Sysctl
sysctl is provided by sys-process/procps, and can be used to configure kernel parameters at system runtime.
Introduction
sysctl can be used to manage the system's kernel configuration, available through /proc/sys/.
sysctl parameter names can be found using file paths under /proc/sys/, replacing the "/" with ".".
Installation
Kernel
File systems --->
Pseudo filesystems --->
<*> /proc file system support
Emerge
root #
emerge --ask sys-process/procps
This package is typically installed by default.
Configuration
Kernel parameters can be configured by editing .conf files under /etc/sysctl.d.
Multiple files can be used, but they will be processed in lexicographical order, and values defined multiple times will take the last value. /etc/sysctl.conf is typically loaded last.
Service
OpenRC
The OpenRC sysctl init script is enabled by default, it simply executes sysctl --system.
Systemd
The Systemd systemd-sysctl service is enabled by default.
Usage
Viewing current values
Current kernel configuration values can be printed with:
root #
sysctl --all
Setting values
Values can be updated using:
root #
sysctl --write {parameter}={value}
Setting values this way does not persist across reboots.
Reloading values
Configuration values can be reloaded as they would be read on boot with:
root #
sysctl --system
Filtering values
--pattern can be used to filter to parameters which match the supplied extended regex. This can be used for both printing and setting values.
To reload all system net values:
root #
sysctl --system --pattern 'net.*'