Use Policy Essentials v2022 policy constraints

Policy Controller comes with a default library of constraint templates that can be used with the Policy Essentials v2022 bundle to apply Google recommended best practices to your cluster resources.

This bundle of constraints addresses and enforces policies in the following domains:

• RBAC and service accounts
• Pod Security Policies
• Container Network Interface (CNI)
• Secrets management
• General policies

Policy Essentials policy bundle constraints

Constraint Name	Constraint Description
policy-essentials-v2022-no-secrets-as-env-vars	Prefer using Secrets as files over Secrets as environment variables
policy-essentials-v2022-pods-require-security-context	Apply Security Context to your Pods and containers
policy-essentials-v2022-prohibit-role-wildcard-access	Minimize the use of wildcards in Roles and ClusterRoles.
policy-essentials-v2022-psp-allow-privilege-escalation-container	Minimize the admission of containers with allowPrivilegeEscalation
policy-essentials-v2022-psp-capabilities	Containers must drop the `NET_RAW` capability and aren't permitted to add back any capabilities.
policy-essentials-v2022-psp-host-namespace	Minimize the admission of containers with `hostPID` or `hostIPC` set to `true`.
policy-essentials-v2022-psp-host-network-ports	Minimize the admission of containers wanting to share the host network namespace
policy-essentials-v2022-psp-privileged-container	Minimize the admission of privileged containers
policy-essentials-v2022-psp-pods-must-run-as-nonroot	Minimize the admission of root containers
policy-essentials-v2022-psp-seccomp-default	Ensure that the seccomp profile is set to `runtime/default` or `docker/default` in your Pod definitions
policy-essentials-v2022-restrict-clusteradmin-rolebindings	Minimize the use of the cluster-admin role.

Before you begin

1. Install and initialize the Google Cloud CLI, which provides the gcloud and kubectl commands used in these instructions. If you use Cloud Shell, Google Cloud CLI comes pre-installed.
2. Install Policy Controller v1.14.3 or higher on your cluster with the default library of constraint templates.

Audit Policy Essentials policy bundle

Policy Controller lets you enforce policies for your Kubernetes cluster. To help test your workloads and their compliance with regard to the Google recommended best practices outlined in the preceding table, you can deploy these constraints in "audit" mode to reveal violations and more importantly give yourself a chance to fix them before enforcing on your Kubernetes cluster.

You can apply these policies with spec.enforcementAction set to dryrun using kubectl, kpt, or Config Sync.

kubectl

1. (Optional) Preview the policy constraints with kubectl:

   kubectl kustomize https://github.com/GoogleCloudPlatform/gke-policy-library.git/bundles/policy-essentials-v2022
   

2. Apply the policy constraints with kubectl:

   kubectl apply -k https://github.com/GoogleCloudPlatform/gke-policy-library.git/bundles/policy-essentials-v2022
   

   The output is the following:

   k8snoenvvarsecrets.constraints.gatekeeper.sh/policy-essentials-v2022-no-secrets-as-env-vars created
   k8spspallowprivilegeescalationcontainer.constraints.gatekeeper.sh/policy-essentials-v2022-psp-allow-privilege-escalation created
   k8spspallowedusers.constraints.gatekeeper.sh/policy-essentials-v2022-psp-pods-must-run-as-nonroot created
   k8spspcapabilities.constraints.gatekeeper.sh/policy-essentials-v2022-psp-capabilities created
   k8spsphostnamespace.constraints.gatekeeper.sh/policy-essentials-v2022-psp-host-namespace created
   k8spsphostnetworkingports.constraints.gatekeeper.sh/policy-essentials-v2022-psp-host-network-ports created
   k8spspprivilegedcontainer.constraints.gatekeeper.sh/policy-essentials-v2022-psp-privileged-container created
   k8spspseccomp.constraints.gatekeeper.sh/policy-essentials-v2022-psp-seccomp-default created
   k8spodsrequiresecuritycontext.constraints.gatekeeper.sh/policy-essentials-v2022-pods-require-security-context created
   k8sprohibitrolewildcardaccess.constraints.gatekeeper.sh/policy-essentials-v2022-prohibit-role-wildcard-access created
   k8srestrictrolebindings.constraints.gatekeeper.sh/policy-essentials-v2022-restrict-clusteradmin-rolebindings created
   

