Restrict Pod Count per Node

 1apiVersion: kyverno.io/v1
 2kind: ClusterPolicy
 3metadata:
 4  name: restrict-pod-count
 5  annotations:
 6    policies.kyverno.io/title: Restrict Pod Count per Node
 7    policies.kyverno.io/category: Sample
 8    policies.kyverno.io/severity: medium
 9    policies.kyverno.io/subject: Pod
10    policies.kyverno.io/minversion: 1.6.0
11    policies.kyverno.io/description: >-
12      Sometimes Kubernetes Nodes may have a maximum number of Pods they can accommodate due to
13      resources outside CPU and memory such as licensing, or in some
14      development cases. This policy restricts Pod count on a Node named `minikube` to be no more than 10.
15    # pod-policies.kyverno.io/autogen-controllers: none
16spec:
17  validationFailureAction: Audit
18  background: false
19  rules:
20    - name: restrict-pod-count
21      match:
22        any:
23        - resources:
24            kinds:
25              - Pod
26      context:
27        - name: podcounts
28          apiCall:
29            urlPath: "/api/v1/pods"
30            jmesPath: "items[?spec.nodeName=='minikube'] | length(@)"
31      preconditions:
32        any:
33        - key: "{{ request.operation || 'BACKGROUND' }}"
34          operator: Equals
35          value: "CREATE"
36      validate:
37        message: "A maximum of 10 Pods are allowed on the Node `minikube`"
38        deny:
39          conditions:
40            any:
41            - key: "{{ podcounts }}"
42              operator: GreaterThan
43              value: 10