| JOURNALD.CONF(5) | journald.conf | JOURNALD.CONF(5) |
.SH "NAME" journald.conf, journald.conf.d, journald@.conf - Journal
service configuration files
.SH "SYNOPSIS"
.PP
.SH "DESCRIPTION"
.PP These files configure various parameters of the systemd journal service,
systemd-journald.service(8). See systemd.syntax(7) for a
general description of the syntax.
.PP The systemd-journald instance managing the default namespace is
configured by /etc/systemd/journald.conf and associated drop-ins. Instances
managing other namespaces read /etc/systemd/journald@NAMESPACE.conf
and associated drop-ins with the namespace identifier filled in. This allows
each namespace to carry a distinct configuration. See
systemd-journald.service(8) for details about journal namespaces.
.SH "CONFIGURATION DIRECTORIES AND PRECEDENCE"
.PP The default configuration is set during compilation, so configuration is
only needed when it is necessary to deviate from those defaults. The main
configuration file is loaded from one of the listed directories in order of
priority, only the first file found is used: /etc/systemd/, /run/systemd/,
/usr/local/lib/systemd/ [1], /usr/lib/systemd/. The vendor version of the
file contains commented out entries showing the defaults as a guide to the
administrator. Local overrides can also be created by creating drop-ins, as
described below. The main configuration file can also be edited for this
purpose (or a copy in /etc/ if it is shipped under /usr/), however using
drop-ins for local configuration is recommended over modifications to the
main configuration file.
.PP In addition to the main configuration file, drop-in configuration
snippets are read from /usr/lib/systemd/*.conf.d/,
/usr/local/lib/systemd/*.conf.d/, and /etc/systemd/*.conf.d/. Those drop-ins
have higher precedence and override the main configuration file. Files in
the *.conf.d/ configuration subdirectories are sorted by their filename in
lexicographic order, regardless of in which of the subdirectories they
reside. When multiple files specify the same option, for options which
accept just a single value, the entry in the file sorted last takes
precedence, and for options which accept a list of values, entries are
collected as they occur in the sorted files.
.PP When packages need to customize the configuration, they can install
drop-ins under /usr/. Files in /etc/ are reserved for the local
administrator, who may use this logic to override the configuration files
installed by vendor packages. Drop-ins have to be used to override package
drop-ins, since the main configuration file has lower precedence. It is
recommended to prefix all filenames in those subdirectories with a two-digit
number and a dash, to simplify the ordering. This also defines a concept of
drop-in priorities to allow OS vendors to ship drop-ins within a specific
range lower than the range used by users. This should lower the risk of
package drop-ins overriding accidentally drop-ins defined by users. It is
recommended to use the range 10-40 for drop-ins in /usr/ and the range 60-90
for drop-ins in /etc/ and /run/, to make sure that local and transient
drop-ins take priority over drop-ins shipped by the OS vendor.
.PP To disable a configuration file supplied by the vendor, the recommended
way is to place a symlink to /dev/null in the configuration directory in
/etc/, with the same filename as the vendor configuration file.
.SH "OPTIONS"
.PP All options are configured in the [Journal] section:
.PP Storage=
Controls where to store journal data. One of volatile, persistent, auto and
none. If volatile, journal log data will be stored only in memory, i.e.
below the /run/log/journal hierarchy (which is created if needed). If
persistent, data will be stored preferably on disk, i.e. below the
/var/log/journal hierarchy (which is created if needed), with a fallback to
/run/log/journal (which is created if needed), during early boot and if the
disk is not writable. auto behaves like persistent if the /var/log/journal
directory exists, and volatile otherwise (the existence of the directory
controls the storage mode). none turns off all storage, all log data
received will be dropped (but forwarding to other targets, such as the
console, the kernel log buffer, or a syslog socket will still work).
Defaults to persistent in the default journal namespace (this value is
determined at compilation time), and persistent in all others.
