sysctl scripts not run at boot time
Sysctl doesn’t seem to run kernel parameters at boot time. Either manually entering “sysctl -p” or running “service sysctl restart” will load the parameters set in /etc/sysctl.conf or under /etc/sysctl.d/
The readme files and https://wiki.alpinelinux.org/wiki/Sysctl.conf seem to indicate that this is not the expected behavior.
(from redmine: issue id 9928, created on 2019-01-27)