diff options
author | Lennart Poettering <lennart@poettering.net> | 2010-07-03 19:54:00 +0200 |
---|---|---|
committer | Lennart Poettering <lennart@poettering.net> | 2010-07-03 19:54:00 +0200 |
commit | 62adf224d1d3e225de072a2815dd50e973230f5c (patch) | |
tree | 27e8fd16e51aa779e4190a34e41ff17fea99bb89 /man | |
parent | af65a09126e216d468592f069aee50dfe0382d3a (diff) |
man: various man page updates
Diffstat (limited to 'man')
-rw-r--r-- | man/daemon.xml | 369 | ||||
-rw-r--r-- | man/systemd.path.xml | 11 | ||||
-rw-r--r-- | man/systemd.service.xml | 69 | ||||
-rw-r--r-- | man/systemd.socket.xml | 15 | ||||
-rw-r--r-- | man/systemd.special.xml.in | 81 | ||||
-rw-r--r-- | man/systemd.target.xml | 14 | ||||
-rw-r--r-- | man/systemd.timer.xml | 11 | ||||
-rw-r--r-- | man/systemd.unit.xml | 36 |
8 files changed, 505 insertions, 101 deletions
diff --git a/man/daemon.xml b/man/daemon.xml index 1cddf38f74..853b3bb814 100644 --- a/man/daemon.xml +++ b/man/daemon.xml @@ -21,7 +21,7 @@ along with systemd; If not, see <http://www.gnu.org/licenses/>. --> -<refentry id="systemd.special"> +<refentry id="daemon"> <refentryinfo> <title>daemon</title> @@ -55,8 +55,9 @@ functionality to other processes. Traditionally, daemons are implemented following a scheme originating in SysV Unix. Modern daemons should follow a simpler - yet more powerful scheme here called "new-style" - daemons, as implemented by systemd. </para> + yet more powerful scheme (here called "new-style" + daemons), as implemented by + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>. </para> <refsect2> <title>SysV Daemons</title> @@ -64,7 +65,7 @@ <para>When a traditional SysV daemon starts, it should execute the following steps as part of the initialization. Note that these - steps are unnecessary for new-style daemons, + steps are unnecessary for new-style daemons (see below), and should only be implemented if compatibility with SysV is essential.</para> @@ -80,7 +81,7 @@ <filename>/proc/self/fd</filename>, with a fallback of iterating from file descriptor 3 to the value returned by - getrlimit() for + <function>getrlimit()</function> for RLIMIT_NOFILE.</para></listitem> <listitem><para>Reset all signal @@ -91,23 +92,30 @@ SIG_DFL.</para></listitem> <listitem><para>Reset the signal mask - using sigprocmask().</para></listitem> + using + <function>sigprocmask()</function>.</para></listitem> - <listitem><para>Call fork(), + <listitem><para>Sanitize the + environment block, removing or + resetting environment variables that + might negatively impact daemon + runtime.</para></listitem> + + <listitem><para>Call <function>fork()</function>, to create a background process.</para></listitem> <listitem><para>In the child, call - setsid() to detach from any terminal - and create an independent - session.</para></listitem> + <function>setsid()</function> to + detach from any terminal and create an + independent session.</para></listitem> <listitem><para>In the child, call - fork() again, to ensure the daemon can - never re-aquire a terminal - again.</para></listitem> + <function>fork()</function> again, to + ensure the daemon can never re-aquire + a terminal again.</para></listitem> - <listitem><para>Call exit() in the + <listitem><para>Call <function>exit()</function> in the first child, so that only the second child (the actual daemon process) stays around. This ensures that the @@ -122,7 +130,7 @@ <listitem><para>In the daemon process, reset the umask to 0, so that the file - modes passed to open(), mkdir() and + modes passed to <function>open()</function>, <function>mkdir()</function> and suchlike directly control the access mode of the created files and directories.</para></listitem> @@ -135,6 +143,23 @@ unmounted.</para></listitem> <listitem><para>In the daemon process, + write the daemon PID (as returned by + <function>getpid()</function>) to a + PID file, for example + <filename>/var/run/foobar.pid</filename> + (for a hypothetical daemon "foobar"), + to ensure that the daemon cannot be + started more than once. This must be + implemented in race-free fashion so + that the PID file is only updated when + at the same time it is verified that + the PID previously stored in the PID + file no longer exists or belongs to a + foreign process. Commonly some kind of + file locking is employed to implement + this logic.