Kyverno CLI

Apply and test policies outside a cluster.

The Kyverno Command Line Interface (CLI) is designed to validate and test policy behavior to resources prior to adding them to a cluster. The CLI can be used in CI/CD pipelines to assist with the resource authoring process to ensure they conform to standards prior to them being deployed. It can be used as a kubectl plugin or as a standalone CLI. The CLI, although composed of the same Kyverno codebase, is a purpose-built binary available via multiple installation methods but is distinct from the Kyverno container image which runs as a Pod in a target Kubernetes cluster.

Building and Installing the CLI

Install via Krew

You can use Krew to install the Kyverno CLI:

1# Install Kyverno CLI using kubectl krew plugin manager
2kubectl krew install kyverno
3
4# test the Kyverno CLI
5kubectl kyverno version

Install via AUR (archlinux)

You can install the Kyverno CLI via your favorite AUR helper (e.g. yay)

1yay -S kyverno-git

Install via Homebrew

The Kyverno CLI can also be installed with Homebrew as a formula.

1brew install kyverno

Manual Binary Installation

The Kyverno CLI may also be installed by manually downloading the compiled binary available on the releases page. An example of installing the Kyverno CLI v1.7.2 on a Linux x86_64 system is shown below.

1curl -LO https://github.com/kyverno/kyverno/releases/download/v1.7.2/kyverno-cli_v1.7.2_linux_x86_64.tar.gz
2tar -xvf kyverno-cli_v1.7.2_linux_x86_64.tar.gz
3sudo cp kyverno /usr/local/bin/

Building the CLI from source

You can also build the CLI binary from the Git repository (requires Go).

1git clone https://github.com/kyverno/kyverno
2cd kyverno
3make build-cli
4mv ./cmd/cli/kubectl-kyverno/kyverno /usr/local/bin/kyverno

CLI Commands

When using the Kyverno CLI with kustomize, it is recommended to use the “standalone” version as opposed to the version embedded inside kubectl.

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.

Note

Kyverno CLI apply 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 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 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/

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 (Kyverno 1.3.6), and API call context data (Kyverno 1.3.6).

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.

Note

When passing ConfigMap array data into the values file, the data must be formatted as JSON outlined here.

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:

 1policies:
 2  - name: <policy1 name>
 3    rules:
 4    - name: <rule1 name>
 5      values:
 6        <context variable1 in policy1 rule1>: <value>
 7        <context variable2 in policy1 rule1>: <value>
 8    - name: <rule2 name>
 9      values:
10        <context variable1 in policy1 rule2>: <value>
11        <context variable2 in policy1 rule2>: <value>
12    resources:
13    - name: <resource1 name>
14      values:
15        <variable1 in policy1>: <value>
16        <variable2 in policy1>: <value>
17    - name: <resource2 name>
18      values:
19        <variable1 in policy1>: <value>
20        <variable2 in policy1>: <value>
21namespaceSelector:
22- name: <namespace1 name>
23  labels:
24    <label key>: <label value>
25- name: <namespace2 name>
26  labels:
27    <label key>: <label value>

Format of user_info.yaml:

1clusterRoles:
2- admin
3userInfo:
4  username: molybdenum@somecorp.com

Example:

Policy manifest (add_network_policy.yaml):

 1apiVersion: kyverno.io/v1
 2kind: ClusterPolicy
 3metadata:
 4  name: add-networkpolicy
 5  annotations:
 6    policies.kyverno.io/category: Workload Management
 7    policies.kyverno.io/description: By default, Kubernetes allows communications across
 8      all pods within a cluster. Network policies and, a CNI that supports network policies,
 9      must be used to restrict communications. A default NetworkPolicy should be configured
10      for each namespace to default deny all ingress traffic to the pods in the namespace.
11      Application teams can then configure additional NetworkPolicy resources to allow
12      desired traffic to application pods from select sources.
13spec:
14  rules:
15  - name: default-deny-ingress
16    match:
17      any:
18      - resources:
19          kinds:
20          - Namespace
21      clusterRoles:
22      - cluster-admin
23    generate:
24      kind: NetworkPolicy
25      name: default-deny-ingress
26      namespace: "{{request.object.metadata.name}}"
27      synchronize: true
28      data:
29        spec:
30          # select all pods in the namespace
31          podSelector: {}
32          policyTypes:
33          - 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):

