Installing Knative Serving using YAML files¶

This topic describes how to install Knative Serving by applying YAML files using the kubectl CLI.

Prerequisites¶

Before installation, you must meet the prerequisites. See Knative Prerequisites.

Install the Serving component¶

To install the serving component:

Install the required custom resources:

kubectl apply -f http://github.com/knative/serving/releases/download/v0.20.0/serving-crds.yaml

Install the core components of Knative Serving:
```
kubectl apply -f http://github.com/knative/serving/releases/download/v0.20.0/serving-core.yaml
```
Info

For information about the YAML files in the Knative Serving and Eventing releases, see Installation files.

Install a networking layer¶

The tabs below expand to show instructions for installing a networking layer. Follow the procedure for the networking layer of your choice:

Kourier (Choose this if you are not sure)

The following commands install Kourier and enable its Knative integration.

Install the Knative Kourier controller:

kubectl apply -f http://github.com/knative/net-kourier/releases/download/v0.20.0/kourier.yaml

To configure Knative Serving to use Kourier by default:

kubectl patch configmap/config-network \
  --namespace knative-serving \
  --type merge \
  --patch '{"data":{"ingress.class":"kourier.ingress.networking.knative.dev"}}'

Fetch the External IP or CNAME:
```
kubectl --namespace kourier-system get service kourier
```
Tip
Save this to use in the Configure DNS section.

Ambassador

The following commands install Ambassador and enable its Knative integration.

Create a namespace to install Ambassador in:
```
kubectl create namespace ambassador
```

Install Ambassador:

kubectl apply --namespace ambassador \
  -f https://getambassador.io/yaml/ambassador/ambassador-crds.yaml \
  -f https://getambassador.io/yaml/ambassador/ambassador-rbac.yaml \
  -f https://getambassador.io/yaml/ambassador/ambassador-service.yaml

Give Ambassador the required permissions:

kubectl patch clusterrolebinding ambassador -p '{"subjects":[{"kind": "ServiceAccount", "name": "ambassador", "namespace": "ambassador"}]}'

Enable Knative support in Ambassador:

kubectl set env --namespace ambassador  deployments/ambassador AMBASSADOR_KNATIVE_SUPPORT=true

To configure Knative Serving to use Ambassador by default:

kubectl patch configmap/config-network \
  --namespace knative-serving \
  --type merge \
  --patch '{"data":{"ingress.class":"ambassador.ingress.networking.knative.dev"}}'

Fetch the External IP or CNAME:
```
kubectl --namespace ambassador get service ambassador
```
Tip
Save this to use in the Configure DNS section.

Contour

The following commands install Contour and enable its Knative integration.

Install a properly configured Contour:

kubectl apply -f http://github.com/knative/net-contour/releases/download/v0.20.0/contour.yaml

Install the Knative Contour controller:

kubectl apply -f http://github.com/knative/net-contour/releases/download/v0.20.0/net-contour.yaml

To configure Knative Serving to use Contour by default:

kubectl patch configmap/config-network \
  --namespace knative-serving \
  --type merge \
  --patch '{"data":{"ingress.class":"contour.ingress.networking.knative.dev"}}'

Fetch the External IP or CNAME:
```
kubectl --namespace contour-external get service envoy
```
Tip
Save this to use in the Configure DNS section.

Gloo

For a detailed guide on Gloo integration, see Installing Gloo for Knative in the Gloo documentation.

The following commands install Gloo and enable its Knative integration.

Make sure glooctl is installed (version 1.3.x and higher recommended):
```
glooctl version
```
If it is not installed, you can install the latest version using:
```
curl -sL https://run.solo.io/gloo/install | sh
export PATH=$HOME/.gloo/bin:$PATH
```
Or following the Gloo CLI install instructions.

Install Gloo and the Knative integration:

glooctl install knative --install-knative=false

Fetch the External IP or CNAME:
```
glooctl proxy url --name knative-external-proxy
```
Tip
Save this to use in the Configure DNS section.

Istio

The following commands install Istio and enable its Knative integration.

