Background Scans
Periodically reapply policies to existing resources for reporting.
Reporting
View and audit Kyverno policy results with reports.
Policy reports are Kubernetes Custom Resources, generated and managed automatically by Kyverno, which contain the results of applying matching Kubernetes resources to Kyverno ClusterPolicy or Policy resources. They are created for validate and verifyImages rules when a resource is matched by one or more rules according to the policy definition. If resources violate multiple rules, there will be multiple entries. When resources are deleted, their entry will be removed from the report. Reports, therefore, always represent the current state of the cluster and do not record historical information.
For example, if a validate policy in Audit mode exists containing a single rule which requires that all resources set the label team and a user creates a Pod which does not set the team label, Kyverno will allow the Pod’s creation but record it as a fail result in a policy report due to the Pod being in violation of the policy and rule. Policies configured with spec.validationFailureAction: Enforce immediately block violating resources and results will only be reported for pass evaluations. Policy reports are an ideal way to observe the impact a Kyverno policy may have in a cluster without causing disruption. The insights gained from these policy reports may be used to provide valuable feedback to both users/developers so they may take appropriate action to bring offending resources into alignment, and to policy authors or cluster operators to help them refine policies prior to changing them to Enforce mode. Because reports are decoupled from policies, standard Kubernetes RBAC can then be applied to separate those who can see and manipulate policies from those who can view reports.
Policy reports are created based on two different triggers: an admission event (a CREATE, UPDATE, or DELETE action performed against a resource) or the result of a background scan discovering existing resources. Policy reports, like Kyverno policies, have both Namespaced and cluster-scoped variants; a PolicyReport is a Namespaced resource while a ClusterPolicyReport is a cluster-scoped resource. Reports are stored in the cluster on a per resource basis. Every namespaced resource will (eventually) have an associated PolicyReport and every clustered resource will (eventually) have an associated ClusterPolicyReport.
Kyverno uses a standard and open format published by the Kubernetes Policy working group which proposes a common policy report format across Kubernetes tools. Below is an example of a PolicyReport generated for a Pod which shows passing and failed rules.
1apiVersion: wgpolicyk8s.io/v1alpha2
2kind: PolicyReport
3metadata:
4 creationTimestamp: "2023-12-06T13:19:03Z"
5 generation: 2
6 labels:
7 app.kubernetes.io/managed-by: kyverno
8 name: 487df031-11d8-4ab4-b089-dfc0db1e533e
9 namespace: kube-system
10 ownerReferences:
11 - apiVersion: v1
12 kind: Pod
13 name: kube-apiserver-kind-control-plane
14 uid: 487df031-11d8-4ab4-b089-dfc0db1e533e
15 resourceVersion: "720507"
16 uid: 0ec04a57-4c3d-492d-9278-951cd1929fe3
17results:
18- category: Pod Security Standards (Baseline)
19 message: validation rule 'adding-capabilities' passed.
20 policy: disallow-capabilities
21 result: pass
22 rule: adding-capabilities
23 scored: true
24 severity: medium
25 source: kyverno
26 timestamp:
27 nanos: 0
28 seconds: 1701868762
29- category: Pod Security Standards (Baseline)
30 message: 'validation error: Sharing the host namespaces is disallowed. The fields
31 spec.hostNetwork, spec.hostIPC, and spec.hostPID must be unset or set to `false`.
32 rule host-namespaces failed at path /spec/hostNetwork/'
33 policy: disallow-host-namespaces
34 result: fail
35 rule: host-namespaces
36 scored: true
37 severity: medium
38 source: kyverno
39 timestamp:
40 nanos: 0
41 seconds: 1701868762
42# ...
43scope:
44 apiVersion: v1
45 kind: Pod
46 name: kube-apiserver-kind-control-plane
47 namespace: kube-system
48 uid: 487df031-11d8-4ab4-b089-dfc0db1e533e
49summary:
50 error: 0
51 fail: 2
52 pass: 10
53 skip: 0
54 warn: 0
The report’s contents can be found under the results[] object in which it displays a number of fields including the resource that was matched against the rule in the parent policy.
