Usage of konfd:

  -configmap value
    	the configmap to process.
  -namespace value
    	the namespace to process.
  -noop
    	print processed configmaps and secrets and do not submit them to the cluster.
  -onetime
    	run one time and exit.
  -sync-interval duration
    	the time duration between template processing. (default 1m0s)

kubectl create secret generic vault-secrets \
  --from-literal 'mysql_password=v@ulTi$d0p3'

kubectl create configmap vault-configs \
  --from-literal 'default_lease_ttl=768h' \
  --from-literal 'mysql_username=vault'

cat configmaps/vault-template.yaml

apiVersion: v1
kind: ConfigMap
metadata:
  name: vault-template
  annotations:
    konfd.io/kind: configmap
    konfd.io/name: vault
    konfd.io/key:  server.hcl
  labels:
    konfd.io/template: "true"
data:
  template: |
    default_lease_ttl = {{configmap "vault-configs" "default_lease_ttl"}}
    backend "mysql" {
      username = "{{configmap "vault-configs" "mysql_username"}}"
      password = "{{secret "vault-secrets" "mysql_password"}}"
      tls_ca_file = "/etc/tls/mysql-ca.pem"
    }

kubectl create -f configmaps/vault-template.yaml

kubectl create -f replicasets/konfd.yaml

kubectl get configmaps vault -o yaml

apiVersion: v1
kind: ConfigMap
metadata:
  name: vault
  namespace: default
data:
  server.hcl: |
    default_lease_ttl = 768h
    backend "mysql" {
      username = "vault"
      password = "v@ulTi$d0p3"
    }

kubectl proxy

konfd -onetime -noop -namespace default -configmap vault-template