Expose the Istio Ingress gateway via DNS¶

The following procedures are platform specific and work with a "standard classic" Kubernetes Cluster provided by the IBM Cloud Kubernetes Service (IKS) on the IBM Cloud.

If you are using a VPC based or a free ("Lite") Kubernetes Cluster on the IBM Cloud or another Cloud provider or something like Minikube, the following sections will not work!

When you install Istio on a Kubernetes Cluster on IBM Cloud, the Istio Ingress is created with a Kubernetes service of type LoadBalancer -- this is called a Network Load Balancer or NLB on IBM Cloud. A "floating" IP address is assigned to it through which it can be reached on the public Internet.

In this section we will assign a subdomain DNS entry for this IP address so that the Istio Ingress can be accessed using a URL.

Automated setup¶

Step 1: Ensure you exported the `$MYCLUSTER` variable¶

echo $MYCLUSTER

If this isn`t the case run, following commands:

Copy your cluster name from the output

ibmcloud ks cluster ls

Export the $MYCLUSTER variable

export MYCLUSTER=your_pre_provisioned_clustername

Step 2: Execute following script¶

  cd $ROOT_FOLDER
  bash IKS/istio-setup-ingress-gateway.sh

Example output:

...
OK
NLB hostname was created as harald-uebele-k8s-fra05-***-0001.us-south.containers.appdomain.cloud
------------------------------------------------------------------------
Ingress-URL: harald-uebele-k8s-fra05-***-0001.us-south.containers.appdomain.cloud
Cluster Name: harald-uebele-k8s-fra05
...

Step 3: Create a `$INGRESSURL` variable for later usage¶

Insert your YOUR_INGRESSURL value.

export INGRESSURL=YOUR_INGRESSURL
echo $INGRESSURL

FYI: Manual setup¶

The following steps show the manual steps of the automated setup. This is just for your information, you don't need to run them!

Step 1: Get public IP¶

When we install Istio on our pre-provisioned Kubernetes Clusters on IBM Cloud, the Istio Ingress is created with a Kubernetes service of type LoadBalancer and is assigned a "floating" IP address through which it can be reached on the public Internet. You can determine this address with the following command:

cd $ROOT_FOLDER/IKS
kubectl get svc -n istio-system | grep istio-ingressgateway

Output for example:

istio-ingressgateway   LoadBalancer  172.21.213.52  149.***.131.***   15020:31754/TCP,...

Step 2: Save public IP address¶

Our Ingress gateway is in fact of type LoadBalancer, the second IP address of the example 149.***.131.*** is the external (public) IP address. We need this public IP address in the next command.

export INGRESSGATEWAYIP=149.***.131.***

Step 3: Create a DNS subdomain¶

To create a DNS subdomain -- a URL -- for the Ingress gateway use the following command:

echo $MYCLUSTER
ibmcloud ks nlb-dns create classic --cluster $MYCLUSTER --ip $INGRESSGATEWAYIP

The new subdomain will have the form [cluster name]-[globally unique hash]-[sequence].[region].containers.appdomain.cloud. The output should look like this:

OK
NLB hostname was created as harald-uebele-k8s-fra05-********************-0001.eu-de.containers.appdomain.cloud

Step 4: Save DNS subdomain as $INGRESSURL¶

This will be the URL we will use later to access Keycloak and our sample application. Copy the URL and paste it into an environment variable:

export INGRESSURL=harald-uebele-k8s-fra05-********************-0001.eu-de.containers.appdomain.cloud