3. Verify that policy constraints have been installed and check if violations exist across the cluster:

   kubectl get -k https://github.com/GoogleCloudPlatform/gke-policy-library.git/bundles/policy-essentials-v2022
   

   The output is similar to the following:

   NAME                                                                                          ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
   k8snoenvvarsecrets.constraints.gatekeeper.sh/policy-essentials-v2022-no-secrets-as-env-vars   dryrun               0
   
   NAME                                                                                                                       ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
   k8spspallowprivilegeescalationcontainer.constraints.gatekeeper.sh/policy-essentials-v2022-psp-allow-privilege-escalation   dryrun               0
   
   NAME                                                                                                ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
   k8spspallowedusers.constraints.gatekeeper.sh/policy-essentials-v2022-psp-pods-must-run-as-nonroot   dryrun               0
   
   NAME                                                                                    ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
   k8spspcapabilities.constraints.gatekeeper.sh/policy-essentials-v2022-psp-capabilities   dryrun               0
   
   NAME                                                                                       ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
   k8spsphostnamespace.constraints.gatekeeper.sh/policy-essentials-v2022-psp-host-namespace   dryrun               0
   
   NAME                                                                                                 ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
   k8spsphostnetworkingports.constraints.gatekeeper.sh/policy-essentials-v2022-psp-host-network-ports   dryrun               0
   
   NAME                                                                                                   ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
   k8spspprivilegedcontainer.constraints.gatekeeper.sh/policy-essentials-v2022-psp-privileged-container   dryrun               0
   
   NAME                                                                                  ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
   k8spspseccomp.constraints.gatekeeper.sh/policy-essentials-v2022-psp-seccomp-default   dryrun               0
   
   NAME                                                                                                            ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
   k8spodsrequiresecuritycontext.constraints.gatekeeper.sh/policy-essentials-v2022-pods-require-security-context   dryrun               0
   
   NAME                                                                                                            ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
   k8sprohibitrolewildcardaccess.constraints.gatekeeper.sh/policy-essentials-v2022-prohibit-role-wildcard-access   dryrun               0
   
   NAME                                                                                                           ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
   k8srestrictrolebindings.constraints.gatekeeper.sh/policy-essentials-v2022-restrict-clusteradmin-rolebindings   dryrun               0
   

kpt

1. Install and setup kpt. kpt is used in these instructions to customize and deploy Kubernetes resources.

2. Download the Policy Essentials v2022 policy bundle from GitHub using kpt:

   kpt pkg get https://github.com/GoogleCloudPlatform/gke-policy-library.git/bundles/policy-essentials-v2022
   

3. Run the set-enforcement-action kpt function to set the policies' enforcement action to dryrun:

   kpt fn eval policy-essentials-v2022 -i gcr.io/kpt-fn/set-enforcement-action:v0.1 \
     -- enforcementAction=dryrun
   

4. Initialize the working directory with kpt, which creates a resource to track changes:

   cd policy-essentials-v2022
   kpt live init
   

5. Apply the policy constraints with kpt:

   kpt live apply
   

   The output is the following:

   k8spspseccomp.constraints.gatekeeper.sh/policy-essentials-v2022-psp-seccomp-docker-default created
   k8spodsrequiresecuritycontext.constraints.gatekeeper.sh/policy-essentials-v2022-pods-require-security-context created
   k8sprohibitrolewildcardaccess.constraints.gatekeeper.sh/policy-essentials-v2022-prohibit-role-wildcard-access created
   k8snoenvvarsecrets.constraints.gatekeeper.sh/policy-essentials-v2022-no-secrets-as-env-vars created
   k8spspallowprivilegeescalationcontainer.constraints.gatekeeper.sh/policy-essentials-v2022-psp-allow-privilege-escalation-container created
   k8spspallowedusers.constraints.gatekeeper.sh/policy-essentials-v2022-psp-pods-must-run-as-nonroot created
   k8spsphostnetworkingports.constraints.gatekeeper.sh/policy-essentials-v2022-psp-host-network-ports created
   k8srestrictrolebindings.constraints.gatekeeper.sh/policy-essentials-v2022-restrict-clusteradmin-rolebindings created
   k8spspcapabilities.constraints.gatekeeper.sh/policy-essentials-v2022-psp-capabilities created
   k8spsphostnamespace.constraints.gatekeeper.sh/policy-essentials-v2022-psp-host-namespace created
   k8spspprivilegedcontainer.constraints.gatekeeper.sh/policy-essentials-v2022-psp-privileged-container created
   11 resource(s) applied. 11 created, 0 unchanged, 0 configured, 0 failed
   

6. Verify that policy constraints have been installed and check if violations exist across the cluster:

   kpt live status --output table --poll-until current
   

   A status of CURRENT confirms successful installation of the constraints.