1policies:
2  - name: add-networkpolicy
3    resources:
4      - name: devtest
5        values:
6          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:

 1policies:
 2  - name: <policy1 name>
 3    resources:
 4      - name: <resource1 name>
 5        values:
 6          <variable1 in policy1>: <value>
 7          <variable2 in policy1>: <value>
 8      - name: <resource2 name>
 9        values:
10          <variable1 in policy1>: <value>
11          <variable2 in policy1>: <value>
12  - name: <policy2 name>
13    resources:
14      - name: <resource1 name>
15        values:
16          <variable1 in policy2>: <value>
17          <variable2 in policy2>: <value>
18      - name: <resource2 name>
19        values:
20          <variable1 in policy2>: <value>
21          <variable2 in policy2>: <value>
22globalValues:
23  <global variable1>: <value>
24  <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  validationFailureAction: enforce
 7  background: false
 8  rules:
 9    - name: validate-mode
10      match:
11        any:
12        - resources:
13            kinds:
14              - Pod
15      validate:
16        message: "The value {{ request.mode }} for val1 is not equal to 'dev'."
17        deny:
18          conditions:
19            - key: "{{ request.mode }}"
20              operator: NotEquals
21              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):

1policies:
2  - name: cm-globalval-example
3    resources:
4      - name: test-global-prod
5        values:
6          request.mode: prod
7globalValues:
8  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:

1namespaceSelector:
2  - name: <namespace1 name>
3    labels:
4      <namespace label key>: <namespace label value>
5  - name: <namespace2 name>
6    labels:
7      <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  validationFailureAction: audit
 7  background: true
 8  rules:
 9    - name: validate-name
10      match:
11        any:
12        - resources:
13            kinds:
14              - Pod
15          namespaceSelector:
16            matchExpressions:
17            - key: foo.com/managed-state
18              operator: In
19              values:
20              - managed
21      validate:
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):

1namespaceSelector:
2  - name: test1
3    labels:
4      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  validationFailureAction: enforce
 9  background: false
10  rules:
11    - name: example-configmap-lookup
12      context:
13      - name: dictionary
14        configMap:
15          name: mycmap
16          namespace: default
17      match:
18        any:
19        - resources:
20            kinds:
21            - Pod
22      mutate:
23        patchStrategicMerge:
24          metadata:
25            labels:
26              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

1policies:
2  - name: cm-variable-example
3    rules:
4      - name: example-configmap-lookup
5        values:
6          dictionary.data.env: dev1

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.

Policy	Resource	Cluster	Namespace	Interpretation
policy.yaml	-r resource.yaml	false		Apply policy from `policy.yaml` to the resources specified in `resource.yaml`
policy.yaml	-r resourceName	true		Apply policy from `policy.yaml` to the resource with a given name in the cluster
policy.yaml		true		Apply policy from policy.yaml to all the resources in the cluster
policy.yaml	-r resourceName	true	-n=namespaceName	Apply policy from `policy.yaml` to the resource with a given name in a specific Namespace
policy.yaml		true	-n=namespaceName	Apply 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
 5  annotations:
 6    policies.kyverno.io/category: Workload Management
 7    policies.kyverno.io/description: >-
 8      As application workloads share cluster resources, it is important to limit resources
 9      requested and consumed by each pod. It is recommended to require 'resources.requests'
10      and 'resources.limits' per pod. If a namespace level request or limit is specified,
11      defaults are automatically applied to each pod based on the 'LimitRange' configuration.      
12spec:
13  validationFailureAction: audit
14  rules:
15  - name: validate-resources
16    match:
17      any:
18      - resources:
19          kinds:
20          - Pod
21    validate:
22      message: "CPU and memory resource requests and limits are required"
23      pattern:
24        spec:
25          containers:
26          - resources:
27              requests:
28                memory: "?*"
29                cpu: "?*"
30              limits:
31                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

Test

The test command is used to test a given set of resources against one or more policies to check desired results, declared in advance in a separate test manifest file, against the actual results. test is useful when you wish to declare what your expected results should be by defining the intent which then assists with locating discrepancies should those results change.

test works by scanning a given location, which can be either a Git repository or local folder, and executing the tests defined within. The rule types validate, mutate, and generate are currently supported. The command recursively looks for YAML files with policy test declarations (described below) with a specified file name and then executes those tests. All files applicable to the same test must be co-located. Directory recursion is supported. test supports the auto-gen feature making it possible to test, for example, Deployment resources against a Pod policy.

test will search for a file named kyverno-test.yaml and, if found, will execute the tests within.

