Calico Open Source vs CNI Plugins

Calico Open Source provides networking, network security, and observability for Kubernetes across multi-cloud, hybrid-cloud, and on-premises environments. It supports container, virtual machine, and bare-metal workloads with a shared security policy framework. The policy engine implements Kubernetes network policy features including AdminNetworkPolicy and BaselineAdminNetworkPolicy. Policies can use tiers, deny and log actions, NetworkSets, and cluster-wide global rules; Staged Policies allow teams to assess behavior before applying enforcement. Listed data planes include eBPF, iptables, nftables, Windows, and VPP. Whisker provides a visual way to view flow logs and analyze network communication. Calico can also manage WireGuard tunnels to encrypt pod traffic between Kubernetes nodes. Calico Ingress Gateway provides traffic control, load balancing, and ingress policy enforcement. The free plan includes unlimited clusters, with in-memory data retention and community-driven support and maintenance. Tigera describes deployments ranging from 10 to 10,000 or more nodes.

CNI Plugins is a collection of reference and example network plugins for configuring connectivity in Linux and Windows containers. CNI supplies a specification and libraries, plus a command-line tool for executing plugins and a Go library for application integration. Interface options include bridge, ipvlan, loopback, macvlan, point-to-point, VLAN, host-device, and dummy; Windows-specific plugins include win-bridge and win-overlay. IP address management choices cover DHCP, host-local allocation tracking, and static IPv4 or IPv6 allocation. Meta plugins handle interface tuning, port mapping, bandwidth limits, source-based routing, and firewall rules, and a sample plugin illustrates custom plugin development. CNI focuses on connecting containers and removing allocated resources when a container is deleted. The project is distributed under Apache License 2.0 and is a Cloud Native Computing Foundation project. It is free, with a plan listed at free. Linux and Windows are supported; the latest release page lists Linux archives for amd64, arm, and arm64.