Istio with Pomerium

Istio provides application-aware networking via a service mesh and control plane. When configured with the Pomerium Ingress Controller for kubernetes, this enables authorization (authZ) and authentication (authN) of east-west traffic in your internal network bringing you closer to complete zero trust.

In this guide, we'll demonstrate how to configure Pomerium and Istio in a Kubernetes environment to provide mutual authentication at both the transport and application layer. We'll demonstrate first with a simple test service (Nginx), and then use Grafana to illustrate how the final service can use the same authentication data for user association.

Before You Begin

• You will need a Kubernetes environment with Istio installed. Refer to their Getting Started guide for more information.
• This configuration uses the Pomerium Ingress Controller for north-south traffic. This guide uses our Helm chart as detailed in Install Pomerium using Helm. We'll cover the values needed to configure the controller with an Istio service mesh, but you can refer to the documentation for a complete overview of the controller spec.

How it Works

In our Mutual Authentication section on Sidecars, we detail how a single service can offload authN and authz to a sidecar service. In a service mesh, each service in an internal network is deployed with a sidecar, and the controller configures them to provide mutual authentication with each other:

tip

This is a simplified model that doesn't describe the additional traffic for authorization and authentication.

See the Legend on our Mutual Authentication page for details on our graphing style.

Configure Pomerium for Istio

Follow Install Pomerium using Helm to set up the Pomerium Ingress Controller and Services, with the following adjustments.

1. Apply the appropriate label for Istio injection into your Pomerium namespace:

   kubectl label namespace pomerium istio-injection=enabled

2. Update your pomerium-values.yaml file, making note of the changes for integration with Istio:

   pomerium-values.yaml

   authenticate:
     idp:
       provider: "google"
       clientID: YOUR_CLIENT_ID
       clientSecret: YOUR_SECRET
       serviceAccount: YOUR_SERVICE_ACCOUNT
   
   proxy:
     deployment:
       podAnnotations:
         traffic.sidecar.istio.io/excludeInboundPorts: "80,443" # allow external connections to terminate directly on the Pomerium proxy rather than the sidecar
   
   config:
     rootDomain: localhost.pomerium.io
     generateTLS: false # disable certificate generation since we offload TLS to the mesh
     insecure: true # disable TLS on internal Pomerium services
   
   ingress:
     enabled: false # disable the default ingress resource since we are using our ingress controller
   
   ingressController:
     enabled: true # enable the Pomerium Ingress Controller
   
   redis:
     tls:
       enabled: false # TLS is handled by istio
     enabled: true
   
   service:
     authorize:
       headless: false # send traffic to the Pomerium Authorize through the Istio service rather than to individual pods
     databroker:
       headless: false # send traffic to the Pomerium Databroker through the Istio service rather than to individual pods

3. When defining a test service, you should now see two containers for the service pod:

   kubectl get pods
   NAME                                           READY   STATUS    RESTARTS   AGE
   ...
   nginx-6955473668-cxprp                         2/2     Running   0          19s

   This indicates that Istio has configured a sidecar container to handle traffic to and from the service.

Istio CRDs

Now that Pomerium is installed in the cluster, we can define authentication and authorization rules for Istio, which will validate traffic to our example service as coming from the Pomerium Proxy service, through an authorized route, and with an authenticated user token.

