Emissary-ingress
================

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[Emissary-Ingress](https://www.getambassador.io) is an open-source Kubernetes-native API Gateway +
Layer 7 load balancer + Kubernetes Ingress built on [Envoy Proxy](https://www.envoyproxy.io).
Emissary-ingress is a CNCF incubation project (and was formerly known as Ambassador API Gateway).

Emissary-ingress enables its users to:
* Manage ingress traffic with [load balancing], support for multiple protocols ([gRPC and HTTP/2], [TCP], and [web sockets]), and Kubernetes integration
* Manage changes to routing with an easy to use declarative policy engine and [self-service configuration], via Kubernetes [CRDs] or annotations
* Secure microservices with [authentication], [rate limiting], and [TLS]
* Ensure high availability with [sticky sessions], [rate limiting], and [circuit breaking]
* Leverage observability with integrations with [Grafana], [Prometheus], and [Datadog], and comprehensive [metrics] support
* Enable progressive delivery with [canary releases]
* Connect service meshes including [Consul], [Linkerd], and [Istio]
* [Knative serverless integration]

See the full list of [features](https://www.getambassador.io/features/) here.

Branches
========

(If you are looking at this list on a branch other than `master`, it
may be out of date.)

- [`master`](https://github.com/emissary-ingress/emissary/tree/master) - branch for Emissary-ingress 3.2.z work (:heavy_check_mark: upcoming release)
- [`release/v3.1`](https://github.com/emissary-ingress/emissary/tree/release/v3.1) - branch for Emissary-ingress 3.1.z work (:heavy_check_mark: current latest)
- [`release/v3.0`](https://github.com/emissary-ingress/emissary/tree/release/v3.0) - branch for Emissary-ingress 3.0.z work (:x: EOL; upgrade to 3.1.z)
- [`release/v2.4`](https://github.com/emissary-ingress/emissary/tree/release/v2.4) - branch for Emissary-ingress 2.4.z work (:heavy_check_mark: upcoming release)
- [`release/v2.3`](https://github.com/emissary-ingress/emissary/tree/release/v2.3) - branch for Emissary-ingress 2.3.z work (:heavy_check_mark: maintenance, supported through December 2022)
- [`release/v2.2`](https://github.com/emissary-ingress/emissary/tree/release/v2.2) - branch for Emissary-ingress 2.2.z work (:x: EOL; upgrade to 2.3.z)
- [`release/v2.1`](https://github.com/emissary-ingress/emissary/tree/release/v2.1) - branch for Emissary-ingress 2.1.z work (:x: EOL; upgrade to 2.3.z)
- [`release/v2.0`](https://github.com/emissary-ingress/emissary/tree/release/v2.0) - branch for Emissary-ingress 2.0.z work (:x: EOL; upgrade to 2.3.z)
- [`release/v1.14`](https://github.com/emissary-ingress/emissary/tree/release/v1.14) - branch for Emissary-ingress 1.14.z work (:heavy_check_mark: maintenance, supported through September 2022)
- [`release/v1.13`](https://github.com/emissary-ingress/emissary/tree/release/v1.13) - branch for Emissary-ingress 1.13.z work (:x: EOL; upgrade to 1.14.z)
- [`release/v1.12`](https://github.com/emissary-ingress/emissary/tree/release/v1.12) - branch for Ambassador API Gateway 1.12.z work (:x: EOL; upgrade to 1.14.z)
- [`release/v1.11`](https://github.com/emissary-ingress/emissary/tree/release/v1.11) - branch for Ambassador API Gateway 1.11.z work (:x: EOL; upgrade to 1.14.z)
- [`release/v1.10`](https://github.com/emissary-ingress/emissary/tree/release/v1.10) - branch for Ambassador API Gateway 1.10.z work (:x: EOL; upgrade to 1.14.z)
- [`release/v1.9`](https://github.com/emissary-ingress/emissary/tree/release/v1.9) - branch for Ambassador API Gateway 1.9.z work (:x: EOL; upgrade to 1.14.z)
- [`release/v1.8`](https://github.com/emissary-ingress/emissary/tree/release/v1.8) - branch for Ambassador API Gateway 1.8.z work (:x: EOL; upgrade to 1.14.z)
- [`release/v1.7`](https://github.com/emissary-ingress/emissary/tree/release/v1.7) - branch for Ambassador API Gateway 1.7.z work (:x: EOL; upgrade to 1.14.z)
- [`release/v1.6`](https://github.com/emissary-ingress/emissary/tree/release/v1.6) - branch for Ambassador API Gateway 1.6.z work (:x: EOL; upgrade to 1.14.z)
- [`release/v1.5`](https://github.com/emissary-ingress/emissary/tree/release/v1.5) - branch for Ambassador API Gateway 1.5.z work (:x: EOL; upgrade to 1.14.z)
- [`release/v1.4`](https://github.com/emissary-ingress/emissary/tree/release/v1.4) - branch for Ambassador API Gateway 1.4.z work (:x: EOL; upgrade to 1.14.z)
- [`release/v1.3`](https://github.com/emissary-ingress/emissary/tree/release/v1.3) - branch for Ambassador API Gateway 1.3.z work (:x: EOL; upgrade to 1.14.z)
- [`release/v1.2`](https://github.com/emissary-ingress/emissary/tree/release/v1.2) - branch for Ambassador API Gateway 1.2.z work (:x: EOL; upgrade to 1.14.z)
- [`release/v1.1`](https://github.com/emissary-ingress/emissary/tree/release/v1.1) - branch for Ambassador API Gateway 1.1.z work (:x: EOL; upgrade to 1.14.z)

