apply

The apply command is used to perform a dry run on one or more policies with a given set of input resources. This can be useful to determine a policy’s effectiveness prior to committing to a cluster. In the case of mutate policies, the apply command can show the mutated resource as an output. The input resources can either be resource manifests (one or multiple) or can be taken from a running Kubernetes cluster. The apply command supports files from URLs both as policies and resources.

Apply to a resource:

1kyverno apply /path/to/policy.yaml --resource /path/to/resource.yaml

Apply a policy to all matching resources in a cluster based on the current kubectl context:

1kyverno apply /path/to/policy.yaml --cluster

The resources can also be passed from stdin:

1kustomize build nginx/overlays/envs/prod/ | kyverno apply /path/to/policy.yaml --resource -

Apply all cluster policies in the current cluster to all matching resources in a cluster based on the current kubectl context:

1kubectl get clusterpolicies -o yaml | kyverno apply - --cluster

Apply multiple policies to multiple resources:

1kyverno apply /path/to/policy1.yaml /path/to/folderFullOfPolicies --resource /path/to/resource1.yaml --resource /path/to/resource2.yaml --cluster

Apply a policy to a resource with a policy exception:

1kyverno apply /path/to/policy.yaml --resource /path/to/resource.yaml --exception /path/to/exception.yaml

Apply multiple policies to multiple resources with exceptions:

1kyverno apply /path/to/policy1.yaml /path/to/folderFullOfPolicies --resource /path/to/resource1.yaml --resource /path/to/resource2.yaml --exception /path/to/exception1.yaml --exception /path/to/exception2.yaml

Apply multiple policies to multiple resources where exceptions are evaluated from the provided resources:

1kyverno apply /path/to/policy1.yaml /path/to/folderFullOfPolicies --resource /path/to/resource1.yaml --resource /path/to/resource2.yaml --exceptions-with-resources

Apply a mutation policy to a specific resource:

1kyverno apply /path/to/policy.yaml --resource /path/to/resource.yaml
2
3applying 1 policy to 1 resource... 
4
5mutate policy <policy_name> applied to <resource_name>:
6<final mutated resource output>

Save the mutated resource to a file:

1kyverno apply /path/to/policy.yaml --resource /path/to/resource.yaml -o newresource.yaml

Save the mutated resource to a directory:

1kyverno apply /path/to/policy.yaml --resource /path/to/resource.yaml -o foo/

Run a policy with a mutate existing rule on a group of target resources:

 1kyverno apply /path/to/policy.yaml --resource /path/to/resource.yaml  --target-resource /path/to/target1.yaml --target-resource /path/to/target2.yaml
 2
 3Applying 1 policy rule(s) to 1 resource(s)...
 4
 5mutate policy <policy-name> applied to <trigger-name>:
 6<trigger-resource>
 7---
 8patched targets:
 9
10<patched-target1>
11
12---
13
14<patched-target2>
15
16---
17
18pass: 2, fail: 0, warn: 0, error: 0, skip: 0

Run a policy with a mutate existing rule on target resources from a directory:

 1kyverno apply /path/to/policy.yaml --resource /path/to/resource.yaml  --target-resources /path/to/targets/
 2
 3Applying 1 policy rule(s) to 1 resource(s)...
 4
 5mutate policy <policy-name> applied to <trigger-name>:
 6<trigger-resource>
 7---
 8patched targets:
 9
10<patched-targets>
11
12pass: 5, fail: 0, warn: 0, error: 0, skip: 0

Apply a policy containing variables using the --set or -s flag to pass in the values. Variables that begin with {{request.object}} normally do not need to be specified as these will be read from the resource.

1kyverno apply /path/to/policy.yaml --resource /path/to/resource.yaml --set <variable1>=<value1>,<variable2>=<value2>

Use -f or --values-file for applying multiple policies to multiple resources while passing a file containing variables and their values. Variables specified can be of various types include AdmissionReview fields, ConfigMap context data, API call context data, and Global Context Entries.

Use -u or --userinfo for applying policies while passing an optional user_info.yaml file which contains necessary admission request data made during the request.

1kyverno apply /path/to/policy1.yaml /path/to/policy2.yaml --resource /path/to/resource1.yaml --resource /path/to/resource2.yaml -f /path/to/value.yaml --userinfo /path/to/user_info.yaml

Format of value.yaml with all possible fields:

 1apiVersion: cli.kyverno.io/v1alpha1
 2kind: Values
 3metadata:
 4  name: values
 5policies:
 6  - name: <policy1 name>
 7    rules:
 8    - name: <rule1 name>
 9      values:
10        <context variable1 in policy1 rule1>: <value>
11        <context variable2 in policy1 rule1>: <value>
12    - name: <rule2 name>
13      values:
14        <context variable1 in policy1 rule2>: <value>
15        <context variable2 in policy1 rule2>: <value>
16    resources:
17    - name: <resource1 name>
18      values:
19        <variable1 in policy1>: <value>
20        <variable2 in policy1>: <value>
21    - name: <resource2 name>
22      values:
23        <variable1 in policy1>: <value>
24        <variable2 in policy1>: <value>
25namespaceSelector:
26- name: <namespace1 name>
27  labels:
28    <label key>: <label value>
29- name: <namespace2 name>
30  labels:
31    <label key>: <label value>

Format of user_info.yaml:

1apiVersion: cli.kyverno.io/v1alpha1
2kind: UserInfo
3metadata:
4  name: user-info
5clusterRoles:
6- admin
7userInfo:
8  username: molybdenum@somecorp.com

Example:

Policy manifest (add_network_policy.yaml):

