sysctl.d — Configure kernel parameters at boot
/etc/sysctl.d/*.conf
/run/sysctl.d/*.conf
/usr/lib/sysctl.d/*.conf
systemd uses configuration files from the above directories to configure sysctl(8) kernel parameters during boot.
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 /run/
override files
with the same name in /usr/lib/
.
Files in /etc
override files with
the same name in /run/
and
/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 installed by vendor packages. All
configuration files are sorted by their name in
alphabetical order, regardless in which of the
directories they reside, to guarantee that a specific
configuration file takes precedence over another file
with an alphabetically earlier name, if both files
contain the same variable setting.
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
carrying with the
same name.