1. Adjust the following example nginx-istio-policy.yaml file to match your Kubernetes environment and domain names:

   nginx-istio-policy.yaml

   apiVersion: security.istio.io/v1beta1
   kind: RequestAuthentication
   metadata:
     name: nginx-require-pomerium-jwt
   spec:
     selector:
       matchLabels:
         app.kubernetes.io/name: nginx # This matches the label applied to our test service
     jwtRules:
     - issuer: "authenticate.localhost.pomerium.io" # Adjust to match your Authenticate service URL
       audiences:
         - hello.localhost.pomerium.io # This should match the value of spec.host in the services Ingress
       fromHeaders:
         - name: "X-Pomerium-Jwt-Assertion"
       jwksUri: https://authenticate.localhost.pomerium.io/.well-known/pomerium/jwks.json # Adjust to match your Authenticate service URL.
       # The jwksUri key above is the preferred method of retrieving the signing key, and should be used in production. See
       # See https://istio.io/latest/docs/reference/config/security/jwt/#JWTRule
       #
       #If the Authenticate service is using a localhost or other domain that's not a FQDN. You can instead provide the content from that path using the jwks key:
       #jwks: |
       #  {"keys":[{"use":"sig","kty":"EC","kid":"e1c5d20b9cf771de0bd6038ee5b5fe831f771d3715b72c2db921611ffca7242f","crv":"P-256","alg":"ES256","x":"j8I1I7eb0Imr2pvxRk13cK9ZjAA3VPrdUIHkAslX2e0","y":"jfWNKJkq3b5hrTz2JsrXCcvgJCPP7QSFgX1ZT9wapIQ"}]}
   ---
   apiVersion: security.istio.io/v1beta1
   kind: AuthorizationPolicy
   metadata:
     name: nginx-require-pomerium-jwt
   spec:
     selector:
       matchLabels:
         app.kubernetes.io/name: nginx # This matches the label applied to our test service
     action: ALLOW
     rules:
     - when:
       - key: request.auth.claims[aud]
         values: ["hello.localhost.pomerium.io"] # This should match the value of spec.host in the service's Ingress

   This file defines two Custom Resources. The first is a RequestAuthentication, and it specifies:

   • For objects with the app.kubernetes.io/name label matching nginx, Istio will check that:
     • the request includes the header X-Pomerium-Jwt-Assertion, which provides a JWT,
     • and that JWT is issued by the Pomerium Authenticate service,
     • and the JWT is signed by the signing key provided by the Authenticate service.

   If the JWT is found and validated, then the content within can be checked against the AuthorizationPolicy below. If the JWT is provided but not validated, it will not pass RequestAuthentication. If the JWT is not provided, the request will automatically fail any AuthorizationPolicy.

   The second resource is an AuthorizationPolicy, and it species:

   • For objects with the app.kubernetes.io/name label matching nginx, only allow requests:
     • if the request includes a JWT (already validated by RequestAuthentication) with the audience key aud,
     • and the value of the aud key matches our known route, hello.localhost.pomerium.io.

   In other words, RequestAuthentication confirms that the incoming traffic to the sidecar has a signed and valid JWT, which confirms that the user has been authenticated and is authorized to access this service. The AuthorizationPolicy confirms that the traffic originated from a valid Pomerium route. The latter is especially important in Pomerium Enterprise, where a manager of a separate Namespace could create a second route to a service normally routed and managed in your namespace.

2. Apply the new resources with kubectl:

   kubectl apply -f authorization-policy.yaml

3. Now when you go to hello.localhost.pomerium.io in the browser, you should see RBAC: access denied. This confirms that the policy is in place and denying our request. To allow the traffic, add the pass_identity_headers annotation to example-ingress.yaml:

   apiVersion: networking.k8s.io/v1
   kind: Ingress
   metadata:
     name: hello
     annotations:
       kubernetes.io/ingress.class: pomerium
       cert-manager.io/issuer: pomerium-issuer
       ingress.pomerium.io/pass_identity_headers: "true"
       ingress.pomerium.io/policy: '[{"allow":{"and":[{"domain":{"is":"example.com"}}]}}]'
   ...

4. After applying the update with kubectl apply -f example-ingress.yaml, you should now be able to access the test service in the browser.

Grafana

To demonstrate complete authorization validation through to the upstream service we'll use Grafana, as it's easy to configure to accept user authN from JWTs.

