Inject Sidecar Container

 1apiVersion: kyverno.io/v1
 2kind: ClusterPolicy
 3metadata:
 4  name: inject-sidecar
 5  annotations:
 6    policies.kyverno.io/title: Inject Sidecar Container
 7    policies.kyverno.io/category: Sample
 8    policies.kyverno.io/subject: Pod
 9    policies.kyverno.io/description: >-
10      The sidecar pattern is very common in Kubernetes whereby other applications can
11      insert components via tacit modification of a submitted resource. This is, for example,
12      often how service meshes and secrets applications are able to function transparently.
13      This policy injects a sidecar container, initContainer, and volume into Pods that match
14      an annotation called `vault.hashicorp.com/agent-inject: true`.       
15spec:
16  background: false
17  rules:
18  - name: inject-sidecar
19    match:
20      resources:
21        kinds:
22        - Deployment
23    mutate:
24      patchStrategicMerge:
25        spec:
26          template:
27            metadata:
28              annotations:
29                (vault.hashicorp.com/agent-inject): "true"
30            spec:
31              containers:
32              - name: vault-agent
33                image: vault:1.5.4
34                imagePullPolicy: IfNotPresent
35                volumeMounts:
36                - mountPath: /vault/secrets
37                  name: vault-secret
38              initContainers:
39              - name: vault-agent-init
40                image: vault:1.5.4
41                imagePullPolicy: IfNotPresent
42                volumeMounts:
43                - mountPath: /vault/secrets
44                  name: vault-secret
45              volumes:
46              - name: vault-secret
47                emptyDir:
48                  medium: Memory
49