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:
Apply a policy to all matching resources in a cluster based on the current kubectl context:
The resources can also be passed from stdin:
Apply all cluster policies in the current cluster to all matching resources in a cluster based on the current kubectl context:
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 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:
Save the mutated resource to a directory:
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, and API call context data.
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:
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):
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 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 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 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):
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.
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
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
Policies that have their validationFailureAction 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.
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.
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
5spec:
6 validationFailureAction: Audit
7 rules:
8 - name: validate-resources
9 match:
10 any:
11 - resources:
12 kinds:
13 - Pod
14 validate:
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
Case 2: Apply a policy manifest to multiple resources in the cluster
Create the resources by first applying manifests resource1.yaml and resource2.yaml.
Case 3: Apply a policy manifest to all resources in the cluster
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
Case 5: Apply a policy manifest to all resources within the default Namespace
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 validationFailureAction: Enforce
7 background: false
8 rules:
9 - name: max-two-containers
10 match:
11 any:
12 - resources:
13 kinds:
14 - Pod
15 validate:
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/v2beta1
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
Applying ValidatingAdmissionPolicies
With the apply command, Kubernetes ValidatingAdmissionPolicies can be applied to resources as follows:
Policy manifest (check-deployment-replicas.yaml):
1apiVersion: admissionregistration.k8s.io/v1beta1
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:
The following output will be generated:
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/v1beta1
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/v1beta1
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:
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:
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.
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