Note
Policy reports show policy results for current resources in the cluster only. For information on resources that were blocked during admission controls, use the policy rule execution metric or inspect Kubernetes Events on the corresponding Kyverno policy. APod/exec subresource is not capable of producing an entry in a policy report due to API limitations.Policy reports have a few configuration options available. For details, see the container flags section.
Note
Policy reports created from background scans are not subject to the configuration of a Namespace selector defined in the Kyverno ConfigMap.Note
To configure Kyverno to generate reports for Kubernetes ValidatingAdmissionPolicies enable the--validatingAdmissionPolicyReports flag in the reports controller.Report result logic
Entries in a policy report contain a result field which can be either pass, skip, warn, error, or fail.
| Result | Description |
|---|---|
| pass | The resource was applicable to a rule and the pattern passed evaluation. |
| skip | Preconditions were not satisfied (if applicable) in a rule, or an applicable PolicyException exists and so further processing was not performed. |
| fail | The resource failed the pattern evaluation. |
| warn | The annotation policies.kyverno.io/scored has been set to "false" in the policy converting otherwise fail results to warn. |
| error | Variable substitution failed outside of preconditions and elsewhere in the rule (ex., in the pattern). |
Viewing policy report summaries
You can view a summary of the Namespaced policy reports using the following command:
1kubectl get policyreport -A
For example, below are the policy reports found in the kube-system namespace of a small test cluster created with kind.
1$ kubectl get polr -n kube-system -o wide
2NAME KIND NAME PASS FAIL WARN ERROR SKIP AGE
3049a4ec1-32a5-4417-9184-1a59cfaa1ca6 DaemonSet kindnet 9 3 0 0 0 16m
4049d2cca-c30f-4f26-a70a-dfcc2cc5f433 DaemonSet kube-proxy 9 3 0 0 0 16m
51d491ec4-ca84-4b3a-960a-a2aefa3219ba Pod kube-controller-manager-kind-control-plane 10 2 0 0 0 16m
634fa05b8-40cc-4bd3-836e-077abf4c126e Pod kindnet-qtq54 9 3 0 0 0 16m
73997d5d0-363a-4820-8768-4be3788b3968 Pod kube-proxy-tcgcz 9 3 0 0 0 16m
84434c0ac-e27f-41eb-b4c2-b1a7aca8056a ReplicaSet coredns-5dd5756b68 12 0 0 0 0 16m
9487df031-11d8-4ab4-b089-dfc0db1e533e Pod kube-apiserver-kind-control-plane 10 2 0 0 0 16m
10553c0601-b995-4ed8-a36b-11e7cb38893b Pod kube-proxy-jdsck 9 3 0 0 0 16m
1189044d72-8a1e-4af0-877b-9be727dc3ec4 Pod kindnet-7rrns 9 3 0 0 0 16m
129eb8c5c0-fe5c-4c7d-96c3-3ff65c361f4f Pod etcd-kind-control-plane 10 2 0 0 0 16m
13b7968d37-4337-4756-bfe8-3c111f7a7356 Pod kube-proxy-ncvxk 9 3 0 0 0 16m
14cc894ef1-6a45-44e0-99f6-3765a59088e7 Pod kube-scheduler-kind-control-plane 10 2 0 0 0 16m
15cf538bcc-4752-45d4-9712-480c425dc8d3 Pod kindnet-c8fv6 9 3 0 0 0 16m
16d9ea5169-17a7-458d-a971-09028a73cddd Pod coredns-5dd5756b68-z5whj 12 0 0 0 0 16m
17e23946aa-17c3-4b96-b72b-eb7fd72eba62 Deployment coredns 12 0 0 0 0 16m
18e666a741-c9cf-499c-a9c7-b8e0c600239a Pod kindnet-2rkgr 9 3 0 0 0 16m
19e6f5aa6a-74e0-4c30-bb2b-1a6ee046e5ad Pod coredns-5dd5756b68-tnv25 12 0 0 0 0 16m
20fd2aa944-3fc7-42b0-a6c0-1304e0aa473f Pod kube-proxy-p4x82 9 3 0 0 0 16m
Similarly, you can view the cluster-wide report using:
1kubectl get clusterpolicyreport
Tip
Note that the name of the report is mostly random. Add-o wide to show additional information that will help identify the resource associated with the report.Tip
For a graphical view of Policy Reports, check out Policy Reporter.Viewing policy violations
Since the report provides information on all rule and resource execution, returning only select entries requires a filter expression.
