man/journald.conf.xml

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   8
   9 <refentry id="journald.conf"
  10     xmlns:xi="http://www.w3.org/2001/XInclude">
  11   <refentryinfo>
  12     <title>journald.conf</title>
  13     <productname>systemd</productname>
  14   </refentryinfo>
  15
  16   <refmeta>
  17     <refentrytitle>journald.conf</refentrytitle>
  18     <manvolnum>5</manvolnum>
  19   </refmeta>
  20
  21   <refnamediv>
  22     <refname>journald.conf</refname>
  23     <refname>journald.conf.d</refname>
  24     <refpurpose>Journal service configuration files</refpurpose>
  25   </refnamediv>
  26
  27   <refsynopsisdiv>
  28     <para><filename>/etc/systemd/journald.conf</filename></para>
  29     <para><filename>/etc/systemd/journald.conf.d/*.conf</filename></para>
  30     <para><filename>/run/systemd/journald.conf.d/*.conf</filename></para>
  31     <para><filename>/usr/lib/systemd/journald.conf.d/*.conf</filename></para>
  32   </refsynopsisdiv>
  33
  34   <refsect1>
  35     <title>Description</title>
  36
  37     <para>These files configure various parameters of the systemd journal service,
  38     <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
  39     See
  40     <citerefentry><refentrytitle>systemd.syntax</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  41     for a general description of the syntax.</para>
  42
  43   </refsect1>
  44
  45   <xi:include href="standard-conf.xml" xpointer="main-conf" />
  46
  47   <refsect1>
  48     <title>Options</title>
  49
  50     <para>All options are configured in the
  51     <literal>[Journal]</literal> section:</para>
  52
  53     <variablelist>
  54
  55       <varlistentry>
  56         <term><varname>Storage=</varname></term>
  57
  58         <listitem><para>Controls where to store journal data. One of
  59         <literal>volatile</literal>,
  60         <literal>persistent</literal>,
  61         <literal>auto</literal> and
  62         <literal>none</literal>. If
  63         <literal>volatile</literal>, journal
  64         log data will be stored only in memory, i.e. below the
  65         <filename>/run/log/journal</filename> hierarchy (which is
  66         created if needed). If <literal>persistent</literal>, data
  67         will be stored preferably on disk, i.e. below the
  68         <filename>/var/log/journal</filename> hierarchy (which is
  69         created if needed), with a fallback to
  70         <filename>/run/log/journal</filename> (which is created if
  71         needed), during early boot and if the disk is not writable.
  72         <literal>auto</literal> is similar to
  73         <literal>persistent</literal> but the directory
  74         <filename>/var/log/journal</filename> is not created if
  75         needed, so that its existence controls where log data goes.
  76         <literal>none</literal> turns off all storage, all log data
  77         received will be dropped. Forwarding to other targets, such as
  78         the console, the kernel log buffer, or a syslog socket will
  79         still work however. Defaults to
  80         <literal>auto</literal>.</para></listitem>
  81       </varlistentry>
  82
  83       <varlistentry>
  84         <term><varname>Compress=</varname></term>
  85
  86         <listitem><para>Can take a boolean value. If enabled (the
  87         default), data objects that shall be stored in the journal
  88         and are larger than the default threshold of 512 bytes are
  89         compressed before they are written to the file system. It
  90         can also be set to a number of bytes to specify the
  91         compression threshold directly. Suffixes like K, M, and G
  92         can be used to specify larger units.</para></listitem>
  93       </varlistentry>
  94
  95       <varlistentry>
  96         <term><varname>Seal=</varname></term>
  97
  98         <listitem><para>Takes a boolean value. If enabled (the
  99         default), and a sealing key is available (as created by
 100         <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
 101         <option>--setup-keys</option> command), Forward Secure Sealing
 102         (FSS) for all persistent journal files is enabled. FSS is
 103         based on <ulink
 104         url="https://eprint.iacr.org/2013/397">Seekable Sequential Key
 105         Generators</ulink> by G. A. Marson and B. Poettering
 106         (doi:10.1007/978-3-642-40203-6_7) and may be used to protect
 107         journal files from unnoticed alteration.</para></listitem>