Config Sync

1. Install and setup kpt. kpt is used in these instructions to customize and deploy Kubernetes resources.

Operators using Config Sync to deploy policies to their clusters can use the following instructions:

1. Change into the sync directory for Config Sync:

   cd SYNC_ROOT_DIR
   

   Note: Kpt v1.0.0-beta.17 and later automatically create a resourcegroup.yaml file during live init which shouldn't be checked into your Config Sync repo. If not already present, add resourcegroup.yaml to your repo's .gitignore file.

   To create or append .gitignore with resourcegroup.yaml:

   echo resourcegroup.yaml >> .gitignore
   

2. Create a dedicated policies directory:

   mkdir -p policies
   

3. Download the Policy Essentials v2022 policy bundle from GitHub using kpt:

   kpt pkg get https://github.com/GoogleCloudPlatform/gke-policy-library.git/bundles/policy-essentials-v2022 policies/policy-essentials-v2022
   

4. Run the set-enforcement-action kpt function to set the policies' enforcement action to dryrun:

   kpt fn eval policies/policy-essentials-v2022 -i gcr.io/kpt-fn/set-enforcement-action:v0.1 -- enforcementAction=dryrun
   

5. (Optional) Preview the policy constraints to be created:

   kpt live init policies/policy-essentials-v2022
   kpt live apply --dry-run policies/policy-essentials-v2022
   

   The output is the following:

   Dry-run strategy: client
   inventory update started
   inventory update finished
   apply phase started
   k8snoenvvarsecrets.constraints.gatekeeper.sh/policy-essentials-v2022-no-secrets-as-env-vars apply successful
   k8spspallowprivilegeescalationcontainer.constraints.gatekeeper.sh/policy-essentials-v2022-psp-allow-privilege-escalation apply successful
   k8spspallowedusers.constraints.gatekeeper.sh/policy-essentials-v2022-psp-pods-must-run-as-nonroot apply successful
   k8spspcapabilities.constraints.gatekeeper.sh/policy-essentials-v2022-psp-capabilities apply successful
   k8spsphostnamespace.constraints.gatekeeper.sh/policy-essentials-v2022-psp-host-namespace apply successful
   k8spsphostnetworkingports.constraints.gatekeeper.sh/policy-essentials-v2022-psp-host-network-ports apply successful
   k8spspprivilegedcontainer.constraints.gatekeeper.sh/policy-essentials-v2022-psp-privileged-container apply successful
   k8spspseccomp.constraints.gatekeeper.sh/policy-essentials-v2022-psp-seccomp-default apply successful
   k8spodsrequiresecuritycontext.constraints.gatekeeper.sh/policy-essentials-v2022-pods-require-security-context apply successful
   k8sprohibitrolewildcardaccess.constraints.gatekeeper.sh/policy-essentials-v2022-prohibit-role-wildcard-access apply successful
   k8srestrictrolebindings.constraints.gatekeeper.sh/policy-essentials-v2022-restrict-clusteradmin-rolebindings apply successful
   apply phase finished
   inventory update started
   inventory update finished
   apply result: 11 attempted, 11 successful, 0 skipped, 0 failed
   

6. If your sync directory for Config Sync uses Kustomize, add policies/policy-essentials-v2022 to your root kustomization.yaml. Otherwise remove the policies/policy-essentials-v2022/kustomization.yaml file:

   rm SYNC_ROOT_DIR/policies/policy-essentials-v2022/kustomization.yaml
   

7. Push changes to the Config Sync repo:

   git add SYNC_ROOT_DIR/policy-essentials-v2022
   git commit -m 'Adding Policy Essentials v2022 policy audit enforcement'
   git push
   

8. Verify the status of the installation:

   watch gcloud beta container fleet config-management status --project PROJECT_ID
   

   A status of SYNCED confirms the installation of the policies.