1. Add the Grafana repository to Helm:

   helm repo add grafana https://grafana.github.io/helm-charts

2. Create a grafana-values.yaml file and add the annotations for the Pomerium Ingress Controller:

   grafana-values.yaml

   ingress:
     enabled: true
     annotations:
       # Specify the certificate issuer for your namespace or cluster. For example:
       # cert-manager.io/issuer: pomerium-issuer
       kubernetes.io/ingress.class: pomerium
       ingress.pomerium.io/pass_identity_headers: "true"
       ingress.pomerium.io/policy: |
         - allow:
             or:
               - domain:
                   is: example.com
     hosts:
       - "grafana.localhost.pomerium.io"
     tls:
     - hosts:
       - grafana.localhost.pomerium.io
       secretName: grafana.localhost.pomerium.io-tls
   persistence:
     type: pvc
     enabled: false
     # storageClassName: default
     accessModes:
       - ReadWriteOnce
     size: 10Gi
     # annotations: {}
     finalizers:
       - kubernetes.io/pvc-protection

   tip

   Persistence is required to retain user data. Review the Grafana Helm chart configuration options to set the values for your environment.

3. Install Grafana to the cluster:

   helm upgrade --install grafana grafana/grafana --values grafana-values.yaml

4. Follow the instructions in the terminal output to log in as the admin user. Follow the Add Users to Grafana section of our Grafana guide to add a user that can be identified by the Pomerium JWT.

1. To the same file, add the following values to the grafana.ini section.

   grafana.ini.yaml

   grafana.ini:
     auth:
       disable_login_form: true
     auth.jwt:
       enabled: true
       header_name: X-Pomerium-Jwt-Assertion
       email_claim: email
       jwk_set_url: https://authenticate.localhost.pomerium.io/.well-known/pomerium/jwks.json

   This tells Grafana to use the email address provided in the X-Pomerium-Jwt-Assertion JWT and associate it with the matching Grafana user. It also disabled Grafana's login form. See Grafana's JWT authentication documentation for more configuration options.

2. Upgrade Grafana with the new configuration options:

   helm upgrade --install grafana grafana/grafana --values grafana-values.yaml

3. Now when you visit the Grafana route, you should be signed in as the user matching your Pomerium claim. To finalize the installation, create a new grafana-istio-policy.yaml file. Adjust the matchers and host values for Grafana, and enable forwardOriginalToken:

   apiVersion: security.istio.io/v1beta1
   kind: RequestAuthentication
   metadata:
     name: grafana-require-pomerium-jwt
   spec:
     selector:
       matchLabels:
         app.kubernetes.io/name: grafana # This matches the label applied to our test service
     jwtRules:
     - issuer: "authenticate.localhost.pomerium.io" # Adjust to match your Authenticate service URL
       audiences:
         - grafana.localhost.pomerium.io # This should match the value of spec.host in the services Ingress
       fromHeaders:
         - name: "X-Pomerium-Jwt-Assertion"
       forwardOriginalToken: true
       jwksUri: https://authenticate.localhost.pomerium.io/.well-known/pomerium/jwks.json # Adjust to match your Authenticate service URL.
       # The jwksUri key above is the preferred method of retrieving the signing key, and should be used in production.
       # See https://istio.io/latest/docs/reference/config/security/jwt/#JWTRule
       #
       #If the Authenticate service is using a localhost or other domain that's not a FQDN. You can instead provide the content from that path using the jwks key:
       #jwks: |
       #  {"keys":[{"use":"sig","kty":"EC","kid":"e1c5d20b9cf771de0bd6038ee5b5fe831f771d3715b72c2db921611ffca7242f","crv":"P-256","alg":"ES256","x":"j8I1I7eb0Imr2pvxRk13cK9ZjAA3VPrdUIHkAslX2e0","y":"jfWNKJkq3b5hrTz2JsrXCcvgJCPP7QSFgX1ZT9wapIQ"}]}
   ---
   apiVersion: security.istio.io/v1beta1
   kind: AuthorizationPolicy
   metadata:
     name: grafana-require-pomerium-jwt
   spec:
     selector:
       matchLabels:
         app.kubernetes.io/name: grafana # This matches the label applied to our test service
     action: ALLOW
     rules:
     - when:
       - key: request.auth.claims[aud]
         values: ["grafana.localhost.pomerium.io"] # This should match the value of spec.host in the service's Ingress

   Apply the policies with kubectl apply -f to complete the configuration.