Why Emissary?

Emissary gives platform engineers a comprehensive, self-service edge stack for managing the boundary between end-users and Kubernetes. Built on the Envoy Proxy and fully Kubernetes-native, Emissary is made to support multiple, independent teams that need to rapidly publish, monitor, and update services for end-users. A true edge stack, Emissary can also be used to handle the functions of an API Gateway, a Kubernetes ingress controller, and a layer 7 load balancer (for more, see this blog post).

How Does Emissary work?

Emissary is an open-source, Kubernetes-native microservices API gateway built on the Envoy Proxy. Emissary is built from the ground up to support multiple, independent teams that need to rapidly publish, monitor, and update services for end-users. Emissary can also be used to handle the functions of a Kubernetes ingress controller and load balancer (for more, see this blog post).

Cloud-native applications today

Traditional cloud applications were built using a monolithic approach. These applications were designed, coded, and deployed as a single unit. Today’s cloud-native applications, by contrast, consist of many individual (micro)services. This results in an architecture that is:

• Heterogeneous: Services are implemented using multiple (polyglot) languages, they are designed using multiple architecture styles, and they communicate with each other over multiple protocols.
• Dynamic: Services are frequently updated and released (often without coordination), which results in a constantly-changing application.
• Decentralized: Services are managed by independent product-focused teams, with different development workflows and release cadences.

Heterogeneous services

Emissary is commonly used to route traffic to a wide variety of services. It supports:

• configuration on a per-service basis, enabling fine-grained control of timeouts, rate limiting, authentication policies, and more.
• a wide range of L7 protocols natively, including HTTP, HTTP/2, gRPC, gRPC-Web, and WebSockets.
• Can route raw TCP for services that use protocols not directly supported by Emissary.

Dynamic services

Service updates result in a constantly changing application. The dynamic nature of cloud-native applications introduces new challenges around configuration updates, release, and testing. Emissary:

• Enables progressive delivery, with support for canary routing and traffic shadowing.
• Exposes high-resolution observability metrics, providing insight into service behavior.
• Uses a zero downtime configuration architecture, so configuration changes have no end-user impact.

Decentralized workflows

Independent teams can create their own workflows for developing and releasing functionality that are optimized for their specific service(s). With Emissary, teams can:

• Leverage a declarative configuration model, making it easy to understand the canonical configuration and implement GitOps-style best practices.
• Independently configure different aspects of Emissary, eliminating the need to request configuration changes through a centralized operations team.

Emissary is engineered for Kubernetes

Emissary takes full advantage of Kubernetes and Envoy Proxy.

• All of the state required for Emissary is stored directly in Kubernetes, eliminating the need for an additional database.
• The Emissary team has added extensive engineering efforts and integration testing to ensure optimal performance and scale of Envoy and Kubernetes.

For more information

Deploy Emissary today and join the community Slack Channel.

Interested in learning more?

• Why did we start building Emissary?
• Emissary Architecture overview