CNI Plugins

CNI Plugins suits teams that need configurable building blocks for Linux and Windows container networking, or developers integrating CNI into an application. Its breadth and free Apache 2.0 license make it a strong foundation; teams wanting a complete, ready-made networking system should look elsewhere.

Overview

CNI provides a specification and libraries for configuring network interfaces in containers, with plugins that carry out that work. The project also supplies a Go library for application integration and a command-line tool for executing plugins. Together, these pieces suit operators assembling a network setup and developers embedding CNI, but they leave component selection and composition to the team.

The scope is focused: connect containers to networks and remove allocated resources when a container is deleted. As a Cloud Native Computing Foundation project distributed under the Apache License, Version 2.0, CNI Plugins is a practical choice for teams that value open, adaptable components over a single product with a prescribed workflow.

Key features

Interface plugins cover bridge, ipvlan, loopback, macvlan, point-to-point, VLAN, host-device and dummy networking. This gives teams several ways to configure container interfaces, though the range is most useful when someone can choose the right components for the environment.

IPAM options include DHCP, host-local allocation tracking and static IPv4 or IPv6 allocation. That variety supports different address-management needs, while still requiring operators to settle on an allocation approach and fit it into their setup.

Meta plugins add interface tuning, port mapping, bandwidth limiting, source-based routing and firewall rules. These extend the collection beyond basic interface creation, but do not turn it into a complete network-management product. A sample plugin also gives developers an example to work from when building a custom plugin.

Windows-specific win-bridge and win-overlay plugins extend the project to Windows containers. The latest release page provides downloadable Linux archives, including amd64, arm and arm64 builds; Windows users therefore have platform-specific components, while the named downloadable archives are Linux builds.

The project asks security reporters to contact the email addresses in its OWNERS file privately. Questions go to the cni-dev mailing group or the #cni channel on CNCF Slack.

Pricing

Free — free. The plan includes reference and example CNI network plugins under the Apache-2.0 license. There is no free trial, because the software is offered as a free plan. With no paid tier described, the central trade-off is not feature gating by price but the effort of selecting and integrating the components.

Platforms

CNI Plugins supports Linux and Windows. Linux release archives are available for amd64, arm and arm64; Windows support is represented by win-bridge and win-overlay plugins.

Who it's for

CNI Plugins is best for platform teams choosing networking and IPAM components for containers, and developers who want a Go library and command-line tool to integrate or run CNI. Its interface, IPAM and meta-plugin options reward teams that need flexibility and can make integration decisions. It is a weaker fit for buyers who want one packaged networking system with a turnkey operational model.

Pros and cons

• Pros: A broad choice of interface plugins and IPAM methods lets teams build around their container networking needs.
• Pros: The Go library, execution tool and sample plugin support both application integration and custom development.
• Pros: Free availability under Apache 2.0 keeps the components open to use and adapt.
• Cons: Teams must choose and combine plugins themselves, so the breadth brings configuration and integration responsibility.
• Cons: Linux release downloads are specified for Linux architectures; Windows users must work with the Windows-specific plugins.

Alternatives

For other options, browse Container Networking Software.

• Canal is another free Apache-2.0 project, with API, Linux, macOS and self-hosted platforms; consider it if those platforms better match your requirements.
• VMware Workstation Pro is free for Windows or Linux hosts on 64-bit Intel or AMD PCs, with no subscription or license key required; choose it when that host-software scope fits instead of CNI components.
• Antrea is a free Apache License 2.0 option for Linux, Windows and self-hosted use, but requires a Kubernetes cluster and Open vSwitch kernel module on every Kubernetes node.
• Calico Open Source offers community-driven support and maintenance, in-memory data retention and unlimited clusters; consider it when those stated characteristics are a better fit.
• Flannel is a free, Apache 2.0 open-source Kubernetes networking project; choose it if that project scope suits your needs.
• kube-network-policies is a free Kubernetes network policy implementation installable with raw manifests or Helm; pick it when network policy is the requirement.
• Cello CNI is a free Apache 2.0 option that requires Volcengine ECS, Kubernetes and Helm 3.0; choose it only if those requirements fit.
• Cilium is a free open-source Linux option requiring kernel 5.10 or equivalent and AMD64 or AArch64; consider it if that platform and requirement set works for you.

Verdict

Choose CNI Plugins if you need open, adaptable components to configure container interfaces, manage IP allocation or integrate CNI into software. Its range and free Apache 2.0 license are the main reasons to choose it; look elsewhere if you want a ready-made networking product rather than a collection you must assemble.