 1apiVersion: kyverno.io/v1
 2kind: ClusterPolicy
 3metadata:
 4  name: add-networkpolicy
 5spec:
 6  background: false
 7  rules:
 8  - name: default-deny-ingress
 9    match:
10      any:
11      - resources:
12          kinds:
13          - Namespace
14        clusterRoles:
15        - cluster-admin
16    generate:
17      apiVersion: networking.k8s.io/v1
18      kind: NetworkPolicy
19      name: default-deny-ingress
20      namespace: "{{request.object.metadata.name}}"
21      synchronize: true
22      data:
23        spec:
24          # select all pods in the namespace
25          podSelector: {}
26          policyTypes:
27          - Ingress

Resource manifest (required_default_network_policy.yaml):

1kind: Namespace
2apiVersion: v1
3metadata:
4  name: devtest

Apply a policy to a resource using the --set or -s flag to pass a variable directly:

1kyverno apply /path/to/add_network_policy.yaml --resource /path/to/required_default_network_policy.yaml -s request.object.metadata.name=devtest

Apply a policy to a resource using the --values-file or -f flag:

YAML file containing variables (value.yaml):

 1apiVersion: cli.kyverno.io/v1alpha1
 2kind: Values
 3metadata:
 4  name: values
 5policies:
 6  - name: add-networkpolicy
 7    resources:
 8      - name: devtest
 9        values:
10          request.namespace: devtest

1kyverno apply /path/to/add_network_policy.yaml --resource /path/to/required_default_network_policy.yaml -f /path/to/value.yaml

On applying the above policy to the mentioned resources, the following output will be generated:

1Applying 1 policy to 1 resource... 
2(Total number of result count may vary as the policy is mutated by Kyverno. To check the mutated policy please try with log level 5)
3
4pass: 1, fail: 0, warn: 0, error: 0, skip: 0

The summary count is based on the number of rules applied on the number of resources.

Value files also support global values, which can be passed to all resources the policy is being applied to.

Format of value.yaml:

 1apiVersion: cli.kyverno.io/v1alpha1
 2kind: Values
 3metadata:
 4  name: values
 5policies:
 6  - name: <policy1 name>
 7    resources:
 8      - name: <resource1 name>
 9        values:
10          <variable1 in policy1>: <value>
11          <variable2 in policy1>: <value>
12      - name: <resource2 name>
13        values:
14          <variable1 in policy1>: <value>
15          <variable2 in policy1>: <value>
16  - name: <policy2 name>
17    resources:
18      - name: <resource1 name>
19        values:
20          <variable1 in policy2>: <value>
21          <variable2 in policy2>: <value>
22      - name: <resource2 name>
23        values:
24          <variable1 in policy2>: <value>
25          <variable2 in policy2>: <value>
26globalValues:
27  <global variable1>: <value>
28  <global variable2>: <value>

If a resource-specific value and a global value have the same variable name, the resource value takes precedence over the global value. See the Pod test-global-prod in the following example.

Example:

Policy manifest (add_dev_pod.yaml):

 1apiVersion: kyverno.io/v1
 2kind: ClusterPolicy
 3metadata:
 4  name: cm-globalval-example
 5spec:
 6  background: false
 7  rules:
 8    - name: validate-mode
 9      match:
10        any:
11        - resources:
12            kinds:
13              - Pod
14      validate:
15        failureAction: Enforce
16        message: "The value {{ request.mode }} for val1 is not equal to 'dev'."
17        deny:
18          conditions:
19            any:
20              - key: "{{ request.mode }}"
21                operator: NotEquals
22                value: dev

Resource manifest (dev_prod_pod.yaml):

 1apiVersion: v1
 2kind: Pod
 3metadata:
 4  name: test-global-prod
 5spec:
 6  containers:
 7    - name: nginx
 8      image: nginx:latest
 9---
10apiVersion: v1
11kind: Pod
12metadata:
13  name: test-global-dev
14spec:
15  containers:
16    - name: nginx
17      image: nginx:1.12

YAML file containing variables (value.yaml):

 1apiVersion: cli.kyverno.io/v1alpha1
 2kind: Values
 3metadata:
 4  name: values
 5policies:
 6  - name: cm-globalval-example
 7    resources:
 8      - name: test-global-prod
 9        values:
10          request.mode: prod
11globalValues:
12  request.mode: dev

1kyverno apply /path/to/add_dev_pod.yaml --resource /path/to/dev_prod_pod.yaml -f /path/to/value.yaml

The Pod test-global-dev passes the validation, and test-global-prod fails.

Apply a policy with the Namespace selector:

Use --values-file or -f for passing a file containing Namespace details. Check here to know more about Namespace selectors.

1kyverno apply /path/to/policy1.yaml /path/to/policy2.yaml --resource /path/to/resource1.yaml --resource /path/to/resource2.yaml -f /path/to/value.yaml

Format of value.yaml:

 1apiVersion: cli.kyverno.io/v1alpha1
 2kind: Values
 3metadata:
 4  name: values
 5namespaceSelector:
 6  - name: <namespace1 name>
 7    labels:
 8      <namespace label key>: <namespace label value>
 9  - name: <namespace2 name>
10    labels:
11      <namespace label key>: <namespace label value>

Example:

Policy manifest (enforce-pod-name.yaml):

 1apiVersion: kyverno.io/v1
 2kind: ClusterPolicy
 3metadata:
 4  name: enforce-pod-name
 5spec:
 6  background: true
 7  rules:
 8    - name: validate-name
 9      match:
10        any:
11        - resources:
12            kinds:
13              - Pod
14            namespaceSelector:
15              matchExpressions:
16              - key: foo.com/managed-state
17                operator: In
18                values:
19                - managed
20      validate:
21        failureAction: Audit
22        message: "The Pod must end with -nginx"
23        pattern:
24          metadata:
25            name: "*-nginx"

