man/systemd.mount.xml

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   9   Copyright 2010 Lennart Poettering
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  24
  25 <refentry id="systemd.mount">
  26         <refentryinfo>
  27                 <title>systemd.mount</title>
  28                 <productname>systemd</productname>
  29
  30                 <authorgroup>
  31                         <author>
  32                                 <contrib>Developer</contrib>
  33                                 <firstname>Lennart</firstname>
  34                                 <surname>Poettering</surname>
  35                                 <email>lennart@poettering.net</email>
  36                         </author>
  37                 </authorgroup>
  38         </refentryinfo>
  39
  40         <refmeta>
  41                 <refentrytitle>systemd.mount</refentrytitle>
  42                 <manvolnum>5</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>systemd.mount</refname>
  47                 <refpurpose>Mount unit configuration</refpurpose>
  48         </refnamediv>
  49
  50         <refsynopsisdiv>
  51                 <para><filename><replaceable>mount</replaceable>.mount</filename></para>
  52         </refsynopsisdiv>
  53
  54         <refsect1>
  55                 <title>Description</title>
  56
  57                 <para>A unit configuration file whose name ends in
  58                 <literal>.mount</literal> encodes information about
  59                 a file system mount point controlled and supervised by
  60                 systemd.</para>
  61
  62                 <para>This man page lists the configuration options
  63                 specific to this unit type. See
  64                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  65                 for the common options of all unit configuration
  66                 files. The common configuration items are configured
  67                 in the generic [Unit] and [Install] sections. The
  68                 mount specific configuration options are configured
  69                 in the [Mount] section.</para>
  70
  71                 <para>Additional options are listed in
  72                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  73                 which define the execution environment the
  74                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  75                 binary is executed in, and in
  76                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  77                 which define the way the processes are terminated, and
  78                 in
  79                 <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  80                 which configure resource control settings for the
  81                 processes of the service. Note that the User= and
  82                 Group= options are not particularly useful for mount
  83                 units specifying a <literal>Type=</literal> option or
  84                 using configuration not specified in
  85                 <filename>/etc/fstab</filename>;
  86                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  87                 will refuse options that are not listed in
  88                 <filename>/etc/fstab</filename> if it is not run as
  89                 UID 0.</para>
  90
  91                 <para>Mount units must be named after the mount point
  92                 directories they control. Example: the mount point
  93                 <filename noindex='true'>/home/lennart</filename> must be configured
  94                 in a unit file
  95                 <filename>home-lennart.mount</filename>. For details
  96                 about the escaping logic used to convert a file system
  97                 path to a unit name see
  98                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
  99
 100                 <para>Optionally, a mount unit may be accompanied by
 101                 an automount unit, to allow on-demand or parallelized
 102                 mounting. See
 103                 <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 104
 105                 <para>If a mount point is beneath another mount point
 106                 in the file system hierarchy, a dependency between both
 107                 units is created automatically.</para>
 108
 109                 <para>Mount points created at runtime (independently of
 110                 unit files or <filename>/etc/fstab</filename>) will be
 111                 monitored by systemd and appear like any other mount
 112                 unit in systemd.
 113                 See <filename>/proc/self/mountinfo</filename> description
 114                 in <citerefentry><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 115                 </para>
 116
 117                 <para>Some file systems have special semantics as API
 118                 file systems for kernel-to-userspace and
 119                 userspace-to-userpace interfaces. Some of them may not
 120                 be changed via mount units, and cannot be disabled.
