Documentation Boot Beat
stateless systems (note)
A lot of work is being done here on stateless systems - aka bootup with minimal configuration. look into that, talk to systemd maintainers to see if this functionality exists in a marketable state.
systemd-sysusers creates system users on demand
A new tool, `systemd-sysusers`, can be used to create system users and groups on startup. On startup, the `systemd-sysusers` service reads configuration files in /usr/lib/sysusers.d/, which are provided by packages or adminstrators, and creates the relevant entries in /etc/passwd and /etc/groups.
These configuration files can be used to create users, create groups, or add users to a group. The syntax for entries in these files is defined in `man 5 sysusers.d`.
By default, `systemd` provides configurations for required users like root, required groups such as wheel, and common system groups such as dialout, video, or users.
The existence of `systemd-sysusers` ensures that a system can boot and be accessible, even if the /etc directory is not present - whether by design in a stateless system, or due to a system fault. Fedora 21 will still provide a default /etc/passwd and /etc/groups, and does not rely on `systemd-sysusers` exclusively to provide these system accounts.
ConditionNeedsUpdate= for unit definitions
`systemd` follows the convention of providing distribution provided configurations in /usr/, and overriding those with configurations from administrators in /etc/. If the files in /etc ( or /var) are 'older' than their counterparts in /usr/, the conditional directive "ConditionNeedsUpdate" is executed.