Project: Contour (Orchestration & Management / Service Proxy)
File: fundamentals.md

The object was added to Kubernetes in version 1.1 to describe properties of a cluster-wide reverse HTTP proxy. Since that time, the Ingress API has remained relatively unchanged, and the need to express implementation-specific capabilities has inspired an . The goal of the HTTPProxy Custom Resource Definition (CRD) is to expand upon the functionality of the Ingress API to allow for a richer user experience as well addressing the limitations of the latter's use in multi tenant environments. Safely supports multi-team Kubernetes clusters, with the ability to limit which Namespaces may configure virtual hosts and TLS credentials. Enables including of routing configuration for a path or domain from another HTTPProxy, possibly in another Namespace. Accepts multiple services within a single route and load balances traffic across them. Natively allows defining service weighting and load balancing strategy without annotations. Validation of HTTPProxy objects at creation time and status reporting for post-creation validity. A minimal Ingress object might look like: ```yaml apiVersion: networking.k8s.io/v1 kind: Ingress metadata: name: basic spec: rules: host: foo-basic.bar.com http: paths: backend: service: name: s1 port: number: 80 ``` This Ingress object, named `basic`, will route incoming HTTP traffic with a `Host:` header for `foo-basic.bar.com` to a Service named `s1` on port `80`. Implementing similar behavior using an HTTPProxy looks like this: ```yaml apiVersion: projectcontour.io/v1 kind: HTTPProxy metadata: name: basic spec: virtualhost: fqdn: foo-basic.bar.com routes: conditions: prefix: / services: name: s1 port: 80 ``` Lines 1-5: As with all other Kubernetes objects, an HTTPProxy needs apiVersion, kind, and metadata fields. Lines 7-8: The presence of the `virtualhost` field indicates that this is a root HTTPProxy that is the top level entry point for this domain. As with all Kubernetes objects, you can use `kubectl` to create, list, describe, edit, and delete HTTPProxy CRDs. Creating an HTTPProxy: ```bash $ kubectl create -f basic.httpproxy.yaml httpproxy "basic" created ``` Listing HTTPProxies: ```bash $ kubectl get httpproxy NAME AGE basic 24s ``` Describing HTTPProxy: ```bash $ kubectl describe httpproxy basic Name: basic Namespace: default Labels: <none> API Version: projectcontour.io/v1 Kind: HTTPProxy Metadata: Cluster Name: Creation Timestamp: 2019-07-05T19:26:54Z Resource Version: 19373717 Self Link: /apis/projectcontour.io/v1/namespaces/default/httpproxy/basic UID: 6036a9d7-8089-11e8-ab00-f80f4182762e Spec: Routes: Conditions: Prefix: / Services: Name: s1 Port: 80 Virtualhost: Fqdn: foo-basic.bar.com Events: <none> ``` Deleting HTTPProxies: ```bash $ kubectl delete httpproxy basic httpproxy "basic" deleted ``` There are many misconfigurations that could cause an HTTPProxy or delegation to be

Contour will make its best effort to process even partially valid configuration and allow traffic to be served for the valid parts. To aid users in resolving any issues, Contour updates a `status` field in all HTTPProxy objects. If an HTTPProxy object is valid, it will have a status property that looks like this: ```yaml status: currentStatus: valid description: valid HTTPProxy ``` If the HTTPProxy is invalid, the `currentStatus` field will be `invalid` and the `description` field will provide a description of the issue. As an example, if an HTTPProxy object has specified a negative value for weighting, the HTTPProxy status will be: ```yaml status: currentStatus: invalid description: "route '/foo': service 'home': weight must be greater than or equal to zero" ``` Some examples of invalid configurations that Contour provides statuses for: Negative weight provided in the route definition. Invalid port number provided for service. Prefix in parent does not match route in delegated route. Root HTTPProxy created in a namespace other than the allowed root namespaces. A given Route of an HTTPProxy both delegates to another HTTPProxy and has a list of services. Orphaned route. Delegation chain produces a cycle. Root HTTPProxy does not specify fqdn. Multiple prefixes cannot be specified on the same set of route conditions. Multiple header conditions of type "exact match" with the same header key. Contradictory header conditions on a route, e.g. a "contains" and "notcontains" condition for the same header and value. Invalid configuration is ignored and will be not used in the ingress routing configuration. Envoy will respond with an error when HTTP request is received on route with invalid configuration on following cases: `502 Bad Gateway` response is sent when HTTPProxy has an include that refers to an HTTPProxy that does not exist. `503 Service Unavailable` response is sent when HTTPProxy refers to a service that does not exist. Following example has two routes: the first one is valid, the second one refers to a service that does not exist. ```yaml apiVersion: projectcontour.io/v1 kind: HTTPProxy metadata: name: multiple-routes-with-a-missing-service spec: virtualhost: fqdn: www.example.com routes: conditions: prefix: / services: name: valid-service port: 80 conditions: prefix: /subpage services: name: service-that-does-not-exist port: 80 ``` The `HTTPProxy` will have condition `Valid=false` with detailed error message: `Spec.Routes unresolved service reference: service "default/service-that-does-not-exist" not found`. Requests received for `http://www.example.com/` will be forwarded to `valid-service` but requests received for `http://www.example.com/subpage` will result in error `503 Service Unavailable` response from Envoy. The full HTTPProxy specification is described in detail in the . There are a number of working examples of HTTPProxy objects in the directory of the Contour Github repository.