Ingress with custom domain

Service Mesh OpenShift

- Thomas Jungbauer Thomas Jungbauer ( Lastmod: 2024-05-05 ) - 2 min read

Since Service Mesh 1.1, there is a better way to achieve the following. Especially the manual creation of the route is not required anymore. Check the following article to Enable Automatic Route Creation.

Often the question is how to get traffic into the Service Mesh when using a custom domains. Part 4 our our tutorials series OpenShift 4 and Service Mesh will use a dummy domain "hello-world.com" and explains the required settings which must be done.

Modify Gateway and VirtualService

Issue #3 explains how to get ingress traffic into the Service Mesh, by defining the Gateway and the VirtualService. We are currently using the default ingress route defined in the istio_system project.
But what if a custom domain shall be used?
In such case another route must be defined in the istio-system project and small configuration changes must be applied.

  1. First lets create a slightly modified Gateway.yaml:

    apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: ingress-gateway-exampleapp
spec:
  selector:
    istio: ingressgateway # use istio default controller
  servers:
  - port:
      number: 80
      name: http
      protocol: HTTP
    hosts:
    - "hello-world.com" (1)
    1add you custom domain here

    The only difference is at the hosts which was changed from '*' to 'hello-world.com'

  2. As second change, the VirtualService must be modified as well with the custom domain:

    VirtualService.yaml:

    apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: ingress-gateway-exampleapp
spec:
  hosts:
  - "hello-world.com" (1)
  gateways:
  - ingress-gateway-exampleapp
  http:
  - match:
    - uri:
        exact: /
    route:
    - destination:
        host: customer
        port:
          number: 8080
    1add you custom domain here

  3. Replace current objects in OpenShift:

    oc replace -f Gateway.yaml -n tutorial
oc replace -f VirtualService.yaml -n tutorial

  4. Create a new route under the project istio-system:

    apiVersion: route.openshift.io/v1
kind: Route
metadata:
  name: hello-world.com (1)
  namespace: istio-system (2)
spec:
  host: hello-world.com (3)
  to:
    kind: Service
    name: istio-ingressgateway (4)
  port:
    targetPort: 8080
    1add you custom domain here
    2the route must be created at istio-system
    3add you custom domain here
    4this is the service as it was created by the operator

OPTIONAL: Add custom domain to local hosts file

The custom domain hello-world.com must be resolvable somehow, pointing to the ingress router of OpenShift. This can be done, by adding the domain into the local hosts file (with all limitations this brings with it)

# Get IP address of:
oc -n istio-system get route istio-ingressgateway
echo "x.x.x.x hello-world.com" >> /etc/hosts

Create some example traffic

We will reuse the script of Issue #3 to simulate traffic. Since we changed the domain, the connection will go to hello-world.com

sh run-check.sh 1000 hello-world.com

This will send 1000 requests to our application:

# 0: customer => preference => recommendation v1 from 'f11b097f1dd0': 6626
# 1: customer => preference => recommendation v1 from 'f11b097f1dd0': 6627
# 2: customer => preference => recommendation v1 from 'f11b097f1dd0': 6628
# 3: customer => preference => recommendation v1 from 'f11b097f1dd0': 6629
# 4: customer => preference => recommendation v1 from 'f11b097f1dd0': 6630
# 5: customer => preference => recommendation v1 from 'f11b097f1dd0': 6631
...

See Also:

  • Single log out from Keycloak and OpenShift –

    The following 1-minute article is a follow-up to my previous article about how to use Keycloak as an authentication provider for OpenShift. In this article, I will show you how to configure Keycloak and OpenShift for Single Log Out (SLO). This means that when you log out from Keycloak, you will also be logged out from OpenShift automatically. This requires some additional configuration in Keycloak and OpenShift, but it is not too complicated.

  • Step by Step - Using Keycloak Authentication in OpenShift –

    I was recently asked about how to use Keycloak as an authentication provider for OpenShift. How to install Keycloak using the Operator and how to configure Keycloak and OpenShift so that users can log in to OpenShift using OpenID. I have to admit that the exact steps are not easy to find, so I decided to write a blog post about it, describing each step in detail. This time I will not use GitOps, but the OpenShift and Keycloak Web Console to show the steps, because before we put it into GitOps, we need to understand what is actually happening. This article tries to explain every step required so that a user can authenticate to OpenShift using Keycloak as an Identity Provider (IDP) and that Groups from Keycloak are imported into OpenShift. This article does not cover a production grade installation of Keycloak, but only a test installation, so you can see how it works. For production, you might want to consider a proper database (maybe external, but at least with a backup), high availability, etc.).

  • Using ApplicationSet with Matrix Generator and define individual Namespaces –

    During my day-to-day business, I am discussing the following setup with many customers: Configure App-of-Apps. Here I try to explain how I use an ApplicationSet that watches over a folder in Git and automatically adds a new Argo CD Application whenever a new folder is found. This works great, but there is a catch: The ApplicationSet uses the same Namespace default for all Applications. This is not always desired, especially when you have different teams working on different Applications. Recently I was asked by the customer if this can be fixed and if it is possible to define different Namespaces for each Application. The answer is yes, and I would like to show you how to do this.

  • Introducing AdminNetworkPolicies –

    Classic Kubernetes/OpenShift offer a feature called NetworkPolicy that allows users to control the traffic to and from their assigned Namespace. NetworkPolicies are designed to give project owners or tenants the ability to protect their own namespace. Sometimes, however, I worked with customers where the cluster administrators or a dedicated (network) team need to enforce these policies. Since the NetworkPolicy API is namespace-scoped, it is not possible to enforce policies across namespaces. The only solution was to create custom (project) admin and edit roles, and remove the ability of creating, modifying or deleting NetworkPolicy objects. Technically, this is possible and easily done. But shifts the whole network security to cluster administrators. Luckily, this is where AdminNetworkPolicy (ANP) and BaselineAdminNetworkPolicy (BANP) comes into play.

  • Using Kustomize to post render a Helm Chart –

    Lately I came across several issues where a given Helm Chart must be modified after it has been rendered by Argo CD. Argo CD does a helm template to render a Chart. Sometimes, especially when you work with Subcharts or when a specific setting is not yet supported by the Chart, you need to modify it later …​ you need to post-render the Chart. In this very short article, I would like to demonstrate this on a real-live example I had to do. I would like to inject annotations to a Route objects, so that the certificate can be injected. This is done by the cert-utils operator. For the post-rendering the Argo CD repo pod will be extended with a sidecar container, that is watching for the repos and patches them if required.

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