Architecture
============

Emissary is configured via Kubernetes CRDs, or via annotations on Kubernetes `Service`s. Internally,
it uses the [Envoy Proxy] to actually handle routing data; externally, it relies on Kubernetes for
scaling and resiliency. For more on Emissary's architecture and motivation, read [this blog post](https://blog.getambassador.io/building-ambassador-an-open-source-api-gateway-on-kubernetes-and-envoy-ed01ed520844).

Getting Started
===============

You can get Emissary up and running in just three steps. Follow the instructions here: https://www.getambassador.io/docs/emissary/latest/tutorials/getting-started/

If you are looking for a Kubernetes ingress controller, Emissary provides a superset of the functionality of a typical ingress controller. (It does the traditional routing, and layers on a raft of configuration options.) This blog post covers [Kubernetes ingress](https://blog.getambassador.io/kubernetes-ingress-nodeport-load-balancers-and-ingress-controllers-6e29f1c44f2d).

For other common questions, view this [FAQ page](https://www.getambassador.io/docs/emissary/latest/about/faq/).

You can also use Helm to install Emissary. For more information, see the instructions in the [Helm installation documentation](https://www.getambassador.io/docs/emissary/latest/topics/install/helm/)

Community
=========

Emissary-ingress is a CNCF Incubating project and welcomes any and all contributors. To get started:

* Join our [Slack channel](https://a8r.io/slack)
* Check out the [Emissary documentation](https://www.getambassador.io/docs/emissary/)
* Read the [Contributor's Guide](https://github.com/emissary-ingress/emissary/blob/master/DEVELOPING.md).

If you're interested in contributing, here are some ways:

* Write a blog post for [our blog](https://blog.getambassador.io)
* Investigate an [open issue](https://github.com/emissary-ingress/emissary/issues)
* Add [more tests](https://github.com/emissary-ingress/emissary/tree/master/ambassador/tests)

The Ambassador Edge Stack is a superset of Emissary-ingress that provides additional functionality including OAuth/OpenID Connect, advanced rate limiting, Swagger/OpenAPI support, integrated ACME support for automatic TLS certificate management, and a cloud-based UI. For more information, visit https://www.getambassador.io/editions/.

<!-- Please keep this list sorted. -->
[authentication]: https://www.getambassador.io/docs/emissary/latest/topics/running/services/auth-service/
[canary releases]: https://www.getambassador.io/docs/emissary/latest/topics/using/canary/
[circuit breaking]: https://www.getambassador.io/docs/emissary/latest/topics/using/circuit-breakers/
[Consul]: https://www.getambassador.io/docs/emissary/latest/howtos/consul/
[CRDs]: https://kubernetes.io/docs/concepts/extend-kubernetes/api-extension/custom-resources/
[Datadog]: https://www.getambassador.io/docs/emissary/latest/topics/running/statistics/#datadog
[Grafana]: https://www.getambassador.io/docs/emissary/latest/topics/running/statistics/#grafana
[gRPC and HTTP/2]: https://www.getambassador.io/docs/emissary/latest/howtos/grpc/
[Istio]: https://www.getambassador.io/docs/emissary/latest/howtos/istio/
[Knative serverless integration]: https://www.getambassador.io/docs/emissary/latest/howtos/knative/
[Linkerd]: https://www.getambassador.io/docs/emissary/latest/howtos/linkerd2/
[load balancing]: https://www.getambassador.io/docs/emissary/latest/topics/running/load-balancer/
[metrics]: https://www.getambassador.io/docs/emissary/latest/topics/running/statistics/
[Prometheus]: https://www.getambassador.io/docs/emissary/latest/topics/running/statistics/#prometheus
[rate limiting]: https://www.getambassador.io/docs/emissary/latest/topics/running/services/rate-limit-service/
[self-service configuration]: https://www.getambassador.io/docs/emissary/latest/topics/using/mappings/
[sticky sessions]: https://www.getambassador.io/docs/emissary/latest/topics/running/load-balancer/#sticky-sessions--session-affinity
[TCP]: https://www.getambassador.io/docs/emissary/latest/topics/using/tcpmappings/
[TLS]: https://www.getambassador.io/docs/emissary/latest/howtos/tls-termination/
[web sockets]: https://www.getambassador.io/docs/emissary/latest/topics/using/tcpmappings/