</para></listitem> + + <listitem><para>In the daemon process, drop privileges, if possible and applicable.</para></listitem> @@ -144,21 +169,25 @@ complete. This can be implemented via an unnamed pipe or similar communication channel that is created - before the first fork() and available - in both processes.</para></listitem> + before the first + <function>fork()</function> and hence + available in both the original and the + daemon process.</para></listitem> - <listitem><para>Call exit() in the + <listitem><para>Call + <function>exit()</function> in the original process. The process that invoked the daemon must be able to - rely that this exit() happens after - initialization is complete and all - external communication channels + rely that this + <function>exit()</function> happens + after initialization is complete and + all external communication channels established and accessible.</para></listitem> </orderedlist> - <para>The BSD daemon() function should not be - used, as it does only a subset of these steps.</para> + <para>The BSD <function>daemon()</function> function should not be + used, as it implements only a subset of these steps.</para> <para>A daemon that needs to provide compatibility with SysV systems should @@ -190,6 +219,17 @@ execute them when run as new-style service.</para> + <para>Note that new-style init systems + guarantee execution of daemon processes in + clean process contexts: it is guaranteed that + the environment block is sanitized, that the + signal handlers and mask is reset and that no + left-over file descriptors are passed. Daemons + will be executed in their own session, and + STDIN/STDOUT/STDERR connected to + <filename>/dev/null</filename> unless + otherwise configured. The umask is reset.</para> + <para>It is recommended for new-style daemons to implement the following:</para> @@ -207,9 +247,10 @@ this is used by the init system to detect service errors and problems. It is recommended to follow the exit code - scheme as defined in LSB - recommendations for SysV init scripts - (http://refspecs.freestandards.org/LSB_3.1.1/LSB-Core-generic/LSB-Core-generic/iniscrptact.html).</para></listitem> + scheme as defined in the <ulink + url="http://refspecs.freestandards.org/LSB_3.1.1/LSB-Core-generic/LSB-Core-generic/iniscrptact.html">LSB + recommendations for SysV init + scripts</ulink>.</para></listitem> <listitem><para>As much as possible, rely on systemd's functionality to @@ -220,7 +261,10 @@ implementing your own, rely on systemd's privilege dropping code instead of implementing it in the - daemon, and similar.</para></listitem> + daemon, and similar. See + <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for the available + controls.</para></listitem> <listitem><para>If possible and applicable expose the daemon's control @@ -239,8 +283,8 @@ boot-up speed; your daemon can be restarted on failure, without losing any bus requests, as the bus queues - requests for activatable - services.</para></listitem> + requests for activatable services. See + below for details.</para></listitem> <listitem><para>If your daemon provides services to other local @@ -255,20 +299,21 @@ protocols (such as syslog, DNS) a daemon implementing socket-based activation can be restarted without - losing a single - request.</para></listitem> + losing a single request. See below for + details.</para></listitem> <listitem><para>If applicable a daemon should notify the init system about - startup completion or status - updates via the sd_notify() + startup completion or status updates + via the + <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry> interface.</para></listitem> <listitem><para>Instead of using the - syslog() call to log directly to the + <function>syslog()</function> call to log directly to the system logger, a new-style daemon may choose to simply log to STDERR via - fprintf(), which is then forwarded to + <function>fprintf()</function>, which is then forwarded to syslog by the init system. If log priorities are necessary these can be encoded by prefixing individual log @@ -276,30 +321,259 @@ (for log priority 4 "WARNING" in the syslog priority scheme), following a similar style as the Linux kernel's - printk() priority system. In fact, using - this style of logging also enables the - init system to optionally direct all - application logging to the kernel log - buffer (kmsg), as accessible via - dmesg.