Fedora 18 was released with systemd-195. In subsequent F18 updates systemd has
been rebased to a newer upstream version. Several of the upstream changes could
introduce incompatible behavior within a Fedora release. Care has been taken
to avoid adding such changes in the stable Fedora updates. This leads to the
following areas where systemd in Fedora 18 differs from the upstream version:

- rescue.service can start sushell if configured so by /etc/sysconfig/init.
  Upstream supports only sulogin.

- http-daemon.target, mail-transfer-agent.target, the LSB facilities "httpd",
  "MTA", "smtpdaemon", "mail-transfer-agent", "mail-transport-agent", "smtp",
  "x-display-manager" were removed upstream, but they are preserved in
  Fedora 18.

- The alias "single.service" for "rescue.service" is provided.

- A hacky workaround that allows udev to rename network interfaces into
  kernel's ethX namespace has been re-added. This is to support users who still
  rely on udev rules such as 70-persistent-net.rules generated in previous
  Fedora releases to name their network interfaces. Note that the workaround is
  only temporary and will go away in a future Fedora release. Also note that
  due to unavoidable race conditions, the workaround can still fail
  occasionally (causing network interfaces to be named renameX).
  To be on the safe side it is recommended to change any present network
  interface naming udev rules to use network interface names that cannot
  collide with kernel generated names as soon as possible.

- Though "systemctl dot" does not work anymore, at least it prints an advice
  to use "systemd-analyze dot" instead.

- The udev support for predictable network interface names is present, but it
  is not enabled by default. Users interested in the feature have to opt-in by
  passing the parameter "net.ifnames=1" on the kernel command line.

- A persistent journal is not created by default. Users may opt-in by creating
  /var/log/journal with appropriate ACLs manually:
    mkdir /var/log/journal
    setfacl -Rnm g:wheel:rx,d:g:wheel:rx,g:adm:rx,d:g:adm:rx /var/log/journal/

- A dummy syslog.target unit is provided in F18 as a workaround for broken unit
  files that have requirement dependencies (such as Requires) on it. The units
  must be fixed for future Fedora releases.

- The precedence rules for sysctl.d files are inverted. Files with lexically
  later names override files with earlier names.

- The Fedora package contains bugfixes and minor features cherry-picked from
  later upstream versions than the RPM package version indicates.