Setting up Istio Role-Based Access Control

This task shows how to set up role-based access control (RBAC) for services in Istio mesh. You can read more about Istio RBAC from Istio RBAC concept page.

Before you begin

Set up Istio on auth-enabled Kubernetes by following the instructions in the quick start. Note that authentication should be enabled at step 5 in the installation steps.
Deploy the Bookinfo sample application.

> Note: The current Istio release may not have the up-to-date Istio RBAC samples. So before you continue, you need to copy the following configuration files from https://github.com/istio/istio/tree/master/samples/bookinfo/kube to “samples/bookinfo/kube” directory under where you installed Istio, and replace the original ones. The files include bookinfo-add-serviceaccount.yaml, istio-rbac-enable.yaml, istio-rbac-namespace.yaml, istio-rbac-productpage.yaml, istio-rbac-details-reviews.yaml, istio-rbac-ratings.yaml.

In this task, we will enable access control based on Service Accounts, which are cryptographically authenticated in the Istio mesh. In order to give different microservices different access privileges, we will create some service accounts and redeploy Bookinfo microservices running under them.
Run the following command to
- Create service account bookinfo-productpage, and redeploy the service productpage with the service account.
- Create service account bookinfo-reviews, and redeploy the services reviews (deployments reviews-v2 and reviews-v3) with the service account.
```
kubectl apply -f <(istioctl kube-inject -f samples/bookinfo/kube/bookinfo-add-serviceaccount.yaml)
```
You can expect to see the output similar to the following:
```
serviceaccount "bookinfo-productpage" created
deployment "productpage-v1" configured
serviceaccount "bookinfo-reviews" created
deployment "reviews-v2" configured
deployment "reviews-v3" configured
```
Note: if you are using a namespace other than default, use istioctl -n namespace ... to specify the namespace.

Point your browser at the Bookinfo productpage (http://$GATEWAY_URL/productpage). You should see:

“Book Details” section in the lower left part of the page, including type, pages, publisher, etc.
“Book Reviews” section in the lower right part of the page.

Enabling Istio RBAC

Run the following command to enable Istio RBAC for “default” namespace.

Note: if you are using a namespace other than default, edit the file samples/bookinfo/kube/istio-rbac-enable.yaml, and specify the namespace, say "your-namespace", in the match statement in rule spec "match: destination.namespace == "your-namespace".

kubectl apply -f samples/bookinfo/kube/istio-rbac-enable.yaml

It also defines “requestcontext”, which is an instance of the authorization template. “requestcontext” defines the input to the RBAC engine at runtime.

Point your browser at the Bookinfo productpage (http://$GATEWAY_URL/productpage). Now you should see "PERMISSION_DENIED:handler.rbac.istio-system:RBAC: permission denied." This is because Istio RBAC is “deny by default”, which means that you need to explicitly define access control policy to grant access to any service.

Note: There may be delay due to caching on browser and Istio proxy.

Namespace-level access control

Using Istio RBAC, you can easily setup namespace-level access control by specifying all (or a collection of) services in a namespace are accessible by services from another namespace.

In our Bookinfo sample, the “productpage”, “reviews”, “details”, “ratings” services are deployed in “default” namespace. The Istio components like “ingress” service are deployed in “istio-system” namespace. We can define a policy that any service in “default” namespace that has “app” label set to one of the values in [“productpage”, “details”, “reviews”, “ratings”] is accessible by services in the same namespace (i.e., “default” namespace) and services in “istio-system” namespace.

Run the following command to create a namespace-level access control policy.

kubectl apply -f samples/bookinfo/kube/istio-rbac-namespace.yaml

The policy does the following:

Creates a ServiceRole “service-viewer” which allows read access to any service in “default” namespace that has “app” label set to one of the values in [“productpage”, “details”, “reviews”, “ratings”]. Note that there is a “constraint” specifying that the services must have one of the listed “app” labels.
```
apiVersion: "config.istio.io/v1alpha2"
kind: ServiceRole
metadata:
  name: service-viewer
  namespace: default
spec:
  rules:
  - services: ["*"]
    methods: ["GET"]
    constraints:
    - key: "app"
      values: ["productpage", "details", "reviews", "ratings"]
```

Creates a ServiceRoleBinding that assign the “service-viewer” role to all services in “istio-system” and “default” namespaces.

apiVersion: "config.istio.io/v1alpha2"
kind: ServiceRoleBinding
metadata:
  name: bind-service-viewer
  namespace: default
spec:
  subjects:
  - properties:
      namespace: "istio-system"
  - properties:
      namespace: "default"
  roleRef:
    kind: ServiceRole
    name: "service-viewer"

You can expect to see the output similar to the following:

servicerole "service-viewer" created
servicerolebinding "bind-service-viewer" created

Now if you point your browser at Bookinfo productpage (http://$GATEWAY_URL/productpage). You should see “Bookinfo Sample” page, with “Book Details” section in the lower left part and “Book Reviews” section in the lower right part.

Note: There may be delay due to caching on browser and Istio proxy.

Cleanup namespace-level access control

Remove the following configuration before you proceed to the next task:

kubectl delete -f samples/bookinfo/kube/istio-rbac-namespace.yaml

Service-level access control

This task shows you how to set up service-level access control using Istio RBAC. Before you start, please make sure that:

You have enabled Istio RBAC.
You have removed namespace-level Istio RBAC policy.

Point your browser at the Bookinfo productpage (http://$GATEWAY_URL/productpage). You should see "PERMISSION_DENIED:handler.rbac.istio-system:RBAC: permission denied." We will incrementally add access to the services in Bookinfo sample.

Step 1. allowing access to “productpage” service

In this step, we will create a policy that allows external requests to view productpage service via Ingress.

