### Secrets Sync cannot be activated from chroot namespace

#### Affected versions

- 1.16.0+

#### Issue

Secrets Sync cannot be activated from the chroot namespace. The Secrets Sync feature
now requires a new activation-flag to be enabled before it can be used. Writing to
any `sys/activation-flags/` path currently requires root namespace access.

#### Workaround
Users can request a Vault operator to activate the feature from the root namespace
if they lack the necessary access.