</para></listitem> + <function>printk()</function> priority system. In fact, + using this style of logging also + enables the init system to optionally + direct all application logging to the + kernel log buffer (kmsg), as + accessible via + <citerefentry><refentrytitle>dmesg</refentrytitle><manvolnum>1</manvolnum></citerefentry>. This + kind of logging may be enabled by + setting + <varname>StandardError=syslog</varname> + in the service unit file. For details + see + <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry> + and + <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> </orderedlist> + + <para>These recommendations are similar but + not identical to the <ulink + url="http://developer.apple.com/mac/library/documentation/MacOSX/Conceptual/BPSystemStartup/Articles/LaunchOnDemandDaemons.html#//apple_ref/doc/uid/TP40001762-104738">Apple + MacOS X Daemon Requirements</ulink>.</para> </refsect2> <refsect2> - <title>Bus Activation</title> + <title>Socket-Based Activation</title> </refsect2> <refsect2> - <title>Socket Activation</title> + <title>Bus-Based Activation</title> </refsect2> <refsect2> - <title>Writing Service Files</title> + <title>Path-Based Activation</title> + </refsect2> + + <refsect2> + <title>Writing Systemd Unit Files</title> + + <para>When writing systemd unit files, it is + recommended to consider the following + suggestions:</para> + + <orderedlist> + <listitem><para>If possible do not use + the <varname>Type=forking</varname> + setting in service files. But if you + do, make sure to set the PID file path + using <varname>PIDFile=</varname>. See + <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for details.</para></listitem> + + <listitem><para>If your daemon + registers a D-Bus name on the bus, + make sure to use + <varname>Type=dbus</varname> if + possible.</para></listitem> + + <listitem><para>Make sure to set a + good human-readable description string + with + <varname>Description=</varname>.</para></listitem> + + <listitem><para>Do not disable + <varname>DefaultDependencies=</varname>, + unless you really know what you do and + your unit is involved in early boot or + late system shutdown.</para></listitem> + + <listitem><para>Normally, little if + any dependencies should need to + be defined explicitly. However, if you + do configure explicit dependencies, only refer to + unit names listed on + <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry> + or names introduced by your own + package to keep the unit file + operating + system-independent.</para></listitem> + + <listitem><para>Make sure to include + an <literal>[Install]</literal> section including + installation information for the unit + file. See + <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for details. To activate your service + on boot make sure to add a + <varname>WantedBy=multi-user.target</varname> + or + <varname>WantedBy=graphical.target</varname> directive.</para></listitem> + + </orderedlist> </refsect2> <refsect2> <title>Installing Service Files</title> + + <para>At the build installation time + (e.g. <command>make install</command> during + package build) packages are recommended to + install their systemd unit files in the + directory returned by <command>pkg-config + systemd + --variable=systemdsystemnunitdir</command> + (for system services), + resp. <command>pkg-config systemd + --variable=systemdsessionunitdir</command> + (for session services). This will make the + services available in the system on explicit + request but not activate them automatically + during boot. Optionally, during package + installation (e.g. <command>rpm -i</command> + by the administrator) symlinks should be + created in the systemd configuration + directories via the + <citerefentry><refentrytitle>systemd-install</refentrytitle><manvolnum>1</manvolnum></citerefentry> + tool, to activate them automatically on + boot.</para> + + <para>Packages using + <citerefentry><refentrytitle>autoconf</refentrytitle><manvolnum>1</manvolnum></citerefentry> + are recommended to use a configure script + excerpt like the following to determine the + unit installation path during source + configuration:</para> + + <programlisting>PKG_PROG_PKG_CONFIG +AC_ARG_WITH([systemdsystemunitdir], + AS_HELP_STRING([--with-systemdsystemunitdir=DIR], [Directory for systemd service files]), + [], [with_systemdsystemunitdir=$($PKG_CONFIG --variable=systemdsystemunitdir systemd)]) +AC_SUBST([systemdsystemunitdir], [$with_systemdsystemunitdir]) +AM_CONDITIONAL(HAVE_SYSTEMD, [test -n "$with_systemdsystemunitdir"])</programlisting> + + <para>This snippet allows automatic + installation of the unit files on systemd + machines, and optionally allows their + installation even on machines lacking + systemd. (Modification of this snippet for the + session unit directory is left as excercise to the + reader.)