HTTP Traffic

HTTP Traffic

This task shows you how to set up Istio authorization policy of ALLOW action for HTTP traffic in an Istio mesh.

Before you begin

Before you begin this task, do the following:

Read the Istio authorization concepts.
Follow the Istio installation guide to install Istio with mutual TLS enabled.
Deploy the Bookinfo sample application.

After deploying the Bookinfo application, go to the Bookinfo product page at http://$GATEWAY_URL/productpage. On the product page, you can see the following sections:

Book Details on the lower left side, which includes: book type, number of pages, publisher, etc.
Book Reviews on the lower right of the page.

When you refresh the page, the app shows different versions of reviews in the product page. The app presents the reviews in a round robin style: red stars, black stars, or no stars.

If you don’t see the expected output in the browser as you follow the task, retry in a few more seconds because some delay is possible due to caching and other propagation overhead.

This task requires mutual TLS enabled because the following examples use principal and namespace in the policies.

Configure access control for workloads using HTTP traffic

Using Istio, you can easily setup access control for workloads in your mesh. This task shows you how to set up access control using Istio authorization. First, you configure a simple allow-nothing policy that rejects all requests to the workload, and then grant more access to the workload gradually and incrementally.

Run the following command to create a allow-nothing policy in the default namespace. The policy doesn’t have a selector field, which applies the policy to every workload in the default namespace. The spec: field of the policy has the empty value {}. That value means that no traffic is permitted, effectively denying all requests.
```
$ kubectl apply -f - <<EOF
apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: allow-nothing
  namespace: default
spec:
  {}
EOF
```
Point your browser at the Bookinfo productpage (http://$GATEWAY_URL/productpage). You should see "RBAC: access denied". The error shows that the configured deny-all policy is working as intended, and Istio doesn’t have any rules that allow any access to workloads in the mesh.
Run the following command to create a productpage-viewer policy to allow access with GET method to the productpage workload. The policy does not set the from field in the rules which means all sources are allowed, effectively allowing all users and workloads:
```
$ kubectl apply -f - <<EOF
apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: "productpage-viewer"
  namespace: default
spec:
  selector:
    matchLabels:
      app: productpage
  action: ALLOW
  rules:
  - to:
    - operation:
        methods: ["GET"]
EOF
```
Point your browser at the Bookinfo productpage (http://$GATEWAY_URL/productpage). Now you should see the “Bookinfo Sample” page. However, you can see the following errors on the page:
- Error fetching product details
- Error fetching product reviews on the page.
These errors are expected because we have not granted the productpage workload access to the details and reviews workloads. Next, you need to configure a policy to grant access to those workloads.

Run the following command to create the details-viewer policy to allow the productpage workload, which issues requests using the cluster.local/ns/default/sa/bookinfo-productpage service account, to access the details workload through GET methods:

$ kubectl apply -f - <<EOF
apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: "details-viewer"
  namespace: default
spec:
  selector:
    matchLabels:
      app: details
  action: ALLOW
  rules:
  - from:
    - source:
        principals: ["cluster.local/ns/default/sa/bookinfo-productpage"]
    to:
    - operation:
        methods: ["GET"]
EOF

Run the following command to create a policy reviews-viewer to allow the productpage workload, which issues requests using the cluster.local/ns/default/sa/bookinfo-productpage service account, to access the reviews workload through GET methods:
```
$ kubectl apply -f - <<EOF
apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: "reviews-viewer"
  namespace: default
spec:
  selector:
    matchLabels:
      app: reviews
  action: ALLOW
  rules:
  - from:
    - source:
        principals: ["cluster.local/ns/default/sa/bookinfo-productpage"]
    to:
    - operation:
        methods: ["GET"]
EOF
```
Point your browser at the Bookinfo productpage (http://$GATEWAY_URL/productpage). Now, you should see the “Bookinfo Sample” page with “Book Details” on the lower left part, and “Book Reviews” on the lower right part. However, in the “Book Reviews” section, there is an error Ratings service currently unavailable.

This is because the reviews workload doesn’t have permission to access the ratings workload. To fix this issue, you need to grant the reviews workload access to the ratings workload. Next, we configure a policy to grant the reviews workload that access.
Run the following command to create the ratings-viewer policy to allow the reviews workload, which issues requests using the cluster.local/ns/default/sa/bookinfo-reviews service account, to access the ratings workload through GET methods:
```
$ kubectl apply -f - <<EOF
apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: "ratings-viewer"
  namespace: default
spec:
  selector:
    matchLabels:
      app: ratings
  action: ALLOW
  rules:
  - from:
    - source:
        principals: ["cluster.local/ns/default/sa/bookinfo-reviews"]
    to:
    - operation:
        methods: ["GET"]
EOF
```
Point your browser at the Bookinfo productpage (http://$GATEWAY_URL/productpage). You should see the “black” and “red” ratings in the “Book Reviews” section.

Congratulations! You successfully applied authorization policy to enforce access control for workloads using HTTP traffic.

Clean up

Remove all authorization policies from your configuration:

$ kubectl delete authorizationpolicy.security.istio.io/allow-nothing
$ kubectl delete authorizationpolicy.security.istio.io/productpage-viewer
$ kubectl delete authorizationpolicy.security.istio.io/details-viewer
$ kubectl delete authorizationpolicy.security.istio.io/reviews-viewer
$ kubectl delete authorizationpolicy.security.istio.io/ratings-viewer