Resource manifest (nginx.yaml):

1kind: Pod
2apiVersion: v1
3metadata:
4  name: test-nginx
5  namespace: test1
6spec:
7  containers:
8  - name: nginx
9    image: nginx:latest

Namespace manifest (namespace.yaml):

1apiVersion: v1
2kind: Namespace
3metadata:
4  name: test1
5  labels:
6    foo.com/managed-state: managed

YAML file containing variables (value.yaml):

1apiVersion: cli.kyverno.io/v1alpha1
2kind: Values
3metadata:
4  name: values
5namespaceSelector:
6  - name: test1
7    labels:
8      foo.com/managed-state: managed

To test the above policy, use the following command:

1kyverno apply /path/to/enforce-pod-name.yaml --resource /path/to/nginx.yaml -f /path/to/value.yaml

Apply a resource to a policy which uses a context variable:

Use --values-file or -f for passing a file containing the context variable.

1kyverno apply /path/to/policy1.yaml --resource /path/to/resource1.yaml -f /path/to/value.yaml

policy1.yaml

 1apiVersion: kyverno.io/v1
 2kind: ClusterPolicy
 3metadata:
 4  name: cm-variable-example
 5  annotations:
 6    pod-policies.kyverno.io/autogen-controllers: DaemonSet,Deployment,StatefulSet
 7spec:
 8  background: false
 9  rules:
10    - name: example-configmap-lookup
11      context:
12      - name: dictionary
13        configMap:
14          name: mycmap
15          namespace: default
16      match:
17        any:
18        - resources:
19            kinds:
20            - Pod
21      mutate:
22        patchStrategicMerge:
23          metadata:
24            labels:
25              my-environment-name: "{{dictionary.data.env}}"

resource1.yaml

1apiVersion: v1
2kind: Pod
3metadata:
4  name: nginx-config-test
5spec:
6  containers:
7  - image: nginx:latest
8    name: test-nginx

value.yaml

 1apiVersion: cli.kyverno.io/v1alpha1
 2kind: Values
 3metadata:
 4  name: values
 5policies:
 6  - name: cm-variable-example
 7    rules:
 8      - name: example-configmap-lookup
 9        values:
10          dictionary.data.env: dev1

You can also inject global context entries using variables. Here’s an example of a Values file that injects a global context entry:

 1apiVersion: cli.kyverno.io/v1alpha1
 2kind: Value
 3metadata:
 4  name: values
 5globalValues:
 6  request.operation: CREATE
 7policies:
 8  - name: gctx
 9    rules:
10      - name: main-deployment-exists
11        values:
12          deploymentCount: 1

In this example, request.operation is set as a global value, and deploymentCount is set for a specific rule in the gctx policy.

Policies that have their failureAction set to Audit can be set to produce a warning instead of a failure using the --audit-warn flag. This will also cause a non-zero exit code if no enforcing policies failed.

1kyverno apply /path/to/policy.yaml --resource /path/to/resource.yaml --audit-warn

Additionally, you can use the --warn-exit-code flag with the apply command to control the exit code when warnings are reported. This is useful in CI/CD systems when used with the --audit-warn flag to treat Audit policies as warnings. When no failures or errors are found, but warnings are encountered, the CLI will exit with the defined exit code.

1kyverno apply disallow-latest-tag.yaml --resource=echo-test.yaml --audit-warn --warn-exit-code 3
2echo $?
33

You can also use --warn-exit-code in combination with --warn-no-pass flag to make the CLI exit with the warning code if no objects were found that satisfy a policy. This may be useful during the initial development of a policy or if you want to make sure that an object exists in the Kubernetes manifest.

1kyverno apply disallow-latest-tag.yaml --resource=empty.yaml --warn-exit-code 3 --warn-no-pass
2echo $?
33

Policy Report

Policy reports provide information about policy execution and violations. Use --policy-report with the apply command to generate a policy report for validate policies. mutate and generate policies do not trigger policy reports.

Policy reports can also be generated for a live cluster. While generating a policy report for a live cluster the -r flag, which declares a resource, is assumed to be globally unique. And it doesn’t support naming the resource type (ex., Pod/foo when the cluster contains resources of different types with the same name). To generate a policy report for a live cluster use --cluster with --policy-report.

1kyverno apply policy.yaml --cluster --policy-report

Above example applies a policy.yaml to all resources in the cluster.

Below are the combination of inputs that can be used for generating the policy report from the Kyverno CLI.

PolicyResourceClusterNamespaceInterpretation
policy.yaml-r resource.yamlfalseApply policy from policy.yaml to the resources specified in resource.yaml
policy.yaml-r resourceNametrueApply policy from policy.yaml to the resource with a given name in the cluster
policy.yamltrueApply policy from policy.yaml to all the resources in the cluster
policy.yaml-r resourceNametrue-n=namespaceNameApply policy from policy.yaml to the resource with a given name in a specific Namespace
policy.yamltrue-n=namespaceNameApply policy from policy.yaml to all the resources in a specific Namespace

Example:

