wireguard now built into CentOS 7 and CentOS 8's "kernel-plus" kernel

["Jason A. Donenfeld" <Jason@zx2c4.com>]

Hi folks,

Users of RHEL and CentOS have typically had two different installation
strategies: a kmod from ELrepo or dkms from copr. These have worked
well, but it's still been a bit more cumbersome than one would like,
especially with Secure Boot.

WireGuard has finally been added to CentOS's "kernel-plus" kernels,
which are the normal RHEL kernels, with things added. This means that
WireGuard gets distributed as a built-in to these. It seems to work
well. Instructions are on wireguard.com/install/ and as of writing
suggest the following:


CentOS 8
========
$ sudo yum install yum-utils epel-release
$ sudo yum-config-manager --setopt=centosplus.includepkgs="kernel-plus, kernel-plus-*" --setopt=centosplus.enabled=1 --save
$ sudo sed -e 's/^DEFAULTKERNEL=kernel-core$/DEFAULTKERNEL=kernel-plus-core/' -i /etc/sysconfig/kernel
$ sudo yum install kernel-plus wireguard-tools
$ sudo reboot

CentOS 7
========
$ sudo yum install yum-utils epel-release
$ sudo yum-config-manager --setopt=centosplus.includepkgs=kernel-plus --enablerepo=centosplus --save
$ sudo sed -e 's/^DEFAULTKERNEL=kernel$/DEFAULTKERNEL=kernel-plus/' -i /etc/sysconfig/kernel
$ sudo yum install kernel-plus wireguard-tools
$ sudo reboot

Let me know if there are any issues.

Thanks,
Jason