Note that journald will initially use volatile storage, until a call to
journalctl --flush (or sending SIGUSR1 to journald) will cause
it to switch to persistent logging (under the conditions mentioned above).
This is done automatically on boot via systemd-journal-flush.service.
Note that when this option is changed to volatile, existing persistent data
is not removed. In the other direction, journalctl(1) with the
--flush option may be used to move volatile data to persistent
storage.
When journal namespacing (see LogNamespace= in systemd.exec(5))
is used, setting Storage= to volatile or auto will not have an effect
on the creation of the per-namespace logs directory in /var/log/journal/, as
the systemd-journald@.service service file by default carries
LogsDirectory=. To turn that off, add a unit file drop-in file that
sets LogsDirectory= to an empty string.
Note that per-user journal files are not supported unless persistent storage
is enabled, thus making journalctl --user unavailable.
The storage to use can also be specified via the journal.storage credential.
Values configured via configuration files take priority over values
configured via the credential.
Added in version 186.
.RE
.PP Compress=
Can take a boolean value. If enabled (the default), data objects that shall
be stored in the journal and are larger than the default threshold of 512
bytes are compressed before they are written to the file system. It can also
be set to a number of bytes to specify the compression threshold directly.
Suffixes like K, M, and G can be used to specify larger units.
.RE
.PP Seal=
Takes a boolean value. If enabled (the default), and a sealing key is
available (as created by journalctl(1)'s --setup-keys
command), Forward Secure Sealing (FSS) for all persistent journal files is
enabled. FSS is based on Seekable Sequential Key Generators[2] by G.
A. Marson and B. Poettering (doi:10.1007/978-3-642-40203-6_7) and may be
used to protect journal files from unnoticed alteration.
Added in version 189.
.RE
.PP SplitMode=
Controls whether to split up journal files per user, either uid or none.
Split journal files are primarily useful for access control: on UNIX/Linux
access control is managed per file, and the journal daemon will assign users
read access to their journal files. If uid, all regular users (with UID
outside the range of system users, dynamic service users, and the nobody
user) will each get their own journal files, and system users will log to
the system journal. See Users, Groups, UIDs and GIDs on systemd
systems[3] for more details about UID ranges. If none, journal files are
not split up by user and all messages are instead stored in the single
system journal. In this mode unprivileged users generally do not have access
to their own log data. Note that splitting up journal files by user is only
available for journals stored persistently. If journals are stored on
volatile storage (see Storage= above), only a single journal file is
used. Defaults to uid.
Added in version 190.
.RE
.PP RateLimitIntervalSec=, RateLimitBurst=
Configures the rate limiting that is applied to all messages generated on the
system. If, in the time interval defined by RateLimitIntervalSec=,
more messages than specified in RateLimitBurst= are logged by a
service, all further messages within the interval are dropped until the
interval is over. A message about the number of dropped messages is
generated. This rate limiting is applied per-service, so that two services
which log do not interfere with each other's limits. Defaults to 10000
messages in 30s. The time specification for RateLimitIntervalSec= may
be specified in the following units: s, min, h, ms, us. To turn off any kind
of rate limiting, set either value to 0.
Note that the effective rate limit is multiplied by a factor derived from the
available free disk space for the journal. Currently, this factor is
calculated using the base 2 logarithm.
.sp
Table 1. Example RateLimitBurst= rate modifications by
the available disk space
| Available Disk Space | Burst Multiplier |
| <= 1MB | 1 |
| <= 16MB | 2 |
| <= 256MB | 3 |
| <= 4GB | 4 |
| <= 64GB | 5 |
| <= 1TB | 6 |
If a service provides rate limits for itself through
LogRateLimitIntervalSec= and/or LogRateLimitBurst= in
systemd.exec(5), those values will override the settings specified
here.