Run the following command:

kubectl apply -f samples/bookinfo/kube/istio-rbac-productpage.yaml

The policy does the following:

Creates a ServiceRole “productpage-viewer” which allows read access to “productpage” service.

apiVersion: "config.istio.io/v1alpha2"
kind: ServiceRole
metadata:
  name: productpage-viewer
  namespace: default
spec:
  rules:
  - services: ["productpage"]
    methods: ["GET"]

Creates a ServiceRoleBinding “bind-productpager-viewer” which assigns “productpage-viewer” role to all users/services.

apiVersion: "config.istio.io/v1alpha2"
kind: ServiceRoleBinding
metadata:
  name: bind-productpager-viewer
  namespace: default
spec:
  subjects:
  - user: "*"
  roleRef:
    kind: ServiceRole
    name: "productpage-viewer"

Point your browser at the Bookinfo productpage (http://$GATEWAY_URL/productpage). Now you should see “Bookinfo Sample” page. But there are errors "Error fetching product details" and "Error fetching product reviews" on the page. These errors are expected because we have not granted “productpage” service to access “details” and “reviews” services. We will fix the errors in the following steps.

Note: There may be delay due to caching on browser and Istio proxy.

Step 2. allowing “productpage” service to access “details” and “reviews” services

We will create a policy to allow “productpage” service to read “details” and “reviews” services. Note that in the setup step, we created a service account “bookinfo-productpage” for “productpage” service. This “bookinfo-productpage” service account is the authenticated identify for “productpage” service.

Run the following command:

kubectl apply -f samples/bookinfo/kube/istio-rbac-details-reviews.yaml

The policy does the following:

Creates a ServiceRole “details-reviews-viewer” which allows read access to “details” and “reviews” services.

apiVersion: "config.istio.io/v1alpha2"
kind: ServiceRole
metadata:
  name: details-reviews-viewer
  namespace: default
spec:
  rules:
  - services: ["details", "reviews"]
    methods: ["GET"]

Creates a ServiceRoleBinding “bind-details-reviews” which assigns “details-reviews-viewer” role to service account “cluster.local/ns/default/sa/bookinfo-productpage” (representing the “productpage” service).

apiVersion: "config.istio.io/v1alpha2"
kind: ServiceRoleBinding
metadata:
  name: bind-details-reviews
  namespace: default
spec:
  subjects:
  - user: "cluster.local/ns/default/sa/bookinfo-productpage"
  roleRef:
    kind: ServiceRole
    name: "details-reviews-viewer"

Point your browser at the Bookinfo productpage (http://$GATEWAY_URL/productpage). Now you should see “Bookinfo Sample” page with “Book Details” on the lower left part, and “Book Reviews” on the lower right part. However, in “Book Reviews” section, there is an error "Ratings service currently unavailable". This is because “reviews” service does not have permission to access “ratings” service. To fix this issue, you need to grant “reviews” service read access to “ratings” service. We will show how to do that in the next step.

Note: There may be delay due to caching on browser and Istio proxy.

Step 3. allowing “reviews” service to access “ratings” service

We will create a policy to allow “reviews” service to read “ratings” service. Note that in the setup step, we created a service account “bookinfo-reviews” for “reviews” service. This “bookinfo-reviews” service account is the authenticated identify for “reviews” service.

Run the following command to create a policy that allows “reviews” service to read “ratings” service.

kubectl apply -f samples/bookinfo/kube/istio-rbac-ratings.yaml

The policy does the following:

Creates a ServiceRole “ratings-viewer” which allows read access to “ratings” service.

apiVersion: "config.istio.io/v1alpha2"
kind: ServiceRole
metadata:
  name: ratings-viewer
  namespace: default
spec:
  rules:
  - services: ["ratings"]
    methods: ["GET"]

Creates a ServiceRoleBinding “bind-ratings” which assigns “ratings-viewer” role to service account “cluster.local/ns/default/sa/bookinfo-reviews”, which represents the “reviews” services.

apiVersion: "config.istio.io/v1alpha2"
kind: ServiceRoleBinding
metadata:
  name: bind-ratings
  namespace: default
spec:
  subjects:
  - user: "cluster.local/ns/default/sa/bookinfo-reviews"
  roleRef:
    kind: ServiceRole
    name: "ratings-viewer"

Point your browser at the Bookinfo productpage (http://$GATEWAY_URL/productpage). Now you should see the “black” and “red” ratings in “Book Reviews” section.

Note: There may be delay due to caching on browser and Istio proxy.

If you would like to only see “red” ratings in “Book Reviews” section, you can do that by specifying that only “reviews” service at version “v3” can access “ratings” service.

apiVersion: "config.istio.io/v1alpha2"
kind: ServiceRoleBinding
metadata:
  name: bind-ratings
  namespace: default
spec:
  subjects:
  - user: "cluster.local/ns/default/sa/bookinfo-reviews"
    properties:
      version: "v3"
  roleRef:
    kind: ServiceRole
    name: "ratings-viewer"

Cleanup

Remove Istio RBAC policy configuration:

kubectl delete -f samples/bookinfo/kube/istio-rbac-ratings.yaml
kubectl delete -f samples/bookinfo/kube/istio-rbac-details-reviews.yaml
kubectl delete -f samples/bookinfo/kube/istio-rbac-productpage.yaml

Alternatively, you can delete all ServiceRole and ServiceRoleBinding objects by running the following commands:

kubectl delete servicerole --all
kubectl delete servicerolebinding --all

Disable Istio RBAC:

kubectl delete -f samples/bookinfo/kube/istio-rbac-enable.yaml

What’s next

Learn more about Istio RBAC.