Upstart

Upstart
Original author(s) Scott James Remnant
Developer(s) Canonical Ltd.
Initial release August 24, 2006 (2006-08-24)
Stable release
1.13[1] / July 11, 2014 (2014-07-11)
Written in C
Operating system Linux
Type Init daemon
License GPLv2
Website upstart.ubuntu.com

Upstart is an event-based replacement for the traditional init daemon – the method by which several Unix-like computer operating systems perform tasks when the computer is started. It was written by Scott James Remnant, a former employee of Canonical Ltd.

Rationale

The traditional init process was originally only responsible for bringing the computer into a normal running state after power-on, or gracefully shutting down services prior to shutdown. As a result, the design is strictly synchronous, blocking future tasks until the current one has completed. Its tasks must also be defined in advance, as they are limited to this prep or cleanup function. This leaves it unable to handle various non-startup-tasks on a modern desktop computer elegantly, including:

Upstart's event-driven model allows it to respond to events asynchronously as they are generated.[2]

Design

Upstart operates asynchronously; it handles starting of the tasks and services during boot and stopping them during shutdown, and also supervises the tasks and services while the system is running.

Easy transition and perfect backward compatibility with sysvinit were the explicit design goals;[3] accordingly, Upstart can run unmodified sysvinit scripts. In this way it differs from most other init replacements (beside systemd and OpenRC), which usually assume and require complete transition to run properly, and do not support a mixed environment of traditional and new startup methods.[4]

Upstart allows for extensions to its event model through the use of initctl to input custom, single events, or event bridges to integrate many or more-complicated events.[5] By default, Upstart includes bridges for socket, dbus, udev, file, and dconf events; additionally, more bridges are possible.[6]

Adoption

Linux distributions and other operating systems based on the Linux kernel which use Upstart as the default init system:

Linux distributions that support or have supported Upstart to some extent, but moved away since or no longer use it as their default init system:

See also

References

  1. ↑ "Upstart 1.13 released". Ubuntu.com. Retrieved 2014-07-12.
  2. ↑ Remnant, Scott James (2006-08-26). "Upstart in Universe". Netsplit. Retrieved 2009-09-12.
  3. ↑ "Upstart", Launch Pad (605007), Ubuntu
  4. ↑ "Discussion of design and implementation of Upstart", Ubuntu Wiki, Canonical
  5. ↑ "The Upstart Cookbook: initctl emit". Canonical. Retrieved 26 January 2014.
  6. ↑ "The Upstart Cookbook: Bridges". Canonical. Retrieved 26 January 2014.
  7. ↑ "Upstart", About, Ubuntu
  8. ↑ Shuttleworth, Mark. "Losing graciously". Archived from the original on 22 March 2014. Retrieved 14 February 2014.
  9. ↑ Software Architecture: Chromium OS design documents, Google, retrieved 25 January 2014
  10. ↑ The Debian technical committee vote concludes, Lwn.net, 2014-02-11, retrieved 2014-02-11
  11. ↑ Petter Reinholdtsen (2009-09-05), The future of the boot system in Debian, Debian.org
  12. ↑ RM: upstart -- RoQA; unmaintained, debian.org, 2015-12-18, retrieved 2016-01-26
  13. ↑ VividVervet/ReleaseNotes, 2015-04-24
  14. ↑ Fedora 14 Accepted Features, 2010-07-13, retrieved 2010-07-13
  15. ↑ "Fedora defers systemd to F15". Linux Weekly News. 2010-09-14. Retrieved 2010-09-17.
  16. ↑ "Deployment". Red Hat Enterprise Linux 6: Technical Notes. Red Hat. Retrieved 2013-12-31.
  17. ↑ Poettering, Lennart (2013-06-19), Red Hat Summit talk about systemd in RHEL 7 is now available online, Google Plus, retrieved 2013-12-31
  18. ↑ Tim Burke (2012-06-27), "Red Hat Enterprise Linux Roadmap Highlights" (PDF), presentation
  19. ↑ OpenSUSE gets an Upstart, The H, 2010-03-26, archived from the original on 8 December 2013, retrieved 2010-04-04
  20. ↑ Chris von Eitzen (2011-11-16), openSUSE 12.1 arrives with systemd and Btrfs, The H, archived from the original on 20 April 2012, retrieved 2011-11-16
  21. ↑ Garrett, Matthew (2009-06-10), Palm Pre, archived from the original on 2009-12-23, retrieved 2009-07-09
  22. ↑ Fremantle, Maemo, retrieved 2009-08-24
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