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Ingress to Gateway

Ingress2gateway helps translate Ingress and provider-specific resources (CRDs) to Gateway API resources. Ingress2gateway is managed by the Gateway API SIG-Network subproject.

Scope

Ingress2gateway is primarily focused on translating Ingress and provider-specific resources(CRDs) to Gateway API resources. Widely used provider-specific annotations and/or CRDs may still not be supported. Please refer to supported providers for the current supported providers and their documentation. Contributions for provider-specific annotations and/or CRDs support are mostly welcomed as long as they can be translated to Gateway API directly.

Note: Ingress2gateway is not intended to copy annotations from Ingress to Gateway API.

Supported providers

If your provider, or a specific feature, is not currently supported, please open an issue and describe your use case.

To contribute a new provider support - please read PROVIDER.md.

Installation

Via go install

If you have a Go development environment locally, you can install ingress2gateway with go install github.com/kubernetes-sigs/ingress2gateway@v0.3.0

This will put ingress2gateway binary in $(go env GOPATH)/bin

Alternatively, you can download the binary at the releases page

On macOS and linux via Homebrew

Make sure Homebrew is installed on your system.

brew install ingress2gateway

Build from Source

Ensure that your system meets the following requirements:
- Install Git: Make sure Git is installed on your system to clone the project repository.
- Install Go: Make sure the go language is installed on your system. You can download it from the official website (https://golang.org/dl/) and follow the installation instructions.

Clone the project repository

git clone https://github.com/kubernetes-sigs/ingress2gateway.git && cd ingress2gateway

Build the project
```
make build
```

Usage

Ingress2gateway reads Ingress resources and/or provider-specifc CRDs from a Kubernetes cluster or a file. It will output the equivalent Gateway API resources in a YAML/JSON format to stdout. To run ingress2gateway with default options simply run:

./ingress2gateway print

The above command will:

Read your Kube config file to extract the cluster credentials and the current active namespace.
Search for ingresses and provider-specific resources in that namespace.
Convert them to Gateway-API resources (Currently only Gateways and HTTPRoutes).

Options

`print` command

Flag	Default Value	Required	Description
all-namespaces	False	No	If present, list the requested object(s) across all namespaces. Namespace in the current context is ignored even if specified with --namespace.
input-file		No	Path to the manifest file. When set, the tool will read ingresses from the file instead of reading from the cluster. Supported files are yaml and json.
namespace		No	If present, the namespace scope for the invocation.
openapi3-backend		No	Provider-specific: openapi3. The name of the backend service to use in the HTTPRoutes.
openapi3-gateway-class-name		No	Provider-specific: openapi3. The name of the gateway class to use in the Gateways.
openapi3-gateway-tls-secret		No	Provider-specific: openapi3. The name of the secret for the TLS certificate references in the Gateways.
output	yaml	No	The output format, either yaml or json.
providers	all supported providers	Yes	Comma-separated list of providers.
kubeconfig		No	The kubeconfig file to use when talking to the cluster. If the flag is not set, a set of standard locations can be searched for an existing kubeconfig file.

Conversion of Ingress resources to Gateway API

Processing Order and Conflicts

Ingress resources will be processed with a defined order to ensure deterministic generated Gateway API configuration. This should also determine precedence order of Ingress resources and routes in case of conflicts.

Ingress resources with the oldest creation timestamp will be sorted first and therefore given precedence. If creation timestamps are equal, then sorting will be done based on the namespace/name of the resources. If an Ingress rule conflicts with another (e.g. same path match but different backends) an error will be reported for the one that sorted later.

Since the Ingress v1 spec does not itself have a conflict resolution guide, we have adopted this one. These rules are similar to the Gateway API conflict resolution guidelines.

Ingress resource fields to Gateway API fields

Given a set of Ingress resources, ingress2gateway will generate a Gateway with various HTTP and HTTPS Listeners as well as HTTPRoutes that should represent equivalent routing rules.

Ingress Field	Gateway API configuration
`ingressClassName`	If configured on an Ingress resource, this value will be used as the `gatewayClassName` set on the corresponding generated Gateway. `kubernetes.io/ingress.class` annotation has the same behavior.
`defaultBackend`	If present, this configuration will generate a Gateway Listener with no `hostname` specified as well as a catchall HTTPRoute that references this listener. The backend specified here will be translated to a HTTPRoute `rules[].backendRefs[]` element.
`tls[].hosts`	Each host in an IngressTLS will result in a HTTPS Listener on the generated Gateway with the following: `listeners[].hostname` = host as described, `listeners[].port` = `443`, `listeners[].protocol` = `HTTPS`, `listeners[].tls.mode` = `Terminate`
`tls[].secretName`	The secret specified here will be referenced in the Gateway HTTPS Listeners mentioned above with the field `listeners[].tls.certificateRefs`. Each Listener for each host in an IngressTLS will get this secret.
`rules[].host`	If non-empty, each distinct value for this field in the provided Ingress resources will result in a separate Gateway HTTP Listener with matching `listeners[].hostname`. `listeners[].port` will be set to `80` and `listeners[].protocol` set to `HTTPS`. In addition, Ingress rules with the same hostname will generate HTTPRoute rules in a HTTPRoute with `hostnames` containing it as the single element. If empty, similar to the `defaultBackend`, a Gateway Listener with no hostname configuration will be generated (if it doesn't exist) and routing rules will be generated in a catchall HTTPRoute.
`rules[].http.paths[].path`	This field translates to a HTTPRoute `rules[].matches[].path.value` configuration.
`rules[].http.paths[].pathType`	This field translates to a HTTPRoute `rules[].matches[].path.type` configuration. Ingress `Exact` = HTTPRoute `Exact` match. Ingress `Prefix` = HTTPRoute `PathPrefix` match.
`rules[].http.paths[].backend`	The backend specified here will be translated to a HTTPRoute `rules[].backendRefs[]` element.

Get Involved

This project will be discussed in the same Slack channel and community meetings as the rest of the Gateway API subproject. For more information, refer to the Gateway API Community page.

Code of conduct

Participation in the Kubernetes community is governed by the Kubernetes Code of Conduct.