualization Solution

LXC (Linux Containers) is a lightweight virtualization solution that provides strong process isolation and control when compared to other container runtimes. LXC focuses on fine-grained control over system resources, enhanced security and flexibility, and easy container snapshots and backups.

LXC has a smaller ecosystem compared to Docker. Its flexibility comes at the cost of a steeper learning curve, with higher setup complexity compared to other container technologies. The availability of LXD, an Ubuntu-specific container management tool built on top of LXC, somewhat mitigates this complexity.

The bottom line: LXC is best suited for developers who desire granular control over their containers and is particularly suited for Ubuntu environments.

#5. runc: – Low-Level Command Line Tool

This is a low-level command line tool for running containers, and is compatible with the OCI runtime specification. It is used by various other container runtimes, including both Docker and containerd. Its simplicity and minimalism make it fast and light on resource usage, while being easy to understand and manage.

On the downside, runc lacks many of the capabilities found in full-featured applications like Docker or Podman, and beginners may find its minimalistic design challenging to learn.

The bottom line: runc is appropriate for advanced container users seeking a lightweight runtime for running OCI-compliant containers.

#6. rkt: – Native Pod Support

Pronounced “rocket,” rkt natively supports running multiple containers together as a single entity called a pod. It allows for users to create complex container setups using composable building blocks, and its reliance on Linux namespaces and cgroups allows for strong process isolation. rkt is also an OCI-compatible runtime.

rkt’s focus on security and isolation make it more daunting for non-technical users, and its advanced featureset make for a more challenging configuration and management outlook. rkt also de-emphasizes compatibility with Kubernetes.

The bottom line: rkt is an attractive option for organizations with experienced users that have requirements for native pod support, high security, and easy integration into larger systems.