</para> + + <para>Additionally, to ensure that + <command>make distcheck</command> continues to + work, it is recommended to add the following + to the top-level <filename>Makefile.am</filename> + file in + <citerefentry><refentrytitle>automake</refentrytitle><manvolnum>1</manvolnum></citerefentry>-based + projects:</para> + + <programlisting>DISTCHECK_CONFIGURE_FLAGS = \ + --with-systemdsystemunitdir=$$dc_install_base/$(systemdsystemunitdir)</programlisting> + + <para>Finally, unit files should be installed in the system with an automake excerpt like the following:</para> + + <programlisting>if HAVE_SYSTEMD +systemdsystemunit_DATA = \ + foobar.socket \ + foobar.service +endif</programlisting> + + <para>In the + <citerefentry><refentrytitle>rpm</refentrytitle><manvolnum>8</manvolnum></citerefentry> + <filename>.spec</filename> file use a snippet like + the following to enable/disable the service + during installation/deinstallation. Consult + the packaging guidelines of your distribution + for details and the equivalent for other + packaging managers:</para> + + <programlisting>%post +/usr/bin/systemd-install enable foobar.service foobar.socket >/dev/null 2>&1 || : + +%preun +if [ "$1" -eq 0 ]; then + /usr/bin/systemd-install disable foobar.service foobar.socket >/dev/null 2>&1 || : +fi</programlisting> + + </refsect2> + + <refsect2> + <title>Porting Existing Daemons</title> + + <para>Since new-style init systems such as + systemd are compatible with traditional SysV + init systems it is not strictly necessary to + port existing daemons to the new + style. However doing this offers additional + functionality to the daemons as well as it + simplifies integration into new-style init + systems.</para> + + <para>To port an existing SysV compatible + daemon the following steps are + recommended:</para> + + <orderedlist> + <listitem><para>If not already + implemented, add an optional command + line switch to the daemon to disable + daemonization. This is useful not only + for using the daemon in new-style init + systems, but also to ease debugging.</para></listitem> + + <listitem><para>If the daemon offers + interfaces to other software running + on the local system via local AF_UNIX + sockets, consider implementing + socket-based activation (see + above). Usually a minimal patch is + sufficient to implement this: Extend + the socket creation in the daemon code + so that + <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry> + is checked for already passed sockets + first. If sockets are passed + (i.e. when + <function>sd_listen_fds()</function> + returns a positive value), skip the + socket createn step and use the passed + sockets. Secondly, ensure that the + file-system socket nodes for local + AF_UNIX sockets used in the + socket-based activation are not + removed when the daemon shuts down, if + sockets have been passed. Third, if + the daemon normally closes all + remaining open file descriptors as + part of its initialization, the + sockets passed from the init system + must be spared. Since new-style init + systems guarantee that no left-over + file descriptors are passed to + executed processes, it might be a good + choice to simply skip the closing of + all remaining open file descriptors if + file descriptors are + passed.</para></listitem> + + <listitem><para>Write and install a + systemd unit file for the service (and + the sockets if socket-based activation + is used, as well as a path unit file, + if the daemon processes a spool + directory), see above for + details.</para></listitem> + + <listitem><para>If the daemon exposes + interfaces via D-Bus, write and + install a D-Bus activation file for + the service, see above for + details.