Linkerd and SMI

sound mixer board

Earlier this week at Kubecon EU, Microsoft announced the Service Mesh Interface (SMI). SMI is a specification that exposes core service mesh features like telemetry, traffic shifting, and policy, purely via Kubernetes primitives.

The Linkerd community has been working heavily with our friends from Microsoft and Hashicorp on SMI for the past few months. In fact, the top two contributors to SMI are Linkerd’s Thomas Rampelberg and Hashicorp’s Nick Jackson—a healthy sign of serious community involvement.

SMI contributors graph

The reason we’ve invested so much time and energy in SMI is that we believe it will significantly opens up the ecosystem of tools and products built top of the service mesh. With SMI, awesome tools like Flagger, Kubecost, and Kiali can build on SMI rather than tying their implementation to a specific mesh. This is great for Linkerd users and great for the community as a whole.

Linkerd 2.3 already implements SMI’s Traffic Metrics spec. In next month’s 2.4, we’ll add support for Traffic Split (which means that, yes, next month Linkerd will support traffic shifting for canaries and blue-green deploys!), and in later releases we’ll flesh out Linkerd’s support for the remaining SMI interfaces.

Linkerd is the fastest, lightest, simplest service mesh in the world, and we’re excited about SMI’s ability to bring Linkerd to even more users around the globe.


Linkerd is a community project and is hosted by the Cloud Native Computing Foundation. If you have feature requests, questions, or comments, we’d love to have you join our rapidly-growing community! Linkerd is hosted on GitHub, and we have a thriving community on Slack, Twitter, and the mailing lists. Come and join the fun!

Image credit: I G