Consider the following policy and resources:

policy.yaml

 1apiVersion: kyverno.io/v1
 2kind: ClusterPolicy
 3metadata:
 4  name: require-pod-requests-limits
 5spec:
 6  rules:
 7  - name: validate-resources
 8    match:
 9      any:
10      - resources:
11          kinds:
12          - Pod
13    validate:
14      failureAction: Audit
15      message: "CPU and memory resource requests and limits are required"
16      pattern:
17        spec:
18          containers:
19          - resources:
20              requests:
21                memory: "?*"
22                cpu: "?*"
23              limits:
24                memory: "?*"

resource1.yaml

 1apiVersion: v1
 2kind: Pod
 3metadata:
 4  name: nginx1
 5  labels:
 6    env: test
 7spec:
 8  containers:
 9  - name: nginx
10    image: nginx
11    imagePullPolicy: IfNotPresent
12    resources:
13      requests:
14        memory: "64Mi"
15        cpu: "250m"
16      limits:
17        memory: "128Mi"
18        cpu: "500m"

resource2.yaml

 1apiVersion: v1
 2kind: Pod
 3metadata:
 4  name: nginx2
 5  labels:
 6    env: test
 7spec:
 8  containers:
 9  - name: nginx
10    image: nginx
11    imagePullPolicy: IfNotPresent

Case 1: Apply a policy manifest to multiple resource manifests

1kyverno apply policy.yaml -r resource1.yaml -r resource2.yaml --policy-report

Case 2: Apply a policy manifest to multiple resources in the cluster

Create the resources by first applying manifests resource1.yaml and resource2.yaml.

1kyverno apply policy.yaml -r nginx1 -r nginx2 --cluster --policy-report

Case 3: Apply a policy manifest to all resources in the cluster

1kyverno apply policy.yaml --cluster --policy-report

Given the contents of policy.yaml shown earlier, this will produce a report validating against all Pods in the cluster.

Case 4: Apply a policy manifest to multiple resources by name within a specific Namespace

1kyverno apply policy.yaml -r nginx1 -r nginx2 --cluster --policy-report -n default

Case 5: Apply a policy manifest to all resources within the default Namespace

1kyverno apply policy.yaml --cluster --policy-report -n default

Given the contents of policy.yaml shown earlier, this will produce a report validating all Pods within the default Namespace.

On applying policy.yaml to the mentioned resources, the following report will be generated:

 1apiVersion: wgpolicyk8s.io/v1alpha1
 2kind: ClusterPolicyReport
 3metadata:
 4  name: clusterpolicyreport
 5results:
 6- message: Validation rule 'validate-resources' succeeded.
 7  policy: require-pod-requests-limits
 8  resources:
 9  - apiVersion: v1
10    kind: Pod
11    name: nginx1
12    namespace: default
13  rule: validate-resources
14  scored: true
15  status: pass
16- message: 'Validation error: CPU and memory resource requests and limits are required; Validation rule validate-resources failed at path /spec/containers/0/resources/limits/'
17  policy: require-pod-requests-limits
18  resources:
19  - apiVersion: v1
20    kind: Pod
21    name: nginx2
22    namespace: default
23  rule: validate-resources
24  scored: true
25  status: fail
26summary:
27  error: 0
28  fail: 1
29  pass: 1
30  skip: 0
31  warn: 0

Applying Policy Exceptions

Policy Exceptions can be applied alongside policies by using the -e or --exceptions flag to pass the Policy Exception manifest.

1kyverno apply /path/to/policy.yaml --resource /path/to/resource.yaml --exception /path/to/exception.yaml

Example:

Applying a policy to a resource with a policy exception.

Policy manifest (policy.yaml):

 1apiVersion: kyverno.io/v1
 2kind: ClusterPolicy
 3metadata:
 4  name: max-containers
 5spec:
 6  background: false
 7  rules:
 8  - name: max-two-containers
 9    match:
10      any:
11      - resources:
12          kinds:
13          - Pod
14    validate:
15      failureAction: Enforce
16      message: "A maximum of 2 containers are allowed inside a Pod."
17      deny:
18        conditions:
19          any:
20          - key: "{{request.object.spec.containers[] | length(@)}}"
21            operator: GreaterThan
22            value: 2

Policy Exception manifest (exception.yaml):

 1apiVersion: kyverno.io/v2
 2kind: PolicyException
 3metadata:
 4  name: container-exception
 5spec:
 6  exceptions:
 7  - policyName: max-containers
 8    ruleNames:
 9    - max-two-containers
10    - autogen-max-two-containers
11  match:
12    any:
13    - resources:
14        kinds:
15        - Pod
16        - Deployment
17  conditions:
18    any:
19    - key: "{{ request.object.metadata.labels.color || '' }}"
20      operator: Equals
21      value: blue

Resource manifest (resource.yaml):

A Deployment matching the characteristics defined in the PolicyException, shown below, will be allowed creation even though it technically violates the rule’s definition.

 1apiVersion: apps/v1
 2kind: Deployment
 3metadata:
 4  name: three-containers-deployment
 5  labels:
 6    app: my-app
 7    color: blue
 8spec:
 9  replicas: 3
10  selector:
11    matchLabels:
12      app: my-app
13  template:
14    metadata:
15      labels:
16        app: my-app
17        color: blue
18    spec:
19      containers:
20        - name: nginx-container
21          image: nginx:latest
22          ports:
23            - containerPort: 80
24        - name: redis-container
25          image: redis:latest
26          ports:
27            - containerPort: 6379
28        - name: busybox-container
29          image: busybox:latest
30          command: ["/bin/sh", "-c", "while true; do echo 'Hello from BusyBox'; sleep 10; done"]

Apply the above policy to the resource with the exception

1kyverno apply /path/to/policy.yaml --resource /path/to/resource.yaml --exception /path/to/exception.yaml

The following output will be generated:

1Applying 3 policy rule(s) to 1 resource(s) with 1 exception(s)...
2
3pass: 0, fail: 0, warn: 0, error: 0, skip: 1

Kubernetes Native Policies

The kyverno apply command can be used to apply native Kubernetes policies and their corresponding bindings to resources, allowing you to test them locally without a cluster.