</para></listitem> + </orderedlist> + </refsect2> </refsect1> @@ -309,8 +583,11 @@ <title>See Also</title> <para> <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, - <citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry> + <citerefentry><refentrytitle>systemd-install</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry> </para> </refsect1> diff --git a/man/systemd.path.xml b/man/systemd.path.xml index 772190096d..d910d2c5c8 100644 --- a/man/systemd.path.xml +++ b/man/systemd.path.xml @@ -87,6 +87,17 @@ <para>If an path unit is beneath another mount point in the file system hierarchy, a dependency between both units is created automatically.</para> + + <para>Unless <varname>DefaultDependencies=</varname> + is set to <option>false</option>, path units will + implicitly have dependencies of type + <varname>Conflicts=</varname> and + <varname>Before=</varname> on + <filename>shutdown.target</filename>. These ensure + that path units are terminated cleanly prior to system + shutdown. Only path units involved with early boot or + late system shutdown should disable this + option.</para> </refsect1> <refsect1> diff --git a/man/systemd.service.xml b/man/systemd.service.xml index b01641f1e4..91d6d09409 100644 --- a/man/systemd.service.xml +++ b/man/systemd.service.xml @@ -64,27 +64,44 @@ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for the common options of all unit configuration files. The common configuration items are configured - in the generic [Unit] and [Install] sections. The - service specific configuration options are configured - in the [Service] section.</para> + in the generic <literal>[Unit]</literal> and + <literal>[Install]</literal> sections. The service + specific configuration options are configured in the + <literal>[Service]</literal> section.</para> <para>Additional options are listed in <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>, which define the execution environment the commands are executed in.</para> + + <para>Unless <varname>DefaultDependencies=</varname> + is set to <option>false</option>, service units will + implicitly have dependencies of type + <varname>Requires=</varname> and + <varname>After=</varname> on + <filename>basic.target</filename> as well as + dependencies of type <varname>Conflicts=</varname> and + <varname>Before=</varname> on + <filename>shutdown.target</filename>. These ensure + that normal service units pull in basic system + initialization, and are terminated cleanly prior to + system shutdown. Only services involved with early + boot or late system shutdown should disable this + option.</para> </refsect1> <refsect1> <title>Options</title> - <para>Service files must include a [Service] section, - which carries information about the service and the - process it supervises. A number of options that may be - used in this section are shared with other unit - types. These options are documented in + <para>Service files must include a + <literal>[Service]</literal> section, which carries + information about the service and the process it + supervises. A number of options that may be used in + this section are shared with other unit types. These + options are documented in <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The - options specific to the [Service] section of service - units are the following:</para> + options specific to the <literal>[Service]</literal> + section of service units are the following:</para> <variablelist> <varlistentry> @@ -143,14 +160,18 @@ <para>Behaviour of <option>dbus</option> is similar to - <option>simple</option>, however it - is expected that the daemon acquires a + <option>simple</option>, however it is + expected that the daemon acquires a name on the D-Bus bus, as configured by <varname>BusName=</varname>. systemd will proceed starting follow-up units after the D-Bus bus name has been - acquired.</para> + acquired. Service units with this + option configured implicitly have + dependencies on the + <filename>dbus.target</filename> + unit.</para> <para>Behaviour of <option>notify</option> is similar to @@ -163,10 +184,13 @@ starting follow-up units after this notification message has been sent. If this option is used - <option>NotifyAccess=</option> (see + <varname>NotifyAccess=</varname> (see below) must be set to open access to the notification socket provided by - systemd.</para> + systemd. If + <varname>NotifyAccess=</varname> is not + set, it will be implicitly set to + <option>main</option>.