I've been searching for a while, but I'm pretty new to kustomize. It's taken me a while to get my head around the concept of overlays etc.

I'm trying to use a kustomization file to mount an existing secret into the pod. I can't do it in the deployment because it's a single deployment with 3 different versions of the deployment being handled by kustomize. Each needs a different secret mounting.

So the obvious answer would be to mount the secret as a volume using either a kustomize file in the base or overlay.

I've found information on generating a secret with kustomize, but the secret already exists and is passed in as a kubernetes secret elsewhere.

So to summarize...

base/
├─ kustomization.yaml
├─ statefulset.yaml
├─ service.yaml
├─ instance1/
│  ├─ kustomization.yaml
├─ instance2/
│  ├─ kustomization.yaml
├─ instance3/
│  ├─ kustomization.yaml

So I'm looking to handle the mounting of the secret to a volume in the instance locations, because the secret will be different for instance 1,2 & 3.

Is this possible?

TIA

EDIT:

I've added a file for the secret (it's for certs hence being different for each instance).

base/
├─ kustomization.yaml
├─ statefulset.yaml
├─ service.yaml
├─ instance1/
│  ├─ kustomization.yaml
│  ├─ pki.yaml
├─ instance2/
│  ├─ kustomization.yaml
├─ instance3/
│  ├─ kustomization.yaml

My patch file (pki.yaml) looks like this:

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: de
spec:
  template:
    containers:
    - name: de
      volumeMounts:
        - mountPath: "/opt/de/pki"
          name: pki
          readOnly: true
      volumes:
        - name: pki
          secret:
            secretName: de_1_pki

Then in ./base/instance1/kustomization.yaml I have:

commonLabels:
  app: de-1
resources:
- ../base
nameSuffix: -1
images:
- newName: de-1
  name: de
patches:
  - pki.yaml

And for completeness my ./base/kustomization.yaml file:

kind: Kustomization
apiVersion: kustomize.config.k8s.io/v1beta1
commonLabels:
  app: de
  affinity: directory
resources:
- service.yaml
- statefulset.yaml

I'm getting an error when deploying the above. So before I dig too deep, just wondering if I'm barking up the right tree?