reboot mechanism is accessible via the new "systemctl soft-reboot"
command.
+ * Services using RootDirectory= or RootImage= will now have read-only
+ access to a copy of the host's os-release file under
+ /run/host/os-release, which will be kept up-to-date on 'soft-reboot'.
+ This was already the case for Portable Services, and the feature has
+ now been extended to all services that do not run off the host's
+ root filesystem.
+
* A new service setting MemoryKSM= has been added to enable kernel
same-page merging individually for services.