ValidatingAdmissionPolicy

With the apply command, Kubernetes ValidatingAdmissionPolicies can be applied to resources as follows:

Policy manifest (check-deployment-replicas.yaml):

 1apiVersion: admissionregistration.k8s.io/v1
 2kind: ValidatingAdmissionPolicy
 3metadata:
 4  name: check-deployments-replicas
 5spec:
 6  failurePolicy: Fail
 7  matchConstraints:
 8    resourceRules:
 9    - apiGroups:   ["apps"]
10      apiVersions: ["v1"]
11      operations:  ["CREATE", "UPDATE"]
12      resources:   ["deployments"]
13  validations:
14    - expression: "object.spec.replicas <= 3"
15      message: "Replicas must be less than or equal 3"

Resource manifest (deployment.yaml):

 1apiVersion: apps/v1
 2kind: Deployment
 3metadata:
 4  name: nginx-pass
 5spec:
 6  replicas: 2
 7  selector:
 8    matchLabels:
 9      app: nginx-pass
10  template:
11    metadata:
12      labels:
13        app: nginx-pass
14    spec:
15      containers:
16      - name: nginx-server
17        image: nginx

Apply the ValidatingAdmissionPolicy to the resource:

1kyverno apply /path/to/check-deployment-replicas.yaml --resource /path/to/deployment.yaml

The following output will be generated:

1Applying 1 policy rule(s) to 1 resource(s)...
2
3pass: 1, fail: 0, warn: 0, error: 0, skip: 0

The below example applies a ValidatingAdmissionPolicyBinding along with the policy to all resources in the cluster.

Policy manifest (check-deployment-replicas.yaml):

 1apiVersion: admissionregistration.k8s.io/v1
 2kind: ValidatingAdmissionPolicy
 3metadata:
 4  name: "check-deployment-replicas"
 5spec:
 6  matchConstraints:
 7    resourceRules:
 8    - apiGroups:
 9      - apps
10      apiVersions:
11      - v1
12      operations:
13      - CREATE
14      - UPDATE
15      resources:
16      - deployments
17  validations:
18  - expression: object.spec.replicas <= 5
19---
20apiVersion: admissionregistration.k8s.io/v1
21kind: ValidatingAdmissionPolicyBinding
22metadata:
23  name: "check-deployment-replicas-binding"
24spec:
25  policyName: "check-deployment-replicas"
26  validationActions: [Deny]
27  matchResources:
28    namespaceSelector:
29      matchLabels:
30        environment: staging

The above policy verifies that the number of deployment replicas is not greater than 5 and is limited to a namespace labeled environment: staging.

Create a Namespace with the label environment: staging:

1kubectl create ns staging
2kubectl label ns staging environment=staging

Create two Deployments, one of them in the staging namespace, which violates the policy.

1kubectl create deployment nginx-1 --image=nginx --replicas=6 -n staging
2kubectl create deployment nginx-2 --image=nginx --replicas=6

Get all Deployments from the cluster:

1kubectl get deployments -A
2
3NAMESPACE            NAME                     READY   UP-TO-DATE   AVAILABLE   AGE
4default              nginx-2                  6/6     6            6           7m26s
5kube-system          coredns                  2/2     2            2           13m
6local-path-storage   local-path-provisioner   1/1     1            1           13m
7staging              nginx-1                  6/6     6            6           7m44s

Apply the ValidatingAdmissionPolicy with its binding to all resources in the cluster:

1kyverno apply /path/to/check-deployment-replicas.yaml --cluster --policy-report

The following output will be generated:

 1Applying 1 policy rule(s) to 4 resource(s)...
 2----------------------------------------------------------------------
 3POLICY REPORT:
 4----------------------------------------------------------------------
 5apiVersion: wgpolicyk8s.io/v1alpha2
 6kind: ClusterPolicyReport
 7metadata:
 8  creationTimestamp: null
 9  name: merged
10results:
11- message: 'failed expression: object.spec.replicas <= 5'
12  policy: check-deployment-replicas
13  resources:
14  - apiVersion: apps/v1
15    kind: Deployment
16    name: nginx-1
17    namespace: staging
18    uid: a95d1594-44a7-4c8a-9225-04ac34cb9494
19  result: fail
20  scored: true
21  source: kyverno
22  timestamp:
23    nanos: 0
24    seconds: 1707394871
25summary:
26  error: 0
27  fail: 1
28  pass: 0
29  skip: 0
30  warn: 0

As expected, the policy is only applied to nginx-1 as it matches both the policy definition and its binding.

MutatingAdmissionPolicy

Similarly, you can test a MutatingAdmissionPolicy to preview the changes it would make to a resource. The CLI will output the final, mutated resource.

Example 1: Basic Mutation

For instance, you can test a MutatingAdmissionPolicy that adds a label to a ConfigMap.

