SYSCTL.D(5)sysctl.dSYSCTL.D(5)NAMEsysctl.d - Configure kernel parameters at boot
SYNOPSIS
/etc/sysctl.d/*.conf
/run/sysctl.d/*.conf
/usr/lib/sysctl.d/*.conf
DESCRIPTION
At boot, systemd-sysctl.service(8) reads configuration files from the
above directories to configure sysctl(8) kernel parameters.
CONFIGURATION FORMAT
The configuration files contain a list of variable assignments,
separated by newlines. Empty lines and lines whose first non-whitespace
character is # or ; are ignored.
Note that both / and . are accepted as label separators within sysctl
variable names. "kernel.domainname=foo" and "kernel/domainname=foo"
hence are entirely equivalent.
Each configuration file shall be named in the style of program.conf.
Files in /etc/ override files with the same name in /usr/lib/ and
/run/. Files in /run/ override files with the same name in /usr/lib/.
Packages should install their configuration files in /usr/lib/. Files
in /etc/ are reserved for the local administrator, who may use this
logic to override the configuration files installed by vendor packages.
All configuration files are sorted by their filename in lexicographic
order, regardless of which of the directories they reside in. If
multiple files specify the same variable name, the entry in the file
with the lexicographically latest name will be applied. It is
recommended to prefix all filenames with a two-digit number and a dash,
to simplify the ordering of the files.
If the administrator wants to disable a configuration file supplied by
the vendor, the recommended way is to place a symlink to /dev/null in
/etc/sysctl.d/ bearing the same filename.
The settings configured with sysctl.d files will be applied early on
boot. The network interface-specific options will also be applied
individually for each network interface as it shows up in the system.
(More specifically, that is net.ipv4.conf.*, net.ipv6.conf.*,
net.ipv4.neigh.* and net.ipv6.neigh.*)
EXAMPLE
Example 1. /etc/sysctl.d/domain-name.conf example:
# Set kernel YP domain name
kernel.domainname=example.com
SEE ALSOsystemd(1), systemd-sysctl.service(8), systemd-delta(1), sysctl(8),
sysctl.conf(5)systemd 212SYSCTL.D(5)