In each test, there are four desired results which can be tested for. If the actual result of the test, once executed, matches the desired result as defined in the test manifest, it will be scored as a pass in the command output. For example, if the specified result of a given test of a resource against a policy is declared to be a pass and the actual result when tested is also a pass, the command output will show as pass. If the actual result was instead a skip, the command output will show as fail because the two results do not agree. The following are the desired results which can be specified in a test manifest.

pass: The resource passes the policy definition. For validate rules which are written with a deny statement, this will not be a possible result. mutate and generate rules can declare a pass.
skip: The resource does not meet either the match or exclude block, or does not pass the preconditions statements. For validate rules which are written with a deny statement, this is a possible result. If a rule contains certain conditional anchors which are not satisfied, the result may also be scored as a skip.
fail: The resource does not pass the policy definition. Typically used for validate rules with pattern-style policy definitions.
warn: Setting the annotation policies.kyverno.io/scored to "false" on a resource or policy which would otherwise fail will be considered a warn.

For help with the test command, pass the -h flag for extensive output including usage, flags, and sample manifests.

Note

The Kyverno CLI via the test command does not embed the Kubernetes control plane components and therefore is not able to perform the types of initial mutations subjected to a resource as part of an in-cluster creation flow. Take care to ensure the manifests you test account for these modifications.

Test File Structures

The test declaration file format of kyverno-test.yaml must be of the following format. In order to quickly generate a sample manifest which you can populate with your specified inputs, use either the --manifest-mutate or --manifest-validate command and output the result to a kyverno-test.yaml file.

 1name: mytests
 2policies:
 3  - <path/to/policy.yaml>
 4  - <path/to/policy.yaml>
 5resources:
 6  - <path/to/resource.yaml>
 7  - <path/to/resource.yaml>
 8variables: variables.yaml # optional file for declaring variables. see below for example.
 9userinfo: user_info.yaml # optional file for declaring admission request information (roles, cluster roles and subjects). see below for example.
10results:
11- policy: <name>
12  rule: <name>
13  resource: <name>
14  resources: # optional, primarily for `validate` rules. One of either `resource` or `resources[]` must be specified. Use `resources[]` when a number of different resources should all share the same test result.
15  - <name_1>
16  - <name_2>
17  namespace: <name> # when testing for a resource in a specific Namespace
18  patchedResource: <file_name.yaml> # when testing a mutate rule this field is required.
19  generatedResource: <file_name.yaml> # when testing a generate rule this field is required.
20  kind: <kind>
21  result: pass

The test declaration consists of the following parts:

The policies element which lists one or more policies to be applied.
The resources element which lists one or more resources to which the policies are applied.
The variables element which defines a file in which variables and their values are stored for use in the policy test. Optional depending on policy content.
The userinfo element which declares admission request data for subjects and roles. Optional depending on policy content.
The results element which declares the expected results. Depending on the type of rule being tested, this section may vary.

If needing to pass variables, such as those from external data sources like context variables built from API calls or others, a variables.yaml file can be defined with the same format as accepted with the apply command. If a variable needs to contain an array of strings, it must be formatted as JSON encoded. Like with the apply command, variables that begin with request.object normally do not need to be specified in the variables file as these will be sourced from the resource. Policies which trigger based upon request.operation equaling CREATE do not need a variables file. The CLI will assume a value of CREATE if no variable for request.operation is defined.

 1policies:
 2  - name: exclude-namespaces-example
 3    rules:
 4      - name: exclude-namespaces-dynamically
 5        values:
 6          namespacefilters.data.exclude: asdf
 7    resources:
 8      - name: nonroot-pod
 9        values:
10          namespacefilters.data.exclude: foo
11      - name: root-pod
12        values:
13          namespacefilters.data.exclude: "[\"cluster-admin\", \"cluster-operator\", \"tenant-admin\"]"

A variables file may also optionally specify global variable values without the need to name specific rules or resources avoiding repetition for the same variable and same value.

1globalValues:
2  request.operation: UPDATE

If policies use a namespaceSelector, these can also be specified in the variables file.

