I’ve heard of
systemctl, but not
sysctl. I came across this in an awesome blog from from GCP regarding fixing a DNS issue on a VM.
The UDP stack can be configured at kernel level using the sysctl interface.
To configure the kernel runtime, you can use command line options (grub) or the sysctl interface. I look in /etc/sysctl.conf, and lo and behold, there are several custom configurations.
So it seems like
sysctl is an interface for configuring the kernel.
Lets check the man page.
sysctl - configure kernel parameters at runtime
sysctl is used to modify kernel parameters at runtime. The parameters available are those listed under /proc/sys/man sysctl
In the article, the engineer used the following command to change the kernel’s configurations at runtime:
sysctl -w net.core.rmem_default=$((2**31-1))
So it looks like you can use
-w to change a setting.
Much more to look at here, but at least I know what it is.