config/environment_variables/kustomization.yaml

# This configMap is only used to pass environment variables to Kustomize
configMapGenerator:
- name: environment
  envs:
  - environment.env

# Disable the name suffix hash, so `vars` can look for the correct configMap name
generatorOptions:
  disableNameSuffixHash: true

vars:
- name: EXCEPTION_CIDRS
  objref:
    kind: ConfigMap
    name: environment
    apiVersion: v1
  fieldref:
    fieldpath: data.EXCEPTION_CIDRS