@title Managing Daemons with phd
@group config

Explains Phabricator daemons and the daemon control program ##phd##.

= Overview =

Phabricator uses daemons (background processing scripts) to handle a number of
tasks, like:

  - tracking repositories and discovering new commits;
  - sending mail;
  - updating objects in the search index; and
  - custom tasks you define.

Daemons are started and stopped with **phd** (the **Ph**abricator **D**aemon
launcher). Daemons can be monitored via a web console.

You do not need to run daemons for most parts of Phabricator to work, but a few
features (principally, repository tracking with Diffusion) require them and
several features will benefit in performance or stability if you configure
daemons.

= phd =

**phd** is a command-line script (located at ##phabricator/bin/phd##). To get
a list of commands, run ##phd help##:

  phabricator/ $ ./bin/phd help
  NAME
          phd - phabricator daemon launcher
  ...

Generally, you will use:

  - **phd launch** to launch daemons;
  - **phd debug** to debug problems with daemons;
  - **phd status** to get a list of running daemons; and
  - **phd stop** to stop all daemons.

NOTE: When you upgrade Phabricator or change configuration, you should restart
the daemons by stopping and relaunching them.

NOTE: When you **launch** a daemon, you can type any unique substring of its
name, so **phd launch metamta** will work correctly.

= Daemon Console =

You can view status and debugging information for daemons in the Daemon Console
via the web interface. Go to ##/daemon/## in your install or click
**Daemon Console** from the homepage.

The Daemon Console shows a list of all the daemons that have ever launched, and
allows you to view log information for them. If you have issues with daemons,
you may be able to find error information that will help you resolve the problem
in the console.

NOTE: The easiest way to figure out what's wrong with a daemon is usually to use
**phd debug** to launch it instead of **phd launch**. This will run it without
daemonizing it, so you can see output in your console.

= Available Daemons =

You can get a list of launchable daemons with **phd list**:

  - **libphutil test daemons** are not generally useful unless you are
    developing daemon infrastructure or debugging a daemon problem;
  - **PhabricatorMetaMTADaemon** sends mail in the background, see
    @{article:Configuring Outbound Email} for details;
  - **PhabricatorTaskmasterDaemon** runs a generic task queue; and
  - **PhabricatorRepository** daemons track repositories, descriptions are
    available in the @{article:Diffusion User Guide}.
  - **PhabricatorGarbageCollectorDaemon** cleans up old logs and caches.