 108       </varlistentry>
 109
 110       <varlistentry>
 111         <term><varname>SplitMode=</varname></term>
 112
 113         <listitem><para>Controls whether to split up journal files per user, either <literal>uid</literal> or
 114         <literal>none</literal>. Split journal files are primarily useful for access control: on UNIX/Linux access
 115         control is managed per file, and the journal daemon will assign users read access to their journal files. If
 116         <literal>uid</literal>, all regular users will each get their own journal files, and system users will log to
 117         the system journal. If <literal>none</literal>, journal files are not split up by user and all messages are
 118         instead stored in the single system journal. In this mode unprivileged users generally do not have access to
 119         their own log data. Note that splitting up journal files by user is only available for journals stored
 120         persistently. If journals are stored on volatile storage (see <varname>Storage=</varname> above), only a single
 121         journal file is used. Defaults to <literal>uid</literal>.</para></listitem>
 122       </varlistentry>
 123
 124       <varlistentry>
 125         <term><varname>RateLimitIntervalSec=</varname></term>
 126         <term><varname>RateLimitBurst=</varname></term>
 127
 128         <listitem><para>Configures the rate limiting that is applied
 129         to all messages generated on the system. If, in the time
 130         interval defined by <varname>RateLimitIntervalSec=</varname>,
 131         more messages than specified in
 132         <varname>RateLimitBurst=</varname> are logged by a service,
 133         all further messages within the interval are dropped until the
 134         interval is over. A message about the number of dropped
 135         messages is generated. This rate limiting is applied
 136         per-service, so that two services which log do not interfere
 137         with each other's limits. Defaults to 10000 messages in 30s.
 138         The time specification for
 139         <varname>RateLimitIntervalSec=</varname> may be specified in the
 140         following units: <literal>s</literal>, <literal>min</literal>,
 141         <literal>h</literal>, <literal>ms</literal>,
 142         <literal>us</literal>. To turn off any kind of rate limiting,
 143         set either value to 0.</para></listitem>
 144       </varlistentry>
 145
 146       <varlistentry>
 147         <term><varname>SystemMaxUse=</varname></term>
 148         <term><varname>SystemKeepFree=</varname></term>
 149         <term><varname>SystemMaxFileSize=</varname></term>
 150         <term><varname>SystemMaxFiles=</varname></term>
 151         <term><varname>RuntimeMaxUse=</varname></term>
 152         <term><varname>RuntimeKeepFree=</varname></term>
 153         <term><varname>RuntimeMaxFileSize=</varname></term>
 154         <term><varname>RuntimeMaxFiles=</varname></term>
 155
 156         <listitem><para>Enforce size limits on the journal files
 157         stored. The options prefixed with <literal>System</literal>
 158         apply to the journal files when stored on a persistent file
 159         system, more specifically
 160         <filename>/var/log/journal</filename>. The options prefixed
 161         with <literal>Runtime</literal> apply to the journal files
 162         when stored on a volatile in-memory file system, more
 163         specifically <filename>/run/log/journal</filename>. The former
 164         is used only when <filename>/var</filename> is mounted,
 165         writable, and the directory
 166         <filename>/var/log/journal</filename> exists. Otherwise, only
 167         the latter applies. Note that this means that during early
 168         boot and if the administrator disabled persistent logging,
 169         only the latter options apply, while the former apply if
 170         persistent logging is enabled and the system is fully booted
 171         up. <command>journalctl</command> and
 172         <command>systemd-journald</command> ignore all files with
 173         names not ending with <literal>.journal</literal> or
 174         <literal>.journal~</literal>, so only such files, located in
 175         the appropriate directories, are taken into account when
 176         calculating current disk usage.</para>
 177
 178         <para><varname>SystemMaxUse=</varname> and
 179         <varname>RuntimeMaxUse=</varname> control how much disk space
 180         the journal may use up at most.