1namespaceSelector:
2  - name: test1
3    labels:
4      foo.com/managed-state: managed

The user can also declare a user_info.yaml file that can be used to pass admission request information such as roles, cluster roles, and subjects.

1clusterRoles:
2- admin
3userInfo:
4  username: someone@somecorp.com

Test Against Local Files

Test a set of local files in the working directory.

1kyverno test .

Test a set of local files by specifying the directory.

1kyverno test /path/to/folderContainingTestYamls

Test Against Git Repositories

Test an entire Git repository by specifying the branch name within the repo URL. If branch is not specified, main will be used as a default.

1kyverno test https://github.com/kyverno/policies/release-1.6

Test a specific directory of the repository by specifying the directory within repo URL and the branch with the --git-branch or -b flag. Even if testing against main, when using a directory in the URL of the repo requires passing the --git-branch or -b flag.

1kyverno test https://github.com/kyverno/policies/pod-security/restricted -b release-1.6

Use the -f flag to set a custom file name which includes test cases. By default, test will search for a file called kyverno-test.yaml.

Testing Policies with Image Registry Access

For policies which require image registry access to set context variables, those variables may be sourced from a variables file (defined below) or from a “live” registry by passing the --registry flag.

Test Subset of Resources

In some cases, you may wish to only test a subset of policy, rules, and/ resource combination rather than all those defined in a test manifest. Use the --test-case-selector flag to specify the exact tests you wish to execute.

1kyverno test . --test-case-selector "policy=add-default-resources, rule=add-default-requests, resource=nginx-demo2"

Examples

The test command executes a test declaration by applying the policies to the resources and comparing the actual results with the desired/expected results. The test passes if the actual results match the expected results.

Below is an example of testing a policy containing two validate rules against the same resource where each is supposed to pass the policy.

Policy manifest (disallow_latest_tag.yaml):

 1apiVersion: kyverno.io/v1
 2kind: ClusterPolicy
 3metadata:
 4  name: disallow-latest-tag
 5  annotations:
 6    policies.kyverno.io/category: Best Practices
 7    policies.kyverno.io/description: >-
 8      The ':latest' tag is mutable and can lead to unexpected errors if the 
 9      image changes. A best practice is to use an immutable tag that maps to 
10      a specific version of an application pod.      
11spec:
12  validationFailureAction: audit
13  rules:
14  - name: require-image-tag
15    match:
16      any:
17      - resources:
18          kinds:
19          - Pod
20      clusterRoles:
21      - cluster-admin
22    validate:
23      message: "An image tag is required."  
24      pattern:
25        spec:
26          containers:
27          - image: "*:*"
28  - name: validate-image-tag
29    match:
30      any:
31      - resources:
32          kinds:
33          - Pod
34    validate:
35      message: "Using a mutable image tag e.g. 'latest' is not allowed."
36      pattern:
37        spec:
38          containers:
39          - image: "!*:latest"

Resource manifest (resource.yaml):

 1apiVersion: v1
 2kind: Pod
 3metadata:
 4  name: myapp-pod
 5  labels:
 6    app: myapp
 7spec: 
 8  containers:
 9  - name: nginx
10    image: nginx:1.12

Test manifest (kyverno-test.yaml):

 1name: disallow_latest_tag
 2policies:
 3  - disallow_latest_tag.yaml
 4resources:
 5  - resource.yaml
 6results:
 7  - policy: disallow-latest-tag
 8    rule: require-image-tag
 9    resource: myapp-pod
10    kind: Pod
11    result: pass
12  - policy: disallow-latest-tag
13    rule: validate-image-tag
14    resource: myapp-pod
15    kind: Pod
16    result: pass

 1$ kyverno test .
 2
 3Executing disallow_latest_tag...
 4applying 1 policy to 1 resource... 
 5
 6│───│─────────────────────│────────────────────│───────────────────────│────────│
 7│ # │ POLICY              │ RULE               │ RESOURCE              │ RESULT │
 8│───│─────────────────────│────────────────────│───────────────────────│────────│
 9│ 1 │ disallow-latest-tag │ require-image-tag  │ default/Pod/myapp-pod │ Pass   │
10│ 2 │ disallow-latest-tag │ validate-image-tag │ default/Pod/myapp-pod │ Pass   │
11│───│─────────────────────│────────────────────│───────────────────────│────────│
12
13Test Summary: 2 tests passed and 0 tests failed

In the below case, a mutate policy which adds default resources to a Pod is being tested against two resources. Notice the addition of the patchedResource field in the results[] array, which is a requirement when testing mutate rules.

