Can I use env in preStop command - kubernetes

Question

Can I use environment variable in lifecycle.preStop.exec.command? I have a script that has to be run in preStop command. The answer here states that it's possible to use env variables in postStart Can I use env in postStart command. It doesn't work with preStop though. Is it a bug or am I doing something wrong?
apiVersion: apps/v1beta1
kind: Deployment
metadata:
name: loap
spec:
replicas: 1
template:
metadata:
labels:
app: loap
spec:
containers:
-
command:
- sh
- "-c"
- "echo $(date +%s): START >> /loap/timing; sleep 10; echo $(date +%s): END >> /loap/timing;"
image: busybox
env:
- name: secretThing
valueFrom:
secretKeyRef:
name: supersecret
key: password
lifecycle:
preStop:
exec:
command:
- sh
- "-c"
- "echo ${secretThing} $(date +%s): PRE-HOOK >> /loap/timing"
livenessProbe:
exec:
command:
- sh
- "-c"
- "echo $(date +%s): LIVENESS >> /loap/timing"
name: main
readinessProbe:
exec:
command:
- sh
- "-c"
- "echo $(date +%s): READINESS >> /loap/timing"
volumeMounts:
-
mountPath: /loap
name: timing
initContainers:
-
command:
- sh
- "-c"
- "echo $(date +%s): INIT >> /loap/timing"
image: busybox
name: init
volumeMounts:
-
mountPath: /loap
name: timing
volumes:
-
hostPath:
path: /tmp/loap
name: timing

Answer 1

This is explained in the Kubernetes docs Working with objects - Names.
A client-provided string that refers to an object in a resource URL, such as /api/v1/pods/some-name.
Only one object of a given kind can have a given name at a time. However, if you delete the object, you can make a new object with the same name.
By convention, the names of Kubernetes resources should be up to maximum length of 253 characters and consist of lower case alphanumeric characters, -, and ., but certain resources have more specific restrictions.