Install a properly configured Istio (Advanced installation)

kubectl apply -f http://github.com/knative/net-istio/releases/download/v0.20.0/istio.yaml

Install the Knative Istio controller:

kubectl apply -f http://github.com/knative/net-istio/releases/download/v0.20.0/net-istio.yaml

Fetch the External IP or CNAME:
```
kubectl --namespace istio-system get service istio-ingressgateway
```
Tip
Save this to use in the Configure DNS section.

Kong

The following commands install Kong and enable its Knative integration.

Install Kong Ingress Controller:

kubectl apply -f https://raw.githubusercontent.com/Kong/kubernetes-ingress-controller/0.9.x/deploy/single/all-in-one-dbless.yaml

To configure Knative Serving to use Kong by default:

kubectl patch configmap/config-network \
  --namespace knative-serving \
  --type merge \
  --patch '{"data":{"ingress.class":"kong"}}'

Fetch the External IP or CNAME:
```
kubectl --namespace kong get service kong-proxy
```
Tip
Save this to use in the Configure DNS section.

Verify the installation¶

Monitor the Knative components until all of the components show a STATUS of Running or Completed:

kubectl get pods --namespace knative-serving

Configure DNS¶

You can configure DNS to prevent the need to run curl commands with a host header.

The tabs below expand to show instructions for configuring DNS. Follow the procedure for the DNS of your choice:

Magic DNS (xip.io)

We ship a simple Kubernetes Job called "default domain" that will (see caveats) configure Knative Serving to use xip.io as the default DNS suffix.

kubectl apply -f http://github.com/knative/serving/releases/download/v0.20.0/serving-default-domain.yaml

CAVEAT

This will only work if the cluster LoadBalancer service exposes an IPv4 address or hostname, so it will not work with IPv6 clusters or local setups like Minikube. For these, see "Real DNS" or "Temporary DNS".

Real DNS

To configure DNS for Knative, take the External IP or CNAME from setting up networking, and configure it with your DNS provider as follows:

If the networking layer produced an External IP address, then configure a wildcard A record for the domain:

# Here knative.example.com is the domain suffix for your cluster
*.knative.example.com == A 35.233.41.212

If the networking layer produced a CNAME, then configure a CNAME record for the domain:

# Here knative.example.com is the domain suffix for your cluster
*.knative.example.com == CNAME a317a278525d111e89f272a164fd35fb-1510370581.eu-central-1.elb.amazonaws.com

Once your DNS provider has been configured, direct Knative to use that domain:

# Replace knative.example.com with your domain suffix
kubectl patch configmap/config-domain \
  --namespace knative-serving \
  --type merge \
  --patch '{"data":{"knative.example.com":""}}'

Temporary DNS

Info

If you are using curl to access the sample applications, or your own Knative app, and are unable to use the "Magic DNS (xip.io)" or "Real DNS" methods, there is a temporary approach. This is useful for those who wish to evaluate Knative without altering their DNS configuration, as per the "Real DNS" method, or cannot use the "Magic DNS" method due to using, for example, minikube locally or IPv6 clusters.

To access your application using curl using this method:

After starting your application, get the URL of your application:

kubectl get ksvc

Verify the output

NAME            URL                                        LATESTCREATED         LATESTREADY           READY   REASON
helloworld-go   http://helloworld-go.default.example.com   helloworld-go-vqjlf   helloworld-go-vqjlf   True

Instruct curl to connect to the External IP or CNAME defined by the networking layer in section 3 above, and use the -H "Host:" command-line option to specify the Knative application's host name. For example, if the networking layer defines your External IP and port to be http://192.168.39.228:32198 and you wish to access the above helloworld-go application, use:
```
curl -H "Host: helloworld-go.default.example.com" http://192.168.39.228:32198
```
Verify the output
In the case of the provided helloworld-go sample application, the output should, using the default configuration, be:
```
Hello Go Sample v1!
```

Refer to the "Real DNS" method for a permanent solution.

Next steps¶

After installing Knative Serving:

Installing Knative Eventing using YAML files
To add optional enhancements to your installation, see Installing optional extensions.
To easily interact with Knative Services, install the kn CLI