</para> </listitem> </varlistentry> @@ -220,11 +244,12 @@ services. This option may not be specified more than once. Optionally, if the absolute file name is prefixed - with @, the second token will be - passed as argv[0] to the executed - process, followed by the further - arguments specified. Unless - <option>Type=forking</option> is set, + with <literal>@</literal>, the second + token will be passed as + <literal>argv[0]</literal> to the + executed process, followed by the + further arguments specified. Unless + <varname>Type=forking</varname> is set, the process started via this command line will be considered the main process of the @@ -312,7 +337,7 @@ forcibly via SIGTERM, and after another delay of this time with SIGKILL. (See - <option>KillMode=</option> + <varname>KillMode=</varname> below.) Takes a unit-less value in seconds, or a time span value such as "5min 20s". Pass 0 to disable the timeout @@ -450,7 +475,7 @@ <para>Processes will first be terminated via SIGTERM. If then after a delay (configured via the - <option>TimeoutSec=</option> option) + <varname>TimeoutSec=</varname> option) processes still remain, the termination request is repeated with the SIGKILL signal. See diff --git a/man/systemd.socket.xml b/man/systemd.socket.xml index 986ef8c018..6154b304e8 100644 --- a/man/systemd.socket.xml +++ b/man/systemd.socket.xml @@ -95,6 +95,21 @@ which services are instantiated for each incoming connection.</para> + <para>Unless <varname>DefaultDependencies=</varname> + is set to <option>false</option>, socket units will + implicitly have dependencies of type + <varname>Requires=</varname> and + <varname>After=</varname> on + <filename>sysinit.target</filename> as well as + dependencies of type <varname>Conflicts=</varname> and + <varname>Before=</varname> on + <filename>shutdown.target</filename>. These ensure + that socket units pull in basic system + initialization, and are terminated cleanly prior to + system shutdown. Only sockets involved with early + boot or late system shutdown should disable this + option.</para> + <para>Socket units may be used to implement on-demand starting of services, as well as parallelized starting of services.</para> diff --git a/man/systemd.special.xml.in b/man/systemd.special.xml.in index 79c6db1a5b..49dc3892c0 100644 --- a/man/systemd.special.xml.in +++ b/man/systemd.special.xml.in @@ -51,6 +51,7 @@ <para><filename>basic.target</filename>, <filename>ctrl-alt-del.target</filename>, <filename>@SPECIAL_DBUS_SERVICE@</filename>, + <filename>dbus.target</filename>, <filename>default.target</filename>, <filename>display-manager.service</filename>, <filename>emergency.service</filename>, @@ -78,8 +79,8 @@ <filename>sockets.target</filename>, <filename>swap.target</filename>, <filename>sysinit.target</filename>, - <filename>syslog.target</filename>, <filename>@SPECIAL_SYSLOG_SERVICE@</filename>, + <filename>syslog.target</filename>, <filename>systemd-initctl.service</filename>, <filename>systemd-initctl.socket</filename>, <filename>systemd-logger.service</filename>, @@ -141,6 +142,28 @@ up systemd will connect to it and register its service.</para> + + <para>Units should generally + avoid depending on this unit + directly and instead refer to + the + <filename>dbus.target</filename> + unit instead, which pulls this + one in directly or indirectly + via socket-based activation.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><filename>dbus.target</filename></term> + <listitem> + <para>Administrators should + ensure that this target pulls + in a service unit with the + name or alias of + <filename>@SPECIAL_DBUS_SERVICE@</filename> + (or a socket unit that + activates this + service).</para> </listitem> </varlistentry> <varlistentry> @@ -523,28 +546,6 @@ </listitem> </varlistentry> <varlistentry> - <term><filename>syslog.target</filename></term> - <listitem> - <para>systemd automatically - adds dependencies of type - After for this target unit to - all SysV init script service - units with an LSB header - referring to the - <literal>$syslog</literal> - facility.</para> - - <para>Administrators should - ensure that this target pulls - in a service unit with the - name or alias of - <filename>@SPECIAL_SYSLOG_SERVICE@</filename> - (or a socket unit that - activates this - service).</para> - </listitem> - </varlistentry> - <varlistentry> <term><filename>sysinit.target</filename></term> <listitem> <para>A special target unit @@ -571,11 +572,37 @@ and use it for logging if it has been configured for that.