man 8 systemd-sysctl

SYSTEMD-SYSCTL.SERVICE(8)   systemd-sysctl.service   SYSTEMD-SYSCTL.SERVICE(8)

NAME
       systemd-sysctl.service, systemd-sysctl - Configure kernel parameters at
       boot

SYNOPSIS
       /usr/lib/systemd/systemd-sysctl [OPTIONS...] [CONFIGFILE...]

       systemd-sysctl.service

DESCRIPTION
       systemd-sysctl.service is an early boot service that configures
       sysctl(8) kernel parameters by invoking
       /usr/lib/systemd/systemd-sysctl.

       When invoked with no arguments, /usr/lib/systemd/systemd-sysctl applies
       all directives from configuration files listed in sysctl.d(5). If one
       or more filenames are passed on the command line, only the directives
       in these files are applied.

       In addition, --prefix= option may be used to limit which sysctl
       settings are applied.

       See sysctl.d(5) for information about the configuration of sysctl
       settings. After sysctl configuration is changed on disk, it must be
       written to the files in /proc/sys/ before it takes effect. It is
       possible to update specific settings, or simply to reload all
       configuration, see Examples below.

OPTIONS
       --prefix=
           Only apply rules with the specified prefix.

       --strict=
           Always return non-zero exit code on failure (including invalid
           sysctl variable name and insufficient permissions), unless the
           sysctl variable name is prefixed with a "-" character.

       --cat-config
           Copy the contents of config files to standard output. Before each
           file, the filename is printed as a comment.

       --no-pager
           Do not pipe output into a pager.

       -h, --help
           Print a short help text and exit.

       --version
           Print a short version string and exit.

CREDENTIALS
       systemd-sysctl supports the service credentials logic as implemented by
       LoadCredential=/SetCredential= (see systemd.exec(1) for details). The
       following credentials are used when passed in:

       "sysctl.extra"
           The contents of this credential may contain additional lines to
           operate on. The credential contents should follow the same format
           as any other sysctl.d/ drop-in configuration file. If this
           credential is passed it is processed after all of the drop-in files
           read from the file system. The settings configured in the
           credential hence take precedence over those in the file system.

       Note that by default the systemd-sysctl.service unit file is set up to
       inherit the "sysctl.extra" credential from the service manager.

EXAMPLES
       Example 1. Reset all sysctl settings

           systemctl restart systemd-sysctl

       Example 2. View coredump handler configuration

           # sysctl kernel.core_pattern
           kernel.core_pattern = |/usr/libexec/abrt-hook-ccpp %s %c %p %u %g %t %P %I

       Example 3. Update coredump handler configuration

           # /usr/lib/systemd/systemd-sysctl --prefix kernel.core_pattern

       This searches all the directories listed in sysctl.d(5) for
       configuration files and writes /proc/sys/kernel/core_pattern.

       Example 4. Update coredump handler configuration according to a
       specific file

           # /usr/lib/systemd/systemd-sysctl 50-coredump.conf

       This applies all the settings found in 50-coredump.conf. Either
       /etc/sysctl.d/50-coredump.conf, or /run/sysctl.d/50-coredump.conf, or
       /usr/lib/sysctl.d/50-coredump.conf will be used, in the order of
       preference.

       See sysctl(8) for various ways to directly apply sysctl settings.

SEE ALSO
       systemd(1), sysctl.d(5), sysctl(8)

systemd 252                                          SYSTEMD-SYSCTL.SERVICE(8)