.RE
.PP SystemMaxUse=, SystemKeepFree=, SystemMaxFileSize=,
SystemMaxFiles=, RuntimeMaxUse=, RuntimeKeepFree=,
RuntimeMaxFileSize=, RuntimeMaxFiles=
Enforce size limits on the journal files stored. The options prefixed with
System apply to the journal files when stored on a persistent file system,
more specifically /var/log/journal. The options prefixed with Runtime apply
to the journal files when stored on a volatile in-memory file system, more
specifically /run/log/journal. The former is used only when /var/ is
mounted, writable, and the directory /var/log/journal exists. Otherwise,
only the latter applies. Note that this means that during early boot and if
the administrator disabled persistent logging, only the latter options
apply, while the former apply if persistent logging is enabled and the
system is fully booted up. journalctl and systemd-journald
ignore all files with names not ending with .journal or .journal~, so only
such files, located in the appropriate directories, are taken into account
when calculating current disk usage.
SystemMaxUse= and RuntimeMaxUse= control how much disk space
the journal may use up at most. SystemKeepFree= and
RuntimeKeepFree= control how much disk space systemd-journald shall
leave free for other uses. systemd-journald will respect both limits
and use the smaller of the two values.
The first pair defaults to 10% and the second to 15% of the size of the
respective file system, but each of the calculated default values is capped
to 4G. If the file system is nearly full and either SystemKeepFree=
or RuntimeKeepFree= are violated when systemd-journald is started,
the limit will be raised to the percentage that is actually free. This means
that if there was enough free space before and journal files were created,
and subsequently something else causes the file system to fill up, journald
will stop using more space, but it will not be removing existing files to
reduce the footprint again, either. Also note that only archived files are
deleted to reduce the space occupied by journal files. This means that, in
effect, there might still be more space used than SystemMaxUse= or
RuntimeMaxUse= limit after a vacuuming operation is complete.
SystemMaxFileSize= and RuntimeMaxFileSize= control how large
individual journal files may grow at most. This influences the granularity
in which disk space is made available through rotation, i.e. deletion of
historic data. Defaults to one eighth of the values configured with
SystemMaxUse= and RuntimeMaxUse= capped to 128M, so that
usually seven rotated journal files are kept as history. If the journal
compact mode is enabled (enabled by default), the maximum file size is
capped to 4G.
Specify values in bytes or use K, M, G, T, P, E as units for the specified
sizes (equal to 1024, 1024², ... bytes). Note that size limits are
enforced synchronously when journal files are extended, and no explicit
rotation step triggered by time is needed.
SystemMaxFiles= and RuntimeMaxFiles= control how many
individual journal files to keep at most. Note that only archived files are
deleted to reduce the number of files until this limit is reached; active
files will stay around. This means that, in effect, there might still be
more journal files around in total than this limit after a vacuuming
operation is complete. This setting defaults to 100.
.RE
.PP MaxFileSec=
The maximum time to store entries in a single journal file before rotating to
the next one. Normally, time-based rotation should not be required as
size-based rotation with options such as SystemMaxFileSize= should be
sufficient to ensure that journal files do not grow without bounds. However,
to ensure that not too much data is lost at once when old journal files are
deleted, it might make sense to change this value from the default of one
month. Set to 0 to turn off this feature. This setting takes time values
which may be suffixed with the units year, month, week, day, h or m to
override the default time unit of seconds.
Added in version 195.
.RE
.PP MaxRetentionSec=
The maximum time to store journal entries. This controls whether journal
files containing entries older than the specified time span are deleted.
Normally, time-based deletion of old journal files should not be required as
size-based deletion with options such as SystemMaxUse= should be
sufficient to ensure that journal files do not grow without bounds. However,
to enforce data retention policies, it might make sense to change this value
from the default of 0 (which turns off this feature). This setting also
takes time values which may be suffixed with the units year, month, week,
day, h or m to override the default time unit of seconds.
Added in version 195.
