https://docs.k3s.io/installation/airgap#manually-deploy-images-method
https://github.com/k3s-io/k3s/
# download these
mkdir /opt/k3s && cd /opt/k3s
curl -#LO https://github.com/k3s-io/k3s/releases/download/v1.25.12%2Bk3s1/k3s
curl -#L https://get.k3s.io -o install.sh
curl -#LO https://github.com/k3s-io/k3s/releases/download/v1.25.12%2Bk3s1/k3s-airgap-images-amd64.tar
curl -#LO https://github.com/k3s-io/k3s-selinux/releases/download/v1.4.stable.1/k3s-selinux-1.4-1.el9.noarch.rpm
chmod 755 k3s install.sh
this step should be self explanatory.
# compress
cd /opt/k3s
tar -vzcf /opt/k3s_airgapped.