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15-Labs-OPA-in-Kubernetes.md

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Lab - OPA in Kubernetes

  • Take me to the Lab

Solutions for Lab - OPA in Kubernetes:

  1. Which is not a function of Kube-mgmt?
    Reveal

    Manage kubernetes objects via OPA is not a function of Kube-mgmt.

  2. What needs to be done to enable kube-mgmt to automatically identify policies defined in kubernetes and load them into OPA?
    • Create configmaps on Kubernetes with the label openpolicyagent.org/policy set to rego
    • Create configmaps on Kubernetes with label set to OPA
    • Create secrets on Kubernetes with name start opa-
    • Create configmaps on Kubernetes with name start opa-
    Reveal

    Create configmaps on Kubernetes with the label openpolicyagent.org/policy set to rego needs to be done to enable kube-mgmt to automatically identify policies defined in kubernetes and load them into OPA.

  3. We have placed rego policies under /root/untrusted-registry.rego and /root/unique-host.rego. View the contents of these files and identify which kubernetes resources will be validated by these rego policies?

    Check input.request.kind.kind in rego policies file

    • untrusted-registry.rego : pod ; unique-host.rego : pod
    • untrusted-registry.rego : ingress ; unique-host.rego : ingress
    • untrusted-registry.rego : ingress ; unique-host.rego : ingress
    • untrusted-registry.rego : ingress ; unique-host.rego : pod
    Reveal

    untrusted-registry.rego : pod ; unique-host.rego : ingress

  4. If we were to implement the policy under /root/untrusted-registry.rego and create a pod as defined in /root/test.yaml, which of the 2 containers will error out?

    untrusted-registry.rego policy denies pods with image name that does not start with hooli.com/

    • both
    • mysql-backend
    • nginx-frontend
    • none
    Reveal

    nginx-frontend

  5. Create a configmap for OPA using the untrusted-registry.rego policy

    Use below files:

    • configmap file: /root/untrusted-registry.rego
    • configmap name : untrusted-registry

    Remember from CKA how to create a configmap from a file imperatively.

    Reveal 
    kubectl create configmap untrusted-registry --from-file=untrusted-registry.rego
  6. Create a pod defined under /root/test.yaml in the namespace dev. Fix the OPA validation issue while creating the pod.

    NOTE: The pod is expected to be in a created state but not up and running.

    Recall that the untrusted registry policy denies creation of pods not from a certain registry named in the policy.

    Try applying the manifest as-is and observe the error

    kubectl apply -n dev -f /root/test.yaml
    Reveal

    1. Edit test.yaml and ensure all container images start with hooli.com/

    2. Apply the edited manifest

      kubectl apply -n dev -f /root/test.yaml
  7. As per policy in /root/unique-host.rego, which ingress resources will be denied for creation?
    • multiple ingress resources with same namespace
    • multiple ingress resources with same service
    • multiple ingress resources with same host
    • multiple ingress resources with same image name

    Check the Ingress object being compared in the /root/unique-host.rego policy

    Reveal

    The following two lines in the policy give away the answer

    • host := input.request.object.spec.rules[_].host
    • msg := sprintf("invalid ingress host %q (conflicts with %v/%v)", [host, other_ns, other_ingress])

    The4 object being compared is the ingress host, and the policy is to prevent you from being able to create two ingresses referring to the same host - which is a good thing as it would confuse the ingress controller.

    multiple ingress resources with same host

  8. Create a configmap named unique-host using the rego file /root/unique-host.rego for OPA.

    Do the same as for Q5, but for the other rego file.

    Reveal 
    kubectl create configmap unique-host --from-file=/root/unique-host.rego
  9. Create 2 ingress resources using below files. Check if you can create both resources
    • /root/ingress-test-1.yaml
    • /root/ingress-test-2.yaml
    Reveal 
    kubectl apply -f /root/ingress-test-1.yaml
kubectl apply -f /root/ingress-test-2.yaml

    ingress-test-2 fails with an error. If you examine both YAML files, you will see that they both refer to the same host initech.com which is in violation of the policy.

    Note also that if you created #2 first, then it would create and #1 would fail with that error.