Testing and Limiting Access to the Nginx Service

## Create an `nginx` deployment and expose it via a service To see how Kubernetes network policy works, start off by creating an `nginx` Deployment. ```console kubectl create deployment nginx --image=nginx ``` ```none deployment.apps/nginx created ``` Expose the Deployment through a Service called `nginx`. ```console kubectl expose deployment nginx --port=80 ``` ```none service/nginx exposed ``` The above commands create a Deployment with an nginx Pod and expose the Deployment through a Service named `nginx`. The `nginx` Pod and Deployment are found in the `default` namespace. ```console kubectl get svc,pod ``` ```none NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE service/kubernetes 10.100.0.1 <none> 443/TCP 46m service/nginx 10.100.0.16 <none> 80/TCP 33s NAME READY STATUS RESTARTS AGE pod/nginx-701339712-e0qfq 1/1 Running 0 35s ``` ## Test the service by accessing it from another Pod You should be able to access the new `nginx` service from other Pods. To access the `nginx` Service from another Pod in the `default` namespace, start a busybox container: ```console kubectl run busybox --rm -ti --image=busybox -- /bin/sh ``` In your shell, run the following command: ```shell wget --spider --timeout=1 nginx ``` ```none Connecting to nginx (10.100.0.16:80) remote file exists ``` ## Limit access to the `nginx` service To limit the access to the `nginx` service so that only Pods with the label `access: true` can query it, create a NetworkPolicy object as follows: {{% code_sample file="service/networking/nginx-policy.yaml" %}} The name of a NetworkPolicy object must be a valid [DNS subdomain name](/docs/concepts/overview/working-with-objects/names#dns-subdomain-names). {{< note >}} NetworkPolicy includes a `podSelector` which selects the grouping of Pods to which the policy applies. You can see this policy selects Pods with the label `app=nginx`. The label was automatically added to the Pod in the `nginx` Deployment. An empty `podSelector` selects all pods in the namespace. {{< /note >}} ## Assign the policy to the service Use kubectl to create a NetworkPolicy from the above `nginx-policy.yaml` file: ```console kubectl apply -f https://k8s.io/examples/service/networking/nginx-policy.yaml ``` ```none networkpolicy.networking.k8s.io/access-nginx created ``` ## Test access to the service when access label is not defined When you attempt to access the `nginx` Service from a Pod without the correct labels, the request times out: ```console kubectl run busybox --rm -ti --image=busybox -- /bin/sh ``` In your shell, run the command: ```shell wget --spider --timeout=1 nginx ``` ```none Connecting to nginx (10.100.0.16:80) wget: download timed out ``` ## Define access label and test again You can create a Pod with the correct labels to see that the request is allowed: ```console kubectl run busybox --rm -ti --labels="access=true" --image=busybox -- /bin/sh ``` In your shell, run the command: ```shell wget --spider --timeout=1 nginx ``` ```none Connecting to nginx (10.100.0.16:80) remote file exists ```

This section details how to test the newly created nginx service by accessing it from another pod. It then guides you through limiting access to the nginx service using a NetworkPolicy, allowing only pods with the `access: true` label to query it. The process includes creating a NetworkPolicy object, applying it, and testing access from pods with and without the specified label to verify the policy's effect.