 181         <varname>SystemKeepFree=</varname> and
 182         <varname>RuntimeKeepFree=</varname> control how much disk
 183         space systemd-journald shall leave free for other uses.
 184         <command>systemd-journald</command> will respect both limits
 185         and use the smaller of the two values.</para>
 186
 187         <para>The first pair defaults to 10% and the second to 15% of
 188         the size of the respective file system, but each value is
 189         capped to 4G. If the file system is nearly full and either
 190         <varname>SystemKeepFree=</varname> or
 191         <varname>RuntimeKeepFree=</varname> are violated when
 192         systemd-journald is started, the limit will be raised to the
 193         percentage that is actually free. This means that if there was
 194         enough free space before and journal files were created, and
 195         subsequently something else causes the file system to fill up,
 196         journald will stop using more space, but it will not be
 197         removing existing files to reduce the footprint again,
 198         either.</para>
 199
 200         <para><varname>SystemMaxFileSize=</varname> and
 201         <varname>RuntimeMaxFileSize=</varname> control how large
 202         individual journal files may grow at most. This influences
 203         the granularity in which disk space is made available through
 204         rotation, i.e. deletion of historic data. Defaults to one
 205         eighth of the values configured with
 206         <varname>SystemMaxUse=</varname> and
 207         <varname>RuntimeMaxUse=</varname>, so that usually seven
 208         rotated journal files are kept as history.</para>
 209
 210         <para>Specify values in bytes or use K, M, G, T, P, E as
 211         units for the specified sizes (equal to 1024, 1024², … bytes).
 212         Note that size limits are enforced synchronously when journal
 213         files are extended, and no explicit rotation step triggered by
 214         time is needed.</para>
 215
 216         <para><varname>SystemMaxFiles=</varname> and
 217         <varname>RuntimeMaxFiles=</varname> control how many
 218         individual journal files to keep at most. Note that only
 219         archived files are deleted to reduce the number of files until
 220         this limit is reached; active files will stay around. This
 221         means that, in effect, there might still be more journal files
 222         around in total than this limit after a vacuuming operation is
 223         complete. This setting defaults to 100.</para></listitem>
 224       </varlistentry>
 225
 226       <varlistentry>
 227         <term><varname>MaxFileSec=</varname></term>
 228
 229         <listitem><para>The maximum time to store entries in a single
 230         journal file before rotating to the next one. Normally,
 231         time-based rotation should not be required as size-based
 232         rotation with options such as
 233         <varname>SystemMaxFileSize=</varname> should be sufficient to
 234         ensure that journal files do not grow without bounds. However,
 235         to ensure that not too much data is lost at once when old
 236         journal files are deleted, it might make sense to change this
 237         value from the default of one month. Set to 0 to turn off this
 238         feature. This setting takes time values which may be suffixed
 239         with the units <literal>year</literal>,
 240         <literal>month</literal>, <literal>week</literal>,
 241         <literal>day</literal>, <literal>h</literal> or
 242         <literal>m</literal> to override the default time unit of
 243         seconds.</para></listitem>
 244       </varlistentry>
 245
 246       <varlistentry>
 247         <term><varname>MaxRetentionSec=</varname></term>
 248
 249         <listitem><para>The maximum time to store journal entries.
