Unable to change graphroot with STORAGE_OPTS?

[GrabbenD]

I'm trying to temporarily change root storage for Podman from /var/lib/containers/storage to /tmp/podman/storage but my attempts have been unsuccessful:

$ export STORE=/tmp/podman

$ export STORAGE_OPTS=storage.graphroot=${STORE}/storage
Error: overlay: Unknown option storage.graphroot

$ export STORAGE_OPTS=graphroot=${STORE}/storage
Error: overlay: Unknown option graphroot

$ export STORAGE_OPTS=root=${STORE}/storage
Error: overlay: Unknown option root

$ export STORAGE_OPTS=${STORE}/storage
Error: unable to parse key/value option: /tmp/podman/storage

I've used this as a reference:

• https://docs.podman.io/en/latest/markdown/podman.1.html#root-value
• https://github.com/containers/storage/blob/main/docs/containers-storage.conf.5.md

What am I doing wrong?

[GrabbenD]

Looks like STORAGE_OPTS is just for customizing contents of storage.options (https://github.com/containers/storage/blob/main/docs/containers-storage.conf.5.md#storage-table) for instance:

$ export STORAGE_OPTS=overlay.ignore_chown_errors=true

What would be the closest alternative to customizing graphroot as a environment variable (without using --root) in that case?