</para> - <para>Applications should - generally not depend on this - service, and depend on + + <para>Units should generally + avoid depending on this unit + directly and instead refer to + the <filename>syslog.target</filename> - instead.</para> + unit instead, which pulls this + one in directly or indirectly + via socket-based activation.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><filename>syslog.target</filename></term> + <listitem> + <para>systemd automatically + adds dependencies of type + After for this target unit to + all SysV init script service + units with an LSB header + referring to the + <literal>$syslog</literal> + facility.</para> + + <para>Administrators should + ensure that this target pulls + in a service unit with the + name or alias of + <filename>@SPECIAL_SYSLOG_SERVICE@</filename> + (or a socket unit that + activates this + service).</para> </listitem> </varlistentry> <varlistentry> diff --git a/man/systemd.target.xml b/man/systemd.target.xml index 88a9e6eada..6f3bc182dc 100644 --- a/man/systemd.target.xml +++ b/man/systemd.target.xml @@ -76,12 +76,22 @@ dependencies between units. Among other things, target units are a more flexible replacement for SysV runlevels in the classic SysV init system. (And for - compatibility reasons there exist special + compatibility reasons special target units such as - <filename>runlevel3.target</filename> which are used by + <filename>runlevel3.target</filename> exist which are used by the SysV runlevel compatibility code in systemd. See <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry> for details).</para> + + <para>Unless + <varname>DefaultDependencies=</varname> is set to + <option>false</option>, target units will + implicitly complement all configured dependencies of type + <varname>Wants=</varname>, + <varname>Requires=</varname>, + <varname>RequiresOverridable=</varname> with + dependencies of type <varname>After=</varname>. + </para> </refsect1> <refsect1> diff --git a/man/systemd.timer.xml b/man/systemd.timer.xml index 7a4cd34887..ef89693f14 100644 --- a/man/systemd.timer.xml +++ b/man/systemd.timer.xml @@ -76,6 +76,17 @@ matching service <filename>foo.service</filename>. The unit to activate may be controlled by <varname>Unit=</varname> (see below).</para> + + <para>Unless <varname>DefaultDependencies=</varname> + is set to <option>false</option>, timer units will + implicitly have dependencies of type + <varname>Conflicts=</varname> and + <varname>Before=</varname> on + <filename>shutdown.target</filename>. These ensure + that timer units are stopped cleanly prior to system + shutdown. Only timer units involved with early boot or + late system shutdown should disable this + option.</para> </refsect1> <refsect1> diff --git a/man/systemd.unit.xml b/man/systemd.unit.xml index 9c4269f3d2..26272c4410 100644 --- a/man/systemd.unit.xml +++ b/man/systemd.unit.xml @@ -215,10 +215,10 @@ <varlistentry> <term><varname>Description=</varname></term> <listitem><para>A free-form string - describing the unit. This is intended for use - in UIs wanting to show - descriptive information along with the - unit name.</para></listitem> + describing the unit. This is intended + for use in UIs to show descriptive + information along with the unit + name.</para></listitem> </varlistentry> <varlistentry> @@ -451,6 +451,34 @@ <option>false</option>.</para></listitem> </varlistentry> + <varlistentry> + <term><varname>DefaultDependencies=</varname></term> + + <listitem><para>Takes a boolean + argument. If <option>true</option> + (the default), a few default + dependencies will implicitly be + created for the unit. The actual + dependencies created depend on the + unit type. For example, for service + units, these dependencies ensure that + the service is started only after + basic system initialization is + complete and is properly terminated on + system shutdown. See the respective + man pages for details. Generally, only + services involved with early boot or + late shutdown should set this option + to <option>false</option>. It is + highly recommended to leave this + option enabled for the majority of + common units. If set to + <option>false</option> this option + does not disable all implicit + dependencies, just non-essential + ones.</para></listitem> + </varlistentry> + </variablelist> <para>Unit file may include a [Install] section, which |