Policy manifest (add-label-to-configmap.yaml):

 1apiVersion: admissionregistration.k8s.io/v1alpha1
 2kind: MutatingAdmissionPolicy
 3metadata:
 4  name: "add-label-to-configmap"
 5spec:
 6  matchConstraints:
 7    resourceRules:
 8    - apiGroups:   [""]
 9      apiVersions: ["v1"]
10      operations:  ["CREATE"]
11      resources:   ["configmaps"]
12  failurePolicy: Fail
13  reinvocationPolicy: Never
14  mutations:
15    - patchType: "ApplyConfiguration"
16      applyConfiguration:
17        expression: >
18          object.metadata.?labels["lfx-mentorship"].hasValue() ? 
19              Object{} :
20              Object{ metadata: Object.metadata{ labels: {"lfx-mentorship": "kyverno"}}}

Resource manifest (configmap.yaml):

1apiVersion: v1
2kind: ConfigMap
3metadata:
4  name: game-demo
5  labels:
6    app: game
7data:
8  player_initial_lives: "3"

Now, apply the MutatingAdmissionPolicy to the ConfigMap resource:

1kyverno apply /path/to/add-label-to-configmap.yaml --resource /path/to/configmap.yaml

The output will show the mutated ConfigMap with the added label:

 1Applying 1 policy rule(s) to 1 resource(s)...
 2
 3policy add-label-to-configmap applied to default/ConfigMap/game-demo:
 4apiVersion: v1
 5data:
 6  player_initial_lives: "3"
 7kind: ConfigMap
 8metadata:
 9  labels:
10    app: game
11    lfx-mentorship: kyverno
12  name: game-demo
13  namespace: default
14---
15
16Mutation has been applied successfully.
17pass: 1, fail: 0, warn: 0, error: 0, skip: 0

The output displays the ConfigMap with the new lfx-mentorship: kyverno label, confirming the mutation was applied correctly.

Example 2: Mutation with a Binding and Namespace Selector

You can also test policies that include a MutatingAdmissionPolicyBinding to control where the policy is applied. This example makes use of a namespace selector to apply the policy only to ConfigMaps in a specific namespace.

To do this, you must provide a values.yaml file to simulate the labels of the Namespaces your resources belong to.

Policy manifest (add-label-to-configmap.yaml):

This file defines a policy to add a label and a binding that restricts it to Namespaces labeled environment: staging or environment: production.

 1apiVersion: admissionregistration.k8s.io/v1alpha1
 2kind: MutatingAdmissionPolicy
 3metadata:
 4  name: "add-label-to-configmap"
 5spec:
 6  matchConstraints:
 7    resourceRules:
 8    - apiGroups:   [""]
 9      apiVersions: ["v1"]
10      operations:  ["CREATE"]
11      resources:   ["configmaps"]
12  failurePolicy: Fail
13  reinvocationPolicy: Never
14  mutations:
15    - patchType: "ApplyConfiguration"
16      applyConfiguration:
17        expression: >
18          object.metadata.?labels["lfx-mentorship"].hasValue() ? 
19              Object{} :
20              Object{ metadata: Object.metadata{ labels: {"lfx-mentorship": "kyverno"}}}
21---
22apiVersion: admissionregistration.k8s.io/v1alpha1
23kind: MutatingAdmissionPolicyBinding
24metadata:
25  name: "add-label-to-configmap-binding"
26spec:
27  policyName: "add-label-to-configmap"
28  matchResources:
29    namespaceSelector:
30      matchExpressions:
31      - key: environment
32        operator: In
33        values:
34        - staging
35        - production

Resource manifest (configmaps.yaml):

This file contains three ConfigMap resources in different Namespaces. Only the ones in staging and production should be mutated.

 1apiVersion: v1
 2kind: ConfigMap
 3metadata:
 4  name: matched-cm-1
 5  namespace: staging
 6  labels:
 7    color: red
 8data:
 9  player_initial_lives: "3"
10---
11apiVersion: v1
12kind: ConfigMap
13metadata:
14  name: matched-cm-2
15  namespace: production
16  labels:
17    color: red
18data:
19  player_initial_lives: "3"
20---
21apiVersion: v1
22kind: ConfigMap
23metadata:
24  name: unmatched-cm
25  namespace: testing
26  labels:
27    color: blue
28data:
29  player_initial_lives: "3"

Values file (values.yaml):

This file provides the necessary context. It tells the Kyverno CLI what labels are associated with the staging, production, and testing Namespaces so it can correctly evaluate the namespaceSelector in the binding.

 1apiVersion: cli.kyverno.io/v1alpha1
 2kind: Value
 3metadata:
 4  name: values
 5namespaceSelector:
 6- labels:
 7    environment: staging
 8  name: staging
 9- labels:
10    environment: production
11  name: production
12- labels:
13    environment: testing
14  name: testing

Now, apply the MutatingAdmissionPolicy and its binding to the ConfigMaps:

1kyverno apply /path/to/add-label-to-configmap.yaml --resource /path/to/configmaps.yaml -f /path/to/values.yaml

The output will show the mutated ConfigMaps in the staging and production Namespaces, while the one in the testing Namespace remains unchanged:

 1Applying 1 policy rule(s) to 3 resource(s)...
 2
 3policy add-label-to-configmap applied to staging/ConfigMap/matched-cm-1:
 4apiVersion: v1
 5data:
 6  player_initial_lives: "3"
 7kind: ConfigMap
 8metadata:
 9  labels:
10    color: red
11    lfx-mentorship: kyverno
12  name: matched-cm-1
13  namespace: staging
14---
15
16Mutation has been applied successfully.
17policy add-label-to-configmap applied to production/ConfigMap/matched-cm-2:
18apiVersion: v1
19data:
20  player_initial_lives: "3"
21kind: ConfigMap
22metadata:
23  labels:
24    color: red
25    lfx-mentorship: kyverno
26  name: matched-cm-2
27  namespace: production
28---
29
30Mutation has been applied successfully.
31pass: 2, fail: 0, warn: 0, error: 0, skip: 0

Applying ValidatingPolicies

In this example, we will apply a ValidatingPolicy against two Deployment manifests: one that complies with the policy and one that violates it.