 250         This controls whether journal files containing entries older
 251         then the specified time span are deleted. Normally, time-based
 252         deletion of old journal files should not be required as
 253         size-based deletion with options such as
 254         <varname>SystemMaxUse=</varname> should be sufficient to
 255         ensure that journal files do not grow without bounds. However,
 256         to enforce data retention policies, it might make sense to
 257         change this value from the default of 0 (which turns off this
 258         feature). This setting also takes time values which may be
 259         suffixed with the units <literal>year</literal>,
 260         <literal>month</literal>, <literal>week</literal>,
 261         <literal>day</literal>, <literal>h</literal> or <literal>
 262         m</literal> to override the default time unit of
 263         seconds.</para></listitem>
 264       </varlistentry>
 265
 266       <varlistentry>
 267         <term><varname>SyncIntervalSec=</varname></term>
 268
 269         <listitem><para>The timeout before synchronizing journal files
 270         to disk. After syncing, journal files are placed in the
 271         OFFLINE state. Note that syncing is unconditionally done
 272         immediately after a log message of priority CRIT, ALERT or
 273         EMERG has been logged. This setting hence applies only to
 274         messages of the levels ERR, WARNING, NOTICE, INFO, DEBUG. The
 275         default timeout is 5 minutes. </para></listitem>
 276       </varlistentry>
 277
 278       <varlistentry>
 279         <term><varname>ForwardToSyslog=</varname></term>
 280         <term><varname>ForwardToKMsg=</varname></term>
 281         <term><varname>ForwardToConsole=</varname></term>
 282         <term><varname>ForwardToWall=</varname></term>
 283
 284         <listitem><para>Control whether log messages received by the journal daemon shall
 285         be forwarded to a traditional syslog daemon, to the kernel log buffer (kmsg), to
 286         the system console, or sent as wall messages to all logged-in users.  These
 287         options take boolean arguments. If forwarding to syslog is enabled but nothing
 288         reads messages from the socket, forwarding to syslog has no effect. By default,
 289         only forwarding to wall is enabled. These settings may be overridden at boot time
 290         with the kernel command line options
 291         <literal>systemd.journald.forward_to_syslog</literal>,
 292         <literal>systemd.journald.forward_to_kmsg</literal>,
 293         <literal>systemd.journald.forward_to_console</literal>, and
 294         <literal>systemd.journald.forward_to_wall</literal>. If the option name is
 295         specified without <literal>=</literal> and the following argument, true is
 296         assumed. Otherwise, the argument is parsed as a boolean. When forwarding to the
 297         console, the TTY to log to can be changed with <varname>TTYPath=</varname>,
 298         described below.</para></listitem>
 299       </varlistentry>
 300
 301       <varlistentry>
 302         <term><varname>MaxLevelStore=</varname></term>
 303         <term><varname>MaxLevelSyslog=</varname></term>
 304         <term><varname>MaxLevelKMsg=</varname></term>
 305         <term><varname>MaxLevelConsole=</varname></term>
 306         <term><varname>MaxLevelWall=</varname></term>
 307
 308         <listitem><para>Controls the maximum log level of messages
 309         that are stored on disk, forwarded to syslog, kmsg, the
 310         console or wall (if that is enabled, see above). As argument,
 311         takes one of
 312         <literal>emerg</literal>,
 313         <literal>alert</literal>,
 314         <literal>crit</literal>,
 315         <literal>err</literal>,
 316         <literal>warning</literal>,
 317         <literal>notice</literal>,
 318         <literal>info</literal>,
 319         <literal>debug</literal>,
 320         or integer values in the range of 0–7 (corresponding to the
 321         same levels). Messages equal or below the log level specified
 322         are stored/forwarded, messages above are dropped. Defaults to
 323         <literal>debug</literal> for <varname>MaxLevelStore=</varname>
 324         and <varname>MaxLevelSyslog=</varname>, to ensure that the all
 325         messages are written to disk and forwarded to syslog. Defaults
 326         to
 327         <literal>notice</literal> for <varname>MaxLevelKMsg=</varname>,
 328         <literal>info</literal> for <varname>MaxLevelConsole=</varname>,
 329         and <literal>emerg</literal> for
 330         <varname>MaxLevelWall=</varname>. These settings may be
