Policies #

The installation of the mirrord operator defines a custom resource named MirrordPolicy on your cluster. By creating policies you can limit the use of some features of mirrord with selected targets. In order to see a list of the features you can block in a policy you can run

kubectl get crd mirrordpolicies.policies.mirrord.metalbear.co -o jsonpath='{.spec.versions[-1].schema.openAPIV3Schema.properties.spec.properties.block.items.enum}'

You can optionally set a target path pattern and/or a label selector in order to limit the targets for which a policy applies.

The target path of a mirrord run is either targetless or has the form <TARGET_TYPE>/<NAME> followed by an optional /container/<CONTAINER_NAME>, where <TARGET_TYPE> is one of deploy, pod and rollout.

Examples for possible target paths:

  • deploy/boats
  • pod/boats-5fffb9767c-w92qh
  • pod/boats-5fffb9767c-w92qh/container/appcontainer
  • targetless

By specifying a targetPath pattern in the policy, you limit the policy to only apply to runs that have a target path that matches the specified pattern. The target path pattern can contain ? which will match a single character and * which will match arbitrarily many characters. For example, "deploy/*" will make a policy apply for any run with a deployment target. "*boats*" will make a policy apply to any target with boats in its name, e.g. pod/boats-2kljw9, pod/whatever-23oije2/container/boats-container, etc.

Note: when a container is specified for the mirrord run, the target path ends with /container/<CONTAINER_NAME>.

This means the pattern deploy/my-deployment will not match when a container is specified. That pattern can be changed to deploy/my-deployment* to also match on runs with a specified container (but will then also match deploy/my-deployment-1 etc.)

Please note that the policy is applied according to the target given to mirrord. It is possible for a policy to apply to a deployment target, but not to apply to the deployment’s pods when targeted directly. For example, the following policy:

apiVersion: policies.mirrord.metalbear.co/v1alpha
kind: MirrordPolicy
  name: block-stealing-from-boats-deployment
  namespace: default
  targetPath: "deploy/boats*"
    - steal

prevents mirrord users from stealing traffic when using the whole boats deployment as a target. However, a user could still use a specific pod out of that deployment as a target for mirrord and steal its traffic. In order to prevent that, the targetPath pattern or the label selector needs to be changed to match the pods of that deployment.

If a deployment is used as a target, the deployment’s labels will be used to match against policies’ selector, if set. If a pod is used as a target, the pod’s labels will be used.

Another example of a policy:

apiVersion: policies.mirrord.metalbear.co/v1alpha
kind: MirrordPolicy
  name: block-unfiltered-stealing-from-webserver-deployments
  namespace: books
  targetPath: "deploy/*"
      component: webserver
    - steal-without-filter