Policy manifest (add-default-resources.yaml):

 1apiVersion : kyverno.io/v1
 2kind: ClusterPolicy
 3metadata:
 4  name: add-default-resources
 5spec:
 6  background: false
 7  rules:
 8  - name: add-default-requests
 9    match:
10      any:
11      - resources:
12          kinds:
13          - Pod
14    preconditions:
15      any:
16      - key: "{{request.operation}}"
17        operator: In
18        value:
19        - CREATE
20        - UPDATE
21    mutate:
22      patchStrategicMerge:
23        spec:
24          containers:
25            - (name): "*"
26              resources:
27                requests:
28                  +(memory): "100Mi"
29                  +(cpu): "100m"

Resource manifest (resource.yaml):

 1apiVersion: v1
 2kind: Pod
 3metadata:
 4  name: nginx-demo1
 5spec:
 6  containers:
 7  - name: nginx
 8    image: nginx:1.14.2
 9---
10apiVersion: v1
11kind: Pod
12metadata:
13  name: nginx-demo2
14spec:
15  containers:
16  - name: nginx
17    image: nginx:latest
18    resources:
19      requests:
20        memory: "200Mi" 
21        cpu: "200m"

Variables manifest (values.yaml):

1policies:
2- name: add-default-resources
3  resources:
4  - name: nginx-demo1
5    values:
6      request.operation: CREATE
7  - name: nginx-demo2
8    values:
9      request.operation: UPDATE

Test manifest (kyverno-test.yaml):

 1name: add-default-resources
 2policies:
 3  - add-default-resources.yaml
 4resources:
 5  - resource.yaml
 6variables: values.yaml
 7results:
 8  - policy: add-default-resources
 9    rule: add-default-requests
10    resource: nginx-demo1
11    patchedResource: patchedResource1.yaml
12    kind: Pod
13    result: pass
14  - policy: add-default-resources
15    rule: add-default-requests
16    resource: nginx-demo2
17    patchedResource: patchedResource2.yaml
18    kind: Pod
19    result: skip

 1$ kyverno test .
 2
 3Executing add-default-resources...
 4applying 1 policy to 2 resources... 
 5
 6skipped mutate policy add-default-resources -> resource default/Pod/nginx-demo2
 7│───│───────────────────────│──────────────────────│─────────────────────────│────────│
 8│ # │ POLICY                │ RULE                 │ RESOURCE                │ RESULT │
 9│───│───────────────────────│──────────────────────│─────────────────────────│────────│
10│ 1 │ add-default-resources │ add-default-requests │ default/Pod/nginx-demo1 │ Pass   │
11│ 2 │ add-default-resources │ add-default-requests │ default/Pod/nginx-demo2 │ Pass   │
12│───│───────────────────────│──────────────────────│─────────────────────────│────────│
13
14Test Summary: 2 tests passed and 0 tests failed

In the following policy test, a generate policy rule is applied which generates a new resource from an existing resource present in resource.yaml. To test the generate policy, the addition of a generatedResource field in the results[] array is required which is used to test against the resource generated by the policy.

Policy manifest (add_network_policy.yaml):

 1apiVersion: kyverno.io/v1
 2kind: ClusterPolicy
 3metadata:
 4  name: add-networkpolicy
 5  annotations:
 6    policies.kyverno.io/title: Add Network Policy
 7    policies.kyverno.io/category: Multi-Tenancy
 8    policies.kyverno.io/subject: NetworkPolicy
 9    policies.kyverno.io/description: >-
10      By default, Kubernetes allows communications across all Pods within a cluster.
11      The NetworkPolicy resource and a CNI plug-in that supports NetworkPolicy must be used to restrict
12      communications. A default NetworkPolicy should be configured for each Namespace to
13      default deny all ingress and egress traffic to the Pods in the Namespace. Application
14      teams can then configure additional NetworkPolicy resources to allow desired traffic
15      to application Pods from select sources. This policy will create a new NetworkPolicy resource
16      named `default-deny` which will deny all traffic anytime a new Namespace is created.      
17spec:
18  rules:
19  - name: default-deny
20    match:
21      any:
22      - resources:
23          kinds:
24          - Namespace
25    generate:
26      apiVersion: networking.k8s.io/v1
27      kind: NetworkPolicy
28      name: default-deny
29      namespace: "{{request.object.metadata.name}}"
30      synchronize: true
31      data:
32        spec:
33          podSelector: {}
34          policyTypes:
35          - Ingress
36          - Egress

