Documentation for Ingress (#6378)

Signed-off-by: Alvaro Saurin <alvaro.saurin@gmail.com>

README.md

@@ -132,6 +132,7 @@ Note: Upstart/SysV init based OS types are not supported.
   - [multus](https://github.com/intel/multus-cni) v3.6.0
   - [weave](https://github.com/weaveworks/weave) v2.6.5
 - Application
+  - [ambassador](https://github.com/datawire/ambassador): v1.5
   - [cephfs-provisioner](https://github.com/kubernetes-incubator/external-storage) v2.1.0-k8s1.11
   - [rbd-provisioner](https://github.com/kubernetes-incubator/external-storage) v2.1.1-k8s1.11
   - [cert-manager](https://github.com/jetstack/cert-manager) v0.11.1
@@ -197,6 +198,12 @@ The choice is defined with the variable `kube_network_plugin`. There is also an
 option to leverage built-in cloud provider networking instead.
 See also [Network checker](docs/netcheck.md).
 
+## Ingress Plugins
+
+- [ambassador](docs/ambassador.md): the Ambassador Ingress Controller and API gateway.
+
+- [nginx](https://kubernetes.github.io/ingress-nginx): the NGINX Ingress Controller.
+
 ## Community docs and resources
 
 - [kubernetes.io/docs/setup/production-environment/tools/kubespray/](https://kubernetes.io/docs/setup/production-environment/tools/kubespray/)

docs/_sidebar.md

@@ -17,6 +17,8 @@
   * [Kube Router](docs/kube-router.md)
   * [Weave](docs/weave.md)
   * [Multus](docs/multus.md)
+* Ingress
+  * [Ambassador](docs/ambassador.md)
 * [Cloud providers](docs/cloud.md)
   * [AWS](docs/aws.md)
   * [Azure](docs/azure.md)

docs/ambassador.md

@@ -0,0 +1,86 @@
+
+# Ambassador
+
+The Ambassador API Gateway provides all the functionality of a traditional ingress controller
+(e.g., path-based routing) while exposing many additional capabilities such as authentication,
+URL rewriting, CORS, rate limiting, and automatic metrics collection.
+
+## Installation
+
+### Configuration
+
+* `ingress_ambassador_namespace` (default `ambassador`): namespace for installing Ambassador.
+* `ingress_ambassador_update_window` (default `0 0 * * SUN`): _crontab_-like expression
+  for specifying when the Operator should try to update the Ambassador API Gateway.
+* `ingress_ambassador_version` (defaulkt: `*`): SemVer rule for versions allowed for
+  installation/updates.
+* `ingress_ambassador_secure_port` (default: 443): HTTPS port to listen at.
+* `ingress_ambassador_insecure_port` (default: 80): HTTP port to listen at.
+
+### Ambassador Operator
+
+This Ambassador addon deploys the Ambassador Operator, which in turn will install Ambassador in
+a Kubernetes cluster.
+
+The Ambassador Operator is a Kubernetes Operator that controls Ambassador's complete lifecycle
+in your cluster, automating many of the repeatable tasks you would otherwise have to perform
+yourself.  Once installed, the Operator will complete installations and seamlessly upgrade to new
+versions of Ambassador as they become available.
+
+## Usage
+
+The following example creates simple http-echo services and an `Ingress` object
+to route to these services.
+
+Note well that the Ambassador API Gateway will automatically load balance `Ingress` resources
+that include the annotation `kubernetes.io/ingress.class=ambassador`. All the other
+resources will be just ignored.
+
+```yaml
+kind: Pod
+apiVersion: v1
+metadata:
+  name: foo-app
+  labels:
+    app: foo
+spec:
+  containers:
+  - name: foo-app
+    image: hashicorp/http-echo
+    args:
+    - "-text=foo"
+---
+kind: Service
+apiVersion: v1
+metadata:
+  name: foo-service
+spec:
+  selector:
+    app: foo
+  ports:
+  # Default port used by the image
+  - port: 5678
+---
+apiVersion: extensions/v1beta1
+kind: Ingress
+metadata:
+  name: example-ingress
+  annotations:
+    kubernetes.io/ingress.class: ambassador
+spec:
+  rules:
+  - http:
+      paths:
+      - path: /foo
+        backend:
+          serviceName: foo-service
+          servicePort: 5678
+```
+
+Now you can test that the ingress is working with curl:
+
+```console
+$ export AMB_IP=$(kubectl get service ambassador -n ambassador -o 'go-template={{range .status.loadBalancer.ingress}}{{print .ip "\n"}}{{end}}')
+$ curl $AMB_IP/foo
+foo
+```