View policy violations

Once the policy constraints are installed in audit mode, violations on the cluster can be viewed in the UI using the Policy Controller Dashboard.

You can also use kubectl to view violations on the cluster using the following command:

kubectl get constraint -l policycontroller.gke.io/bundleName=policy-essentials-v2022 -o json | jq -cC '.items[]| [.metadata.name,.status.totalViolations]'

If violations are present, a listing of the violation messages per constraint can be viewed with:

kubectl get constraint -l policycontroller.gke.io/bundleName=policy-essentials-v2022 -o json | jq -C '.items[]| select(.status.totalViolations>0)| [.metadata.name,.status.violations[]?]'

Change Policy Essentials policy bundle enforcement action

Once you've reviewed policy violations on your cluster, you can consider changing the enforcement mode so the Admission Controller will either warn on or even deny block non-compliant resource from getting applied to the cluster.

Warning: The deny enforcement action should be used with care as it can potentially block required changes resulting in interruption to critical workloads or the cluster. It is strongly recommended that only the warn or dryrun enforcement actions are used on clusters with production workloads, when testing new constraints, or performing migrations such as upgrading platforms. For more information about enforcement actions, see Auditing using constraints.

kubectl

1. Use kubectl to set the policies' enforcement action to warn:

   kubectl get constraint -l policycontroller.gke.io/bundleName=policy-essentials-v2022 -o name | xargs -I {} kubectl patch {} --type='json' -p='[{"op":"replace","path":"/spec/enforcementAction","value":"warn"}]'
   

2. Verify that policy constraints enforcement action have been updated:

   kubectl get constraint -l policycontroller.gke.io/bundleName=policy-essentials-v2022
   

kpt

1. Run the set-enforcement-action kpt function to set the policies' enforcement action to warn:

   kpt fn eval -i gcr.io/kpt-fn/set-enforcement-action:v0.1 -- enforcementAction=warn
   

2. Apply the policy constraints:

   kpt live apply
   

Config Sync

Operators using Config Sync to deploy policies to their clusters can use the following instructions:

1. Change into the sync directory for Config Sync:

   cd SYNC_ROOT_DIR
   

2. Run the set-enforcement-action kpt function to set the policies' enforcement action to warn:

   kpt fn eval policies/policy-essentials-v2022 -i gcr.io/kpt-fn/set-enforcement-action:v0.1 -- enforcementAction=warn
   

3. Push changes to the Config Sync repo:

   git add SYNC_ROOT_DIR/policies/policy-essentials-v2022
   git commit -m 'Adding Policy Essentials policy bundle warn enforcement'
   git push
   

4. Verify the status of the installation:

   gcloud alpha anthos config sync repo list --project PROJECT_ID
   

   Your repo showing up in the SYNCED column confirms the installation of the policies.

Test policy enforcement

Create a non-compliant resource on the cluster using the following command:

cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
  namespace: default
  name: wp-non-compliant
  labels:
    app: wordpress
spec:
  containers:
    - image: wordpress
      name: wordpress
      ports:
      - containerPort: 80
        name: wordpress
EOF

The admission controller should produce a warning listing out the policy violations that this resource violates, as shown in the following example:

Warning: [policy-essentials-v2022-psp-capabilities] container <wordpress> is not dropping all required capabilities. Container must drop all of ["NET_RAW"] or "ALL"
pod/wp-non-compliant created

Remove Policy Essentials policy bundle

If needed, the Policy Essentials policy bundle can be removed from the cluster.

kubectl

• Use kubectl to remove the policies:

  kubectl delete constraint -l policycontroller.gke.io/bundleName=policy-essentials-v2022
  

kpt

• Remove the policies:

  kpt live destroy
  

Config Sync

Operators using Config Sync to deploy policies to their clusters can use the following instructions:

1. Push changes to the Config Sync repo:

   git rm -r SYNC_ROOT_DIR/policies/policy-essentials-v2022
   git commit -m 'Removing Policy Essentials v2022 policies'
   git push
   

2. Verify the status:

   gcloud alpha anthos config sync repo list --project PROJECT_ID
   

   Your repo showing up in the SYNCED column confirms the removal of the policies.