Resource manifest (resource.yaml):

1apiVersion: v1
2kind: Namespace
3metadata:
4  name: hello-world-namespace

Generated Resource (generatedResource.yaml):

 1apiVersion: networking.k8s.io/v1
 2kind: NetworkPolicy
 3metadata:
 4  name: default-deny
 5  namespace: hello-world-namespace
 6spec:
 7  podSelector: {}
 8  policyTypes:
 9  - Ingress
10  - Egress

Test manifest (kyverno-test.yaml):

 1name: deny-all-traffic
 2policies:
 3  - add_network_policy.yaml
 4resources:
 5  - resource.yaml
 6results:
 7  - policy: add-networkpolicy
 8    rule: default-deny
 9    resource: hello-world-namespace
10    generatedResource: generatedResource.yaml
11    kind: Namespace
12    result: pass

 1$ kyverno test .
 2Executing deny-all-traffic...
 3applying 1 policy to 1 resource... 
 4 
 5│───│───────────────────│──────────────│──────────────────────────────────│────────│
 6│ # │ POLICY            │ RULE         │ RESOURCE                         │ RESULT │
 7│───│───────────────────│──────────────│──────────────────────────────────│────────│
 8│ 1 │ add-networkpolicy │ default-deny │ /Namespace/hello-world-namespace │ Pass   │
 9│───│───────────────────│──────────────│──────────────────────────────────│────────│
10Test Summary: 1 tests passed and 0 tests failed

For many more examples of test cases, please see the kyverno/policies repository which strives to have test cases for all the sample policies which appear on the website.

Jp

The Kyverno CLI has a jp subcommand which makes it possible to test not only the custom filters endemic to Kyverno but also the full array of capabilities of JMESPath included in the jp tool itself here. By passing in either through stdin or a file, both for input JSON or YAML documents and expressions, the jp subcommand will evaluate any JMESPath expression and supply the output.

Example:

List available Kyverno custom JMESPath filters. Please refer to the JMESPath documentation page here for extensive details on each custom filter.

1$ kyverno jp -l
2add(any, any) any
3base64_decode(string) string
4base64_encode(string) string
5compare(string, string) bool
6<output abbreviated>

Test a custom JMESPath filter using stdin inputs.

1$ echo '{"foo": "BAR"}' | kyverno jp 'to_lower(foo)'
2"bar"

Test a custom JMESPath filter using an input JSON file. YAML files are also supported.

 1$ cat foo
 2{"bar": "this-is-a-dashed-string"}
 3
 4$ kyverno jp -f foo "split(bar, '-')"
 5[
 6  "this",
 7  "is",
 8  "a",
 9  "dashed",
10  "string"
11]

Test a custom JMESPath filter as well as an upstream JMESPath filter.

1$ kyverno jp -f foo "split(bar, '-') | length(@)"
25

Test a custom JMESPath filter using an expression from a file.

1$ cat add
2add(`1`,`2`)
3
4$ echo {} | kyverno jp -e add
53

Test upstream JMESPath functionality using an input JSON file and show cleaned output.

 1$ cat pod.json
 2{
 3  "apiVersion": "v1",
 4  "kind": "Pod",
 5  "metadata": {
 6    "name": "mypod",
 7    "namespace": "foo"
 8  },
 9  "spec": {
10    "containers": [
11      {
12        "name": "busybox",
13        "image": "busybox"
14      }
15    ]
16  }
17}
18
19$ kyverno jp -f pod.json 'spec.containers[0].name' -u
20busybox

For more specific information on writing JMESPath for use in Kyverno, see the JMESPath page.

Version

Prints the version of Kyverno CLI.

Example:

1$ kyverno version
2Version: 1.6.0
3Time: 2022-02-08T07:49:45Z
4Git commit ID: 5b4d4c266353981a559fe210b4e85100fa3bf397

Last modified October 20, 2022 at 7:48 AM PST: Doc updates (#657) (ddaf374)