Exclude Namespaces Dynamically

 1apiVersion: kyverno.io/v1
 2kind: ClusterPolicy
 3metadata:
 4  name: exclude-namespaces-example
 5  annotations:
 6    policies.kyverno.io/title: Exclude Namespaces Dynamically
 7    policies.kyverno.io/category: Sample
 8    policies.kyverno.io/severity: medium
 9    policies.kyverno.io/subject: Namespace, Pod
10    policies.kyverno.io/description: >-
11      It's common where policy lookups need to consider a mapping to many possible values rather than a
12      static mapping. This is a sample which demonstrates how to dynamically look up an allow list of Namespaces from a ConfigMap
13      where the ConfigMap stores an array of strings. This policy validates that any Pods created
14      outside of the list of Namespaces have the label `foo` applied.      
15spec:
16  validationFailureAction: audit
17  background: true
18  rules:
19  - name: exclude-namespaces-dynamically
20    context:
21      - name: namespacefilters
22        # The source ConfigMap should contain an array of strings in either YAML block scalars
23        # (Kyverno 1.3.5+) or JSON-encoded format.
24        configMap:
25          name: namespace-filters
26          namespace: default
27    match:
28      resources:
29        kinds:
30        - Pod
31    preconditions:
32      all:
33      - key: "{{request.object.metadata.namespace}}"
34        operator: NotIn
35        value: "{{namespacefilters.data.exclude}}"
36    validate:
37      message: >
38        Creating Pods in the {{request.namespace}} namespace,
39        which is not in the excluded list of namespaces {{ namespacefilters.data.exclude }},
40        is forbidden unless it carries the label `foo`.        
41      pattern:
42        metadata:
43          labels:
44            foo: "*"