.RE
.PP SyncIntervalSec=
The timeout before synchronizing journal files to disk. After syncing,
journal files are placed in the OFFLINE state. Note that syncing is
unconditionally done immediately after a log message of priority CRIT, ALERT
or EMERG has been logged. This setting hence applies only to messages of the
levels ERR, WARNING, NOTICE, INFO, DEBUG. The default timeout is 5
minutes.
Added in version 199.
.RE
.PP ForwardToSyslog=, ForwardToKMsg=, ForwardToConsole=,
ForwardToWall=, ForwardToSocket=
Control whether log messages received by the journal daemon shall be
forwarded to a traditional syslog daemon, to the kernel log buffer (kmsg),
to the system console, sent as wall messages to all logged-in users or sent
over a socket. These options take boolean arguments except for
ForwardToSocket= which takes an address instead. If forwarding to syslog is
enabled but nothing reads messages from the socket, forwarding to syslog has
no effect. By default, only forwarding to wall is enabled. These settings
may be overridden at boot time with the kernel command line options
systemd.journald.forward_to_syslog, systemd.journald.forward_to_kmsg,
systemd.journald.forward_to_console, and systemd.journald.forward_to_wall.
If the option name is specified without = and the following argument, true
is assumed. Otherwise, the argument is parsed as a boolean.
The socket forwarding address can be specified with the credential
journal.forward_to_socket. The following socket types are supported:
AF_INET (e.g. 192.168.0.11:4444), AF_INET6 (e.g.
[2001:db8::ff00:42:8329]:4444), AF_UNIX (e.g.
/run/host/journal/socket), AF_VSOCK (e.g. vsock:2:1234)
When forwarding to the console, the TTY to log to can be changed with
TTYPath=, described below.
When forwarding to the kernel log buffer (kmsg), make sure to select a
suitably large size for the log buffer, for example by adding log_buf_len=8M
to the kernel command line. systemd will automatically disable
kernel's rate-limiting applied to userspace processes (equivalent to setting
printk.devkmsg=on).
When forwarding over a socket the Journal Export Format[4] is used
when sending over the wire. Notably this includes the metadata field
__REALTIME_TIMESTAMP so that systemd-journal-remote (see
systemd-journal-remote.service(8)) can be used to receive the
forwarded journal entries.
Note: Forwarding is performed synchronously within journald, and may
significantly affect its performance. This is particularly relevant when
using ForwardToConsole=yes in cloud environments, where the console is often
a slow, virtual serial port. Since journald is implemented as a conventional
single-process daemon, forwarding to a completely hung console will block
journald. This can have a cascading effect resulting in any services
synchronously logging to the blocked journal also becoming blocked. Unless
actively debugging/developing something, it is generally preferable to setup
a journalctl --follow style service redirected to the console,
instead of ForwardToConsole=yes, for production use.
.PP Note: Using ForwardToSocket= over IPv4/IPv6 links can be very slow
due to the synchronous nature of the sockets. Take care to ensure your link
is a low-latency local link if possible. Typically IP networking is not
available everywhere journald runs, e.g. in the initrd during boot. Consider
using AF_VSOCK/AF_UNIX sockets for this if possible.
.RE
.PP MaxLevelStore=, MaxLevelSyslog=, MaxLevelKMsg=,
MaxLevelConsole=, MaxLevelWall=, MaxLevelSocket=
Controls the maximum log level of messages that are stored in the journal,
forwarded to syslog, kmsg, the console, the wall, or a socket (if that is
enabled, see above). As argument, takes one of emerg, alert, crit, err,
warning, notice, info, debug, or integer values in the range of 0–7
(corresponding to the same levels). Messages equal or below the log level
specified are stored/forwarded, messages above are dropped. Defaults to
debug for MaxLevelStore=, MaxLevelSyslog= and
MaxLevelSocket=, to ensure that the all messages are stored in the
journal, forwarded to syslog and the socket if one exists. Defaults to
notice for MaxLevelKMsg=, info for MaxLevelConsole=, and emerg
for MaxLevelWall=. These settings may be overridden at boot time with
the kernel command line options systemd.journald.max_level_store=,
systemd.journald.max_level_syslog=, systemd.journald.max_level_kmsg=,
systemd.journald.max_level_console=, systemd.journald.max_level_wall=,
systemd.journald.max_level_socket=.