First, we define a ValidatingPolicy that ensures any Deployment has no more than two replicas.

Policy manifest (check-deployment-replicas.yaml):

 1apiVersion: policies.kyverno.io/v1alpha1
 2kind: ValidatingPolicy
 3metadata:
 4  name: check-deployment-replicas
 5spec:
 6  matchConstraints:
 7    resourceRules:
 8    - apiGroups:   ["apps"]
 9      apiVersions: ["v1"]
10      operations:  ["CREATE", "UPDATE"]
11      resources:   ["deployments"]
12  validations:
13    - expression: "object.spec.replicas <= 2"
14      message: "Deployment replicas must be less than or equal to 2"

Next, we have two Deployment manifests. The good-deployment is compliant with 2 replicas, while the bad-deployment is non-compliant with 3 replicas.

Resource manifest (deployments.yaml):

 1apiVersion: apps/v1
 2kind: Deployment
 3metadata:
 4  name: good-deployment
 5  labels:
 6    app: nginx
 7spec:
 8  replicas: 2
 9  selector:
10    matchLabels:
11      app: nginx
12  template:
13    metadata:
14      labels:
15        app: nginx
16    spec:
17      containers:
18      - name: nginx
19        image: nginx:latest
20---
21apiVersion: apps/v1
22kind: Deployment
23metadata:
24  name: bad-deployment
25  labels:
26    app: nginx
27spec:
28  replicas: 3
29  selector:
30    matchLabels:
31      app: nginx
32  template:
33    metadata:
34      labels:
35        app: nginx
36    spec:
37      containers:
38      - name: nginx
39        image: nginx:latest

Now, we use the kyverno apply command to test the policy against both resources.

1kyverno apply /path/to/check-deployment-replicas.yaml --resource /path/to/deployments.yaml --policy-report

The following output will be generated:

 1apiVersion: openreports.io/v1alpha1
 2kind: ClusterReport
 3metadata:
 4  creationTimestamp: null
 5  name: merged
 6results:
 7- message: Deployment replicas must be less than or equal 2
 8  policy: check-deployment-replicas
 9  properties:
10    process: background scan
11  resources:
12  - apiVersion: apps/v1
13    kind: Deployment
14    name: bad-deployment
15    namespace: default
16  result: fail
17  scored: true
18  source: KyvernoValidatingPolicy
19  timestamp:
20    nanos: 0
21    seconds: 1752755472
22- message: success
23  policy: check-deployment-replicas
24  properties:
25    process: background scan
26  resources:
27  - apiVersion: apps/v1
28    kind: Deployment
29    name: good-deployment
30    namespace: default
31  result: pass
32  scored: true
33  source: KyvernoValidatingPolicy
34  timestamp:
35    nanos: 0
36    seconds: 1752755472
37source: ""
38summary:
39  error: 0
40  fail: 1
41  pass: 1
42  skip: 0
43  warn: 0

In addition to testing local YAML files, you can use the kyverno apply command to validate policies against resources that are already running in a Kubernetes cluster. Instead of specifying resource files with the --resource flag, you can use the --cluster flag.

For example, to test the check-deployment-replicas policy against all Deployment resources in your currently active cluster, you would run:

1kyverno apply /path/to/check-deployment-replicas.yaml --cluster --policy-report

Many advanced policies need to look up the state of other resources in the cluster using Kyverno’s custom CEL functions like resource.Get(). When testing such policies locally with the kyverno apply command, the CLI cannot connect to the cluster to retrieve the required resources so you have to provide these resources as input via the --context-path flag.

This flag allows you to specify the resources that the policy will reference. The CLI will then use these resources to evaluate the policy.

This example demonstrates how to test a policy that validates an incoming Pod by checking its name against a value stored in a ConfigMap.

First, we define a ValidatingPolicy that uses resource.Get() to fetch a ConfigMap named policy-cm. The policy then validates that the incoming Pod’s name matches the name key in the ConfigMap’s data.

Policy manifest (check-pod-name-from-configmap.yaml):

 1apiVersion: policies.kyverno.io/v1alpha1
 2kind: ValidatingPolicy
 3metadata:
 4  name: check-pod-name-from-configmap
 5spec:
 6  matchConstraints:
 7    resourceRules:
 8    - apiGroups:   [""]
 9      apiVersions: ["v1"]
10      operations:  ["CREATE", "UPDATE"]
11      resources:   ["pods"]
12  variables:
13    # This variable uses a Kyverno CEL function to get a ConfigMap from the cluster.
14    - name: cm
15      expression: >-
16        resource.Get("v1", "configmaps", object.metadata.namespace, "policy-cm")
17  validations:
18    # This rule validates that the Pod's name matches the 'name' key in the ConfigMap's data.
19    - expression: >-
20        object.metadata.name == variables.cm.data.name

Next, we define two Pod manifests: good-pod, which should pass the validation, and bad-pod, which should fail.

Resource manifest (pods.yaml):

 1apiVersion: v1
 2kind: Pod
 3metadata:
 4  name: good-pod
 5spec:
 6  containers:
 7  - name: nginx
 8    image: nginx
 9---
10apiVersion: v1
11kind: Pod
12metadata:
13  name: bad-pod
14spec:
15  containers:
16  - name: nginx
17    image: nginx

Because the CLI cannot connect to a cluster to fetch the policy-cm ConfigMap, we must provide it in a context file. This file contains a mock ConfigMap that resource.Get() will use during local evaluation.