 331         overridden at boot time with the kernel command line options
 332         <literal>systemd.journald.max_level_store=</literal>,
 333         <literal>systemd.journald.max_level_syslog=</literal>,
 334         <literal>systemd.journald.max_level_kmsg=</literal>,
 335         <literal>systemd.journald.max_level_console=</literal>,
 336         <literal>systemd.journald.max_level_wall=</literal>.</para>
 337         </listitem>
 338       </varlistentry>
 339
 340       <varlistentry>
 341         <term><varname>ReadKMsg=</varname></term>
 342
 343         <listitem><para>Takes a boolean value. If enabled (the
 344         default), journal reads <filename>/dev/kmsg</filename>
 345         messages generated by the kernel.</para></listitem>
 346       </varlistentry>
 347
 348       <varlistentry>
 349         <term><varname>TTYPath=</varname></term>
 350
 351         <listitem><para>Change the console TTY to use if
 352         <varname>ForwardToConsole=yes</varname> is used. Defaults to
 353         <filename>/dev/console</filename>.</para></listitem>
 354       </varlistentry>
 355
 356       <varlistentry>
 357         <term><varname>LineMax=</varname></term>
 358
 359         <listitem><para>The maximum line length to permit when converting stream logs into record logs. When a systemd
 360         unit's standard output/error are connected to the journal via a stream socket, the data read is split into
 361         individual log records at newline (<literal>\n</literal>, ASCII 10) and NUL characters. If no such delimiter is
 362         read for the specified number of bytes a hard log record boundary is artificially inserted, breaking up overly
 363         long lines into multiple log records. Selecting overly large values increases the possible memory usage of the
 364         Journal daemon for each stream client, as in the worst case the journal daemon needs to buffer the specified
 365         number of bytes in memory before it can flush a new log record to disk. Also note that permitting overly large
 366         line maximum line lengths affects compatibility with traditional log protocols as log records might not fit
 367         anymore into a single <constant>AF_UNIX</constant> or <constant>AF_INET</constant> datagram. Takes a size in
 368         bytes. If the value is suffixed with K, M, G or T, the specified size is parsed as Kilobytes, Megabytes,
 369         Gigabytes, or Terabytes (with the base 1024), respectively. Defaults to 48K, which is relatively large but
 370         still small enough so that log records likely fit into network datagrams along with extra room for
 371         metadata. Note that values below 79 are not accepted and will be bumped to 79.</para></listitem>
 372       </varlistentry>
 373
 374     </variablelist>
 375
 376   </refsect1>
 377
 378   <refsect1>
 379     <title>Forwarding to traditional syslog daemons</title>
 380
 381     <para>
 382       Journal events can be transferred to a different logging daemon
 383       in two different ways. With the first method, messages are
 384       immediately forwarded to a socket
 385       (<filename>/run/systemd/journal/syslog</filename>), where the
 386       traditional syslog daemon can read them. This method is
 387       controlled by the <varname>ForwardToSyslog=</varname> option. With a
 388       second method, a syslog daemon behaves like a normal journal
 389       client, and reads messages from the journal files, similarly to
 390       <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
 391       With this, messages do not have to be read immediately,
 392       which allows a logging daemon which is only started late in boot
 393       to access all messages since the start of the system. In
 394       addition, full structured meta-data is available to it. This
 395       method of course is available only if the messages are stored in
 396       a journal file at all. So it will not work if
 397       <varname>Storage=none</varname> is set. It should be noted that
 398       usually the <emphasis>second</emphasis> method is used by syslog
 399       daemons, so the <varname>Storage=</varname> option, and not the
 400       <varname>ForwardToSyslog=</varname> option, is relevant for them.
 401     </para>
 402   </refsect1>
 403
 404   <refsect1>
 405       <title>See Also</title>
 406       <para>
 407         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 408         <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 409         <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 410         <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 411         <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 412       </para>
 413   </refsect1>
 414
 415 </refentry>