Configuring custom domains
- Prerequisites
- Procedure

Configuring custom domains

Feature Availability: beta since Knative v0.24

beta features are well-tested and enabling them is considered safe. Support for the overall feature will not be dropped, though details may change in incompatible ways.

Each Knative Service is automatically assigned a default domain name when it is created. However, you can map any custom domain name that you own to a Knative Service, by using domain mapping.

You can create a DomainMapping object to map a single, non-wildcard domain to a specific Knative Service.

For example, if you own the domain name example.org, and you configure the domain DNS to reference your Knative cluster, you can use DomainMapping to serve a Knative Service at this domain.

Note

If you create a domain mapping to map to a private Knative Service, the private Knative Service is accessible from public internet with the custom domain of the domain mapping.

Tip

This topic instructs how to customize the domain of each service, regardless of the default domain. If you want to customize the domain template to assign the default domain name, see Changing the default domain.

Prerequisites

You must have access to a Kubernetes cluster, with Knative Serving and an Ingress implementation installed. For more information, see the Serving Installation documentation.
You must have the domain mapping feature enabled on your cluster.
You must have access to a Knative service that you can map a domain to.
You must own or have access to a domain name to map, and be able to change the domain DNS to point to your Knative cluster by using the tools provided by your domain registrar.

Procedure

To create a DomainMapping, you must first have a ClusterDomainClaim. This ClusterDomainClaim delegates the domain name to the namespace you want to create the DomainMapping in, which enables DomainMappings in that namespace to use the domain name.

Create a ClusterDomainClaim manually or configure automatic creation of ClusterDomainClaims:
- To create a ClusterDomainClaim manually:
  1. Create a YAML file using the following template:
```
apiVersion: networking.internal.knative.dev/v1alpha1
kind: ClusterDomainClaim
metadata:
  name: <domain-name>
spec:
  namespace: <namespace>
```
  2. Apply the YAML file by running the command:
```
kubectl apply -f <filename>.yaml
```
    Where <filename> is the name of the file you created in the previous step.
- To create ClusterDomainClaims automatically: set the autocreate-cluster-domain-claims property to true in the config-network ConfigMap in the knative-serving namespace. This allows any user, in any namespace, to map any domain name, including ones in other namespaces or for domain names that they do not own.
Create a DomainMapping object:

YAMLkn
1. Create a YAML file using the following template:
```
apiVersion: serving.knative.dev/v1beta1
kind: DomainMapping
metadata:
  name: <domain-name>
  namespace: <namespace>
spec:
  ref:
    name: <service-name>
    kind: Service
    apiVersion: serving.knative.dev/v1
  tls:
    secretName: <cert-secret>
```
  Where:
  - <domain-name> is the domain name that you want to map a Service to.
  - <namespace> is the namespace that contains both the DomainMapping and Service objects.
  - <service-name> is the name of the Service that is mapped to the domain.
  - <cert-secret> is the name of a Secret that holds the server certificate for TLS communication. If this optional tls: section is provided, the protocol is switched from HTTP to HTTPS.
  Tip
  
  You can also map to other targets as long as they conform to the Addressable contract and their resolved URL is of the form <name>.<namespace>.<clusterdomain>, where <name> and <namespace> are the name and namespace of a Kubernetes Service, and <clusterdomain>is the cluster domain. Examples of objects that conform to this contract include Knative Services, Routes, and Kubernetes Services.
2. Apply the YAML file by running the command:
```
kubectl apply -f <filename>.yaml
```
  Where <filename> is the name of the file you created in the previous step.
Run the command:
```
kn domain create <domain-name> --ref <target> --tls <tls-secret> --namespace <namespace>
```
Where:
- <domain-name> is the domain name that you want to map a Service or Route to.
- <target> is the name of the Service or Route that is mapped to the domain. You can use the prefix ksvc: or kroute: to specify whether to map the domain to a Knative Service or Route. If no prefix is given, ksvc: is assumed. Additionally, you can use a :namespace suffix to point to a Service or Route in a different namespace. Examples:
  - mysvc maps to a Service mysvc in the same namespace as this mapping.
  - kroute:myroute:othernamespace maps to a Route myroute in namespace othernamespace.
- <tls-secret> is optional and if provided enables the TLS protocol. The value specifies the secret that holds the server certificate.
- <namespace> is the namespace where you want to create the DomainMapping. By default the DomainMapping is created in the current namespace.
Note

In addition to creating DomainMappings, you can use the kn domain command to list, describe, update, and delete existing DomainMappings. For more information about the command, run kn domain --help.
Point the domain name to the IP address of your Knative cluster. Details of this step differ depending on your domain registrar.