Linkerd

Free plan LinuxSelf-hosted

What Linkerd is

Linkerd is a free service mesh for Kubernetes that adds debugging, observability, reliability, and security at runtime without code changes. It is installed in a Kubernetes cluster, where it injects sidecar proxies into workloads. It handles HTTP, HTTP/2, gRPC, and arbitrary TCP traffic, including TLS connections and WebSockets. Linkerd enables mutual TLS between meshed applications and supports authorization policies between services. It records request volume, success rates, and latency distributions for HTTP, HTTP/2, and gRPC, as well as TCP metrics. Traffic controls include load balancing, retries, timeouts, dynamic routing, traffic splitting, and rate limiting. Linkerd can work with Prometheus and Grafana and supports distributed tracing. Its included Linkerd Viz Prometheus retains metrics for six hours, so it is intended to complement an existing metrics store. Installation needs a modern Kubernetes cluster and a working kubectl command. The project is Apache 2.0 licensed; Buoyant offers commercial support, training, and architectural reviews.

Who it suits

Linkerd suits teams running Kubernetes workloads that need service-level traffic controls, metrics, or mutual TLS. Its six-hour included metrics retention makes it relevant to teams with an existing metrics store.

What it does well

Free, Apache 2.0-licensed open-source plan.
Supports HTTP, HTTP/2, gRPC, TCP, and WebSockets.
Enables mutual TLS and service authorization policies.
Includes retries, timeouts, traffic splitting, and rate limiting.

What to know first

Requires a modern Kubernetes cluster and kubectl.
Included metrics retention is six hours.
Not a standalone metrics store replacement.

Limits

Linkerd requires a modern Kubernetes cluster and a functioning kubectl command. The Prometheus instance included with Linkerd Viz retains metrics for six hours, and Linkerd is designed to supplement an existing metrics store.

Plans

Plan	Billed and limits	Price
Linkerd open source	Open source, Apache 2.0 licensed · Requires Kubernetes	Free

As linkerd.io lists them, read 29 Sept 2026. The maker's own page has the final word.

Getting started

Prepare a modern Kubernetes cluster.
Ensure kubectl is functioning.
Install Linkerd into the cluster.
Inject Linkerd proxies into the workload pods you want meshed.
Connect Prometheus or Grafana for metrics and dashboards, if needed.

Verdict

Linkerd offers traffic management, observability, and security for Kubernetes without requiring code changes. Its included metrics retention is short, so it is designed to supplement an existing metrics store.

Questions

Is Linkerd free?

Yes. The listed open-source plan is free and is licensed under Apache 2.0.

What does Linkerd run on?

Linkerd is for Kubernetes and requires a modern Kubernetes cluster. The listed platforms are Linux and self-hosted.

What traffic does Linkerd support?

It supports HTTP, HTTP/2, gRPC, and arbitrary TCP traffic, including TLS connections and WebSockets.

Does Linkerd provide mutual TLS?

Yes. It automatically enables mutual TLS between meshed applications and supports authorization policies between services.

How long does Linkerd Viz retain metrics?

Its included Prometheus instance retains metrics for six hours. Linkerd is designed to supplement an existing metrics store.

Is Linkerd open source?

Yes. Linkerd is a CNCF graduated project licensed under Apache 2.0. Buoyant offers commercial support, training, and architectural reviews.

Facts from Linkerd's own pages

Commercial support: Buoyant offers 24x7 enterprise support, training, and architectural reviews for Linkerd. · linkerd.io, 29 Sept 2026
Deployment: Linkerd is installed into a Kubernetes cluster and adds its data plane to workloads by injecting proxies into their pods. · linkerd.io, 29 Sept 2026
Enterprise distribution: Buoyant Enterprise for Linkerd lists a FIPS-compliant distribution with full L7 visibility and network encryption, authentication, and authorization. · linkerd.io, 29 Sept 2026
Governance: Linkerd is a CNCF graduated project licensed under Apache 2.0. · linkerd.io, 29 Sept 2026
Integrations: Linkerd can use Prometheus and Grafana for metrics and dashboards, and supports distributed tracing. · linkerd.io, 29 Sept 2026
Metrics retention: The Prometheus instance included with Linkerd Viz retains metrics for a short fixed interval, currently six hours, and Linkerd is designed to supplement an existing metrics store. · linkerd.io, 29 Sept 2026
Observability: Linkerd records request volume, success rates, and latency distributions for HTTP, HTTP/2, and gRPC traffic, plus TCP-level metrics. · linkerd.io, 29 Sept 2026
Product: Linkerd is a service mesh for Kubernetes that adds runtime debugging, observability, reliability, and security without requiring code changes. · linkerd.io, 29 Sept 2026
Proxy: Linkerd’s ultralight Linkerd2-proxy is written in Rust and designed specifically for the service mesh sidecar use case. · linkerd.io, 29 Sept 2026
Requirements: Linkerd requires a modern Kubernetes cluster and a functioning kubectl command for installation. · linkerd.io, 29 Sept 2026
Security: Linkerd automatically enables mutual TLS for communication between meshed applications and supports authorization policies between services. · linkerd.io, 29 Sept 2026
Security audit: Linkerd says it completed its 2024 security audit, which included penetration testing and white-box testing. · linkerd.io, 29 Sept 2026
Traffic management: Linkerd supports load balancing, retries, timeouts, dynamic request routing, traffic splitting, and rate limiting. · linkerd.io, 29 Sept 2026
Traffic support: Linkerd proxies HTTP, HTTP/2, gRPC, and arbitrary TCP traffic, including TLS connections and WebSockets. · linkerd.io, 29 Sept 2026

Where Linkerd stands on Freedom251

Service Mesh Platforms#8 of 22
Distributed Systems#22 of 30