Context file (context.yaml):

 1apiVersion: cli.kyverno.io/v1alpha1
 2kind: Context
 3metadata:
 4  name: context
 5spec:
 6  # The resources defined here will be available to functions like resource.Get()
 7  resources:
 8  - apiVersion: v1
 9    kind: ConfigMap
10    metadata:
11      namespace: default
12      name: policy-cm
13    data:
14      # According to this, the valid pod name is 'good-pod'.
15      name: good-pod

Now, we can run the kyverno apply command, providing the policy, the resources, and the context file. We also use the -p (or --policy-report) flag to generate a ClusterReport detailing the results.

1kyverno apply /path/to/policy.yaml --resource /path/to/pods.yaml --context-file /path/to/context.yaml -p

The following output will be generated:

 1apiVersion: openreports.io/v1alpha1
 2kind: ClusterReport
 3metadata:
 4  creationTimestamp: null
 5  name: merged
 6results:
 7- message: success
 8  policy: check-pod-name-from-configmap
 9  properties:
10    process: background scan
11  resources:
12  - apiVersion: v1
13    kind: Pod
14    name: good-pod
15    namespace: default
16  result: pass
17  scored: true
18  source: KyvernoValidatingPolicy
19  timestamp:
20    nanos: 0
21    seconds: 1752756617
22- policy: check-pod-name-from-configmap
23  properties:
24    process: background scan
25  resources:
26  - apiVersion: v1
27    kind: Pod
28    name: bad-pod
29    namespace: default
30  result: fail
31  scored: true
32  source: KyvernoValidatingPolicy
33  timestamp:
34    nanos: 0
35    seconds: 1752756617
36source: ""
37summary:
38  error: 0
39  fail: 1
40  pass: 1
41  skip: 0
42  warn: 0

  • The good-pod resource resulted in a pass because its name matches the value in the ConfigMap provided by the context file.

  • The bad-pod resource resulted in a fail because its name does not match, and the report includes the validation error message from the policy.

When using the --cluster flag, the CLI connects to your active Kubernetes cluster, so a local context file is not needed. The resource.Get() function will fetch the live ConfigMap directly from the cluster so you have to ensure the ConfigMap and the Pod resources exist in your cluster before running the command.

1kyverno apply /path/to/check-pod-name-from-configmap.yaml --cluster --policy-report

In case of applying a ValidatingPolicy with a PolicyException, you can use the --exception flag to specify the exception manifest. The CLI will then apply the policy and the exception together.

In this example, we will test a policy that disallows hostPath volumes, but we will use a PolicyException to create an exemption for a specific Pod.

Policy manifest (disallow-host-path.yaml):

 1apiVersion: policies.kyverno.io/v1alpha1
 2kind: ValidatingPolicy
 3metadata:
 4  name: disallow-host-path
 5spec:
 6  matchConstraints:
 7    resourceRules:
 8    - apiGroups:   [""]
 9      apiVersions: ["v1"]
10      operations:  ["CREATE", "UPDATE"]
11      resources:   ["pods"]
12  validations:
13    - expression: "!has(object.spec.volumes) || object.spec.volumes.all(volume, !has(volume.hostPath))"
14      message: "HostPath volumes are forbidden. The field spec.volumes[*].hostPath must be unset."

Next, we define a Pod that clearly violates this policy by mounting a hostPath volume. Without an exception, this Pod would be blocked.

Resource manifest (pod-with-hostpath.yaml):

 1apiVersion: v1
 2kind: Pod
 3metadata:
 4  name: pod-with-hostpath
 5spec:
 6  containers:
 7  - name: nginx
 8    image: nginx
 9  volumes:
10  - name: udev
11    hostPath:
12      path: /etc/udev

Now, we create a PolicyException to exempt our specific Pod from this policy. The exception matches the Pod by name and references the disallow-host-path policy.

Policy Exception manifest (exception.yaml):

 1apiVersion: policies.kyverno.io/v1alpha1
 2kind: PolicyException
 3metadata:
 4  name: exempt-hostpath-pod
 5spec:
 6  policyRefs:
 7  - name: disallow-host-path
 8    kind: ValidatingPolicy
 9  matchConditions:
10    - name: "skip-pod-by-name"
11      expression: "object.metadata.name == 'pod-with-hostpath'"

Now, we use the kyverno apply command, providing the policy, the resource, and the exception using the --exception flag. We will also use -p to generate a detailed report.

1kyverno apply policy.yaml --resource resource.yaml --exception exception.yaml -p

The following output will be generated:

 1apiVersion: openreports.io/v1alpha1
 2kind: ClusterReport
 3metadata:
 4  creationTimestamp: null
 5  name: merged
 6results:
 7- message: 'rule is skipped due to policy exception: exempt-hostpath-pod'
 8  policy: disallow-host-path
 9  properties:
10    exceptions: exempt-hostpath-pod
11    process: background scan
12  resources:
13  - apiVersion: v1
14    kind: Pod
15    name: pod-with-hostpath
16    namespace: default
17  result: skip
18  rule: exception
19  scored: true
20  source: KyvernoValidatingPolicy
21  timestamp:
22    nanos: 0
23    seconds: 1752759828
24source: ""
25summary:
26  error: 0
27  fail: 0
28  pass: 0
29  skip: 1
30  warn: 0

The output confirms that the PolicyException worked as intended:

  • result: skip: The policy rule was not enforced on the resource.

  • properties.exceptions: exempt-hostpath-pod: The report explicitly names the PolicyException responsible for the skip.

  • summary.skip: 1: The final count reflects that one rule was skipped.


Last modified July 25, 2025 at 2:02 AM PST: fix broken links (#1617) (ea18fe1)