Policy reports can be inspected using either kubectl describe or kubectl get. For example, here is a command, requiring yq, to view only failures for the (Namespaced) report 1d491ec4-ca84-4b3a-960a-a2aefa3219ba:
1kubectl get polr 1d491ec4-ca84-4b3a-960a-a2aefa3219ba -o jsonpath='{.results[?(@.result=="fail")]}' | yq -p json -
1category: Pod Security Standards (Baseline)
2message: 'validation error: Privileged mode is disallowed. The fields spec.containers[*].securityContext.privileged and spec.initContainers[*].securityContext.privileged must be unset or set to `false`. . rule privileged-containers failed at path /spec/containers/0/securityContext/privileged/'
3policy: disallow-privileged-containers
4result: fail
5rule: privileged-containers
6scored: true
7severity: medium
8source: kyverno
9timestamp:
10 nanos: 0
11 seconds: 1.666094801e+09
12---
13category: Pod Security Standards (Baseline)
14message: 'validation error: Privileged mode is disallowed. The fields spec.containers[*].securityContext.privileged and spec.initContainers[*].securityContext.privileged must be unset or set to `false`. . rule privileged-containers failed at path /spec/containers/0/securityContext/privileged/'
15policy: disallow-privileged-containers
16result: fail
17rule: privileged-containers
18scored: true
19severity: medium
20source: kyverno
21timestamp:
22 nanos: 0
23 seconds: 1.666095335e+09
Report internals
The PolicyReport and ClusterPolicyReport are the final resources composed of matching resources as determined by Kyverno Policy and ClusterPolicy objects, however these reports are built of four intermediary resources. For matching resources which were caught during admission mode, AdmissionReport and ClusterAdmissionReport resources are created. For results of background processing, BackgroundScanReport and ClusterBackgroundScanReport resources are created. An example of a ClusterAdmissionReport is shown below.
1apiVersion: kyverno.io/v1alpha2
2kind: ClusterAdmissionReport
3metadata:
4 creationTimestamp: "2022-10-18T13:15:09Z"
5 generation: 1
6 labels:
7 app.kubernetes.io/managed-by: kyverno
8 audit.kyverno.io/resource.hash: a7ec5160f220c5b83c26b5c8f7dc35b6
9 audit.kyverno.io/resource.uid: 61946422-14ba-4aa2-94b4-229d38446381
10 cpol.kyverno.io/require-ns-labels: "4773"
11 name: c0cc7337-9bcd-4d53-abb2-93f7f5555216
12 resourceVersion: "4986"
13 uid: 10babc6c-9e6e-4386-abed-c13f50091523
14spec:
15 owner:
16 apiVersion: v1
17 kind: Namespace
18 name: testing
19 uid: 61946422-14ba-4aa2-94b4-229d38446381
20 results:
21 - message: 'validation error: The label `thisshouldntexist` is required. rule check-for-labels-on-namespace
22 failed at path /metadata/labels/thisshouldntexist/'
23 policy: require-ns-labels
24 result: fail
25 rule: check-for-labels-on-namespace
26 scored: true
27 source: kyverno
28 timestamp:
29 nanos: 0
30 seconds: 1666098909
31 summary:
32 error: 0
33 fail: 1
34 pass: 0
35 skip: 0
36 warn: 0
These intermediary resources have the same basic contents as a policy report and are used internally by Kyverno to build the final policy report. Kyverno will merge these results automatically into the appropriate policy report and there is no manual interaction typically required.
For more details on the internal reporting processes, see the developer docs here.
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Last modified December 19, 2023 at 6:19 PM PST: add validatingAdmissionPolicyReports flag (cherry-pick #1075) (#1076) (5ba156b)