Added in version 185.
.RE
.PP ReadKMsg=
Takes a boolean value. If enabled systemd-journal processes /dev/kmsg
messages generated by the kernel. In the default journal namespace this
option is enabled by default, it is disabled in all others.
Added in version 235.
.RE
.PP Audit=
Takes a boolean value or special value keep. If enabled
systemd-journald will turn on kernel auditing on start-up. If
disabled it will turn it off. When keep it will neither enable nor disable
it, leaving the previous state unchanged. This means if another tool turns
on auditing even if systemd-journald left it off, it will still
collect the generated messages. Defaults to yes in the default journal
namespace, and keep otherwise.
Note that this option does not control whether systemd-journald
collects generated audit records, it just controls whether it tells the
kernel to generate them. If you need to prevent systemd-journald from
collecting the generated messages, the socket unit
systemd-journald-audit.socket can be disabled and, in this case, this
setting is without effect.
Added in version 246.
.RE
.PP TTYPath=
Change the console TTY to use if ForwardToConsole=yes is used.
Defaults to /dev/console.
Added in version 185.
.RE
.PP LineMax=
The maximum line length to permit when converting stream logs into record
logs. When a systemd unit's standard output/error are connected to the
journal via a stream socket, the data read is split into individual log
records at newline (\n, ASCII 10) and NUL characters. If no such
delimiter is read for the specified number of bytes a hard log record
boundary is artificially inserted, breaking up overly long lines into
multiple log records. Selecting overly large values increases the possible
memory usage of the Journal daemon for each stream client, as in the worst
case the journal daemon needs to buffer the specified number of bytes in
memory before it can flush a new log record to disk. Also note that
permitting overly large line maximum line lengths affects compatibility with
traditional log protocols as log records might not fit anymore into a single
AF_UNIX or AF_INET datagram. Takes a size in bytes. If the
value is suffixed with K, M, G or T, the specified size is parsed as
Kilobytes, Megabytes, Gigabytes, or Terabytes (with the base 1024),
respectively. Defaults to 48K, which is relatively large but still small
enough so that log records likely fit into network datagrams along with
extra room for metadata. Note that values below 79 are not accepted and will
be bumped to 79.
Added in version 235.
.RE
.SH "FORWARDING TO TRADITIONAL SYSLOG DAEMONS"
.PP Journal events can be transferred to a different logging daemon in two
different ways. With the first method, messages are immediately forwarded to
a socket (/run/systemd/journal/syslog), where the traditional syslog daemon
can read them. This method is controlled by the ForwardToSyslog=
option. With a second method, a syslog daemon behaves like a normal journal
client, and reads messages from the journal files, similarly to
journalctl(1). With this, messages do not have to be read
immediately, which allows a logging daemon which is only started late in
boot to access all messages since the start of the system. In addition, full
structured meta-data is available to it. This method of course is available
only if the messages are stored in a journal file at all. So it will not
work if Storage=none is set. It should be noted that usually the
second method is used by syslog daemons, so the Storage=
option, and not the ForwardToSyslog= option, is relevant for
them.
.SH "SEE ALSO"
.PP systemd(1), systemd-journald.service(8),
journalctl(1), systemd.journal-fields(7),
systemd-system.conf(5)
NOTES
- 1.
-
💣💥🧨💥💥💣 Please note that those configuration files must be available at all times. If /usr/local/ is a separate partition, it may not be available during early boot, and must not be used for configuration. - 2.
- Seekable Sequential Key Generators
- 3.
- Users, Groups, UIDs and GIDs on systemd systems
- 4.
- Journal Export Format
| systemd 262.2 |