About Calico

What is Calico?

Calico is an open source networking and network security solution for containers, virtual machines, and native host-based workloads. Calico supports a broad range of platforms including Kubernetes, OpenShift, Docker EE, OpenStack, and bare metal services.

Calico combines flexible networking capabilities with run-anywhere security enforcement to provide a solution with native Linux kernel performance and true cloud-native scalability. Calico provides developers and cluster operators with a consistent experience and set of capabilities whether running in public cloud or on-prem, on a single node or across a multi-thousand node cluster.

Why use Calico?

Best practices for network security

Calico’s rich network policy model makes it easy to lock down communication so the only traffic that flows is the traffic you want to flow. You can think of Calico’s security enforcement as wrapping each of your workloads with its own personal firewall that is dynamically re-configured in real time as you deploy new services or scale your application up or down.

Calico’s policy engine can enforce the same policy model at the host networking layer and (if using Istio & Envoy) at the service mesh layer, protecting your infrastructure from compromised workloads and protecting your workloads from compromised infrastructure.


Calico uses the Linux kernel’s built-in highly optimized forwarding and access control capabilities to deliver native Linux networking dataplane performance, typically without requiring any of the encap/decap overheads associated with first generation SDN networks. Calico’s control plane and policy engine has been fine tuned over many years of production use to minimize overall CPU usage and occupancy.


Calico’s core design principles leverage best practice cloud-native design patterns combined with proven standards based network protocols trusted worldwide by the largest internet carriers. The result is a solution with exceptional scalability that has been running at scale in production for years. Calico’s development test cycle includes regularly testing multi-thousand node clusters. Whether you are running a 10 node cluster, 100 node cluster, or more, you reap the benefits of the improved performance and scalability characteristics demanded by the largest Kubernetes clusters.


Calico enables Kubernetes workloads and non-Kubernetes or legacy workloads to communicate seamlessly and securely. Kubernetes pods are first class citizens on your network and able to communicate with any other workload on your network. In addition Calico can seamlessly extend to secure your existing host based workloads (whether in public cloud or on-prem on VMs or bare metal servers) alongside Kubernetes. All workloads are subject to the same network policy model so the only traffic that is allowed to flow is the traffic you expect to flow.

Looks familiar

Calico uses the Linux primitives that existing system administrators are already familiar with. Type in your favorite Linux networking command and you’ll get the results you expect. In the vast majority of deployments the packet leaving your application is the packet that goes on the wire, with no encapsulation, tunnels, or overlays. All the existings tools that system and network administrators use to gain visibility and analyze networking issues work as they do today.

Real world production hardened

Calico is trusted and running in production at large enterprises including SaaS providers, financial services companies, and manufacturers. The largest public cloud providers have selected Calico to provide network security for their hosted Kubernetes services (Amazon EKS, Azure AKS, Google GKE, and IBM IKS) running across tens of thousands of clusters.

Full Kubernetes network policy support

Calico’s network policy engine formed the original reference implementation of Kubernetes network policy during the development of the API. Calico is distinguished in that it implements the full set of features defined by the API giving users all the capabilities and flexibility envisaged when the API was defined. And for users that require even more power, Calico supports an extended set of network policy capabilities that work seamlessly alongside the Kubernetes API giving users even more flexibility in how they define their network policies.

A contributor community backed by the Tigera team

The Calico open source project has been supported by 150+ contributors across a broad range of companies. In addition Calico is backed by Tigera, founded by the original Calico engineering team, and committed to maintaining Calico as the leading standard for Kubernetes network security.