limits.conf5Linux-PAM Manuallimits.confconfiguration file for the pam_limits moduleDESCRIPTION
The syntax of the lines is as follows:
<domain><type><item><value>
The fields listed above should be filled as follows:
a username
a groupname, with @group syntax.
This should not be confused with netgroups.
the wildcard *, for default entry.
the wildcard %, for maxlogins limit only,
can also be used with %group syntax.
for enforcing hard resource limits.
These limits are set by the superuser and enforced by the Kernel.
The user cannot raise his requirement of system resources above such values.
for enforcing soft resource limits.
These limits are ones that the user can move up or down within the
permitted range by any pre-existing hard
limits. The values specified with this token can be thought of as
default values, for normal system usage.
for enforcing both soft and
hard resource limits together.
Note, if you specify a type of '-' but neglect to supply the
item and value fields then the module will never enforce any
limits on the specified user/group etc. .
limits the core file size (KB)maximum data size (KB)maximum filesize (KB)maximum locked-in-memory address space (KB)maximum number of open filesmaximum resident set size (KB) (Ignored in Linux 2.4.30 and higher)maximum stack size (KB)maximum CPU time (minutes)maximum number of processesaddress space limit (KB)maximum number of logins for this user except
for this with uid=0maximum number of logins on systemthe priority to run user process with (negative
values boost process priority)maximum locked files (Linux 2.4 and higher)maximum number of pending signals (Linux 2.6 and higher)maximum memory used by POSIX message queues (bytes)
(Linux 2.6 and higher)maximum nice priority allowed to raise to (Linux 2.6.12 and higher) values: [-20,19]maximum realtime priority allowed for non-privileged processes
(Linux 2.6.12 and higher)
All items support the values -1,
unlimited or infinity indicating no limit,
except for priority and nice.
If a hard limit or soft limit of a resource is set to a valid value,
but outside of the supported range of the local system, the system
may reject the new limit or unexpected behavior may occur. If the
control value required is used, the module will
reject the login if a limit could not be set.
In general, individual limits have priority over group limits, so if
you impose no limits for admin group, but one of
the members in this group have a limits line, the user will have its
limits set according to this line.
Also, please note that all limit settings are set
per login. They are not global, nor are they
permanent; existing only for the duration of the session.
In the limits configuration file, the
'#' character introduces a comment
- after which the rest of the line is ignored.
The pam_limits module does report configuration problems
found in its configuration file and errors via syslog3.
EXAMPLES
These are some example lines which might be specified in
/etc/security/limits.conf.
* soft core 0
* hard rss 10000
@student hard nproc 20
@faculty soft nproc 20
@faculty hard nproc 50
ftp hard nproc 0
@student - maxlogins 4
SEE ALSOpam_limits8,
pam.d5,
pam8,
getrlimit2getrlimit3pAUTHOR
pam_limits was initially written by Cristian Gafton <gafton@redhat.com>