 121                 For a longer discussion see <ulink
 122                 url="http://www.freedesktop.org/wiki/Software/systemd/APIFileSystems">API
 123                 File Systems</ulink>.</para>
 124         </refsect1>
 125
 126         <refsect1>
 127                 <title><filename>/etc/fstab</filename></title>
 128
 129                 <para>Mount units may either be configured via unit
 130                 files, or via <filename>/etc/fstab</filename> (see
 131                 <citerefentry><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 132                 for details). Mounts listed in
 133                 <filename>/etc/fstab</filename> will be converted into
 134                 native units dynamically at boot and when the
 135                 configuration of the system manager is reloaded. See
 136                 <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 137                 for details about the conversion.</para>
 138
 139                 <para>When reading <filename>/etc/fstab</filename> a
 140                 few special mount options are understood by systemd
 141                 which influence how dependencies are created for mount
 142                 points from <filename>/etc/fstab</filename>. systemd
 143                 will create a dependency of type
 144                 <option>Wants</option> from either
 145                 <filename>local-fs.target</filename> or
 146                 <filename>remote-fs.target</filename>, depending
 147                 whether the file system is local or remote. If
 148                 <option>x-systemd.automount</option> is set, an
 149                 automount unit will be created for the file
 150                 system. See
 151                 <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 152                 for details. If
 153                 <option>x-systemd.device-timeout=</option> is
 154                 specified, it may be used to configure how long systemd
 155                 should wait for a device to show up before giving up
 156                 on an entry from
 157                 <filename>/etc/fstab</filename>. Specify a time in
 158                 seconds or explicitly specify a unit as
 159                 <literal>s</literal>, <literal>min</literal>,
 160                 <literal>h</literal>, <literal>ms</literal>.</para>
 161
 162                 <para>If a mount point is configured in both
 163                 <filename>/etc/fstab</filename> and a unit file that
 164                 is stored below <filename>/usr</filename>, the former
 165                 will take precedence. If the unit file is stored below
 166                 <filename>/etc</filename>, it will take
 167                 precedence. This means: native unit files take
 168                 precedence over traditional configuration files, but
 169                 this is superseded by the rule that configuration in
 170                 <filename>/etc</filename> will always take precedence
 171                 over configuration in
 172                 <filename>/usr</filename>.</para>
 173         </refsect1>
 174
 175         <refsect1>
 176                 <title>Options</title>
 177
 178                 <para>Mount files must include a [Mount] section,
 179                 which carries information about the file system mount points it
 180                 supervises. A number of options that may be used in
 181                 this section are shared with other unit types. These
 182                 options are documented in
 183                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 184                 and
 185                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
 186                 options specific to the [Mount] section of mount
 187                 units are the following:</para>
 188
 189                 <variablelist class='unit-directives'>
 190
 191                         <varlistentry>
 192                                 <term><varname>What=</varname></term>
 193                                 <listitem><para>Takes an absolute path
 194                                 of a device node, file or other
 195                                 resource to mount. See
 196                                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 197                                 for details. If this refers to a
 198                                 device node, a dependency on the
 199                                 respective device unit is
 200                                 automatically created. (See
 201                                 <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information.)
 202                                 This option is
 203                                 mandatory.</para></listitem>
 204                         </varlistentry>
 205
 206                         <varlistentry>
 207                                 <term><varname>Where=</varname></term>
 208                                 <listitem><para>Takes an absolute path
 209                                 of a directory of the mount point. If
 210                                 the mount point does not exist at the
 211                                 time of mounting, it is created. This
 212                                 string must be reflected in the unit
 213                                 filename. (See above.) This option is
 214                                 mandatory.</para></listitem>
 215                         </varlistentry>
 216
 217                         <varlistentry>
 218                                 <term><varname>Type=</varname></term>
 219                                 <listitem><para>Takes a string for the
 220                                 file system type. See
 221                                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 222                                 for details. This setting is
 223                                 optional.</para></listitem>
 224                         </varlistentry>
 225
 226                         <varlistentry>
 227                                 <term><varname>Options=</varname></term>
 228
 229                                 <listitem><para>Mount options to use
 230                                 when mounting. This takes a
 231                                 comma-separated list of options. This
 232                                 setting is optional.</para></listitem>
 233                         </varlistentry>
 234
 235                         <varlistentry>
 236                                 <term><varname>DirectoryMode=</varname></term>
 237                                 <listitem><para>Directories of mount
 238                                 points (and any parent directories)
 239                                 are automatically created if
 240                                 needed. This option specifies the file
 241                                 system access mode used when creating
 242                                 these directories. Takes an access
 243                                 mode in octal notation. Defaults to
 244                                 0755.</para></listitem>
 245                         </varlistentry>
 246
 247                         <varlistentry>
 248                                 <term><varname>TimeoutSec=</varname></term>
 249                                 <listitem><para>Configures the time to
 250                                 wait for the mount command to
 251                                 finish. If a command does not exit
 252                                 within the configured time, the mount
 253                                 will be considered failed and be shut
 254                                 down again. All commands still running
 255                                 will be terminated forcibly via
 256                                 <constant>SIGTERM</constant>, and after another delay of
 257                                 this time with <constant>SIGKILL</constant>. (See
 258                                 <option>KillMode=</option> in
 259                                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>.)
 260                                 Takes a unit-less value in seconds, or
 261                                 a time span value such as "5min
 262                                 20s". Pass 0 to disable the timeout
 263                                 logic. The default value is set from the manager configuration
 264                                 file's <varname>DefaultTimeoutStart=</varname> variable.</para></listitem>
 265                         </varlistentry>
 266                 </variablelist>
 267
 268                 <para>Check
 269                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 270                 and
 271                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 272                 for more settings.</para>
 273         </refsect1>
 274
 275         <refsect1>
 276                   <title>See Also</title>
 277                   <para>
 278                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 279                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 280                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 281                           <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 282                           <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 283                           <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 284                           <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 285                           <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 286                           <citerefentry><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 287                           <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 288                           <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 289                           <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 290                   </para>
 291         </refsect1>
 292
 293 </refentry>