SysV vs Debian Insserv vs Upstart vs Systemd: Systemd

• Originally went into Fedora for testing and tuning.

• Not yet included in server distributions like RHEL.

• Very disruptive, big redesign of how Linux systems boot. It replaces many core parts of low level Linux.

• On the plus side, Lennart has done a very good job in explaining the rationale behind the required changes and the gains.

• Ideal design does not rely on dependencies being specified by the packagers, they are auto computed on demand. Real life is sometimes otherwise though, and requires manual dependencies.

• Like upstart, given boot order not specified, could trigger race conditions in our scripts or daemons, and only on 1% of our machines.

• Systemd sounded simple, but the implementation and getting everything right is much more complex than we're comfortable with.