Authentication JWT

Service Mesh OpenShift

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

Welcome to tutorial 10 of OpenShift 4 and Service Mesh, where we will discuss authentication with JWT. JSON Web Token (JWT) is an open standard that allows to transmit information between two parties securely as a JSON object. It is an authentication token, which is verified and signed and therefore trusted. The signing can be achieved by using a secret or a public/private key pair.

Service Mesh can be used to configure a policy which enables JWT for your services.

Preparation

Be sure that you have at least the Gateway and VirtualService configured:

oc get istio-io -n tutorial

Which should return the following:

NAME                                                     AGE
gateway.networking.istio.io/ingress-gateway-exampleapp   45h

NAME                                                 HOST             AGE
destinationrule.networking.istio.io/recommendation   recommendation   29h

NAME                                                            GATEWAYS                       HOSTS   AGE
virtualservice.networking.istio.io/ingress-gateway-exampleapp   [ingress-gateway-exampleapp]   [*]     45h

Run some texample traffic, to be sure that our application is still working as expected

export GATEWAY_URL=$(oc -n istio-system get route istio-ingressgateway -o jsonpath='{.spec.host}')
sh ~/run.sh 1000 $GATEWAY_URL
# 0: customer => preference => recommendation v2 from '3cbba7a9cde5': 31622
# 1: customer => preference => recommendation v1 from 'f11b097f1dd0': 33056
# 2: customer => preference => recommendation v2 from '3cbba7a9cde5': 31623
# 3: customer => preference => recommendation v1 from 'f11b097f1dd0': 33057
# 4: customer => preference => recommendation v2 from '3cbba7a9cde5': 31624
# 5: customer => preference => recommendation v1 from 'f11b097f1dd0': 33058

Enabling End-User Authentication

To test this feature we will need a valid token (JWT). More details can be found at the Istio example

All we need to create a Policy object

apiVersion: "authentication.istio.io/v1alpha1"
kind: "Policy"
metadata:
  name: "jwt-example"
spec:
  targets:
  - name: customer
  origins:
  - jwt:
      issuer: "testing@secure.istio.io"
      jwksUri: "https://raw.githubusercontent.com/istio/istio/release-1.2/security/tools/jwt/samples/jwks.json" (1)
  principalBinding: USE_ORIGIN
1Path to test a public key

After a few seconds the requests will fail with an "authentication failed" error:

sh ~/run.sh 1000 $GATEWAY_URL
# 0: Origin authentication failed.
# 1: Origin authentication failed.
# 2: Origin authentication failed.
# 3: Origin authentication failed.
# 4: Origin authentication failed.
# 5: Origin authentication failed.

In Kiali we see a 100% failure rate.

Kiali JWT
Figure 1. Kiali: failing because of authentication error.

To be able to connect to our application we first need to fetch a valid token and put this into the header while sending curl.

export GATEWAY_URL=$(oc -n istio-system get route istio-ingressgateway -o jsonpath='{.spec.host}')
export TOKEN=$(curl https://raw.githubusercontent.com/istio/istio/release-1.1/security/tools/jwt/samples/demo.jwt -s)

for x in $(seq 1 1000);
  do curl --header "Authorization: Bearer $TOKEN" $GATEWAY_URL -s;
done

In Kiali the traffic is now working again and authenticated.

Kiali JWT2
Figure 2. Kiali: Traffic authenticated.

Clean Up

Remove the policy again, to be ready for the next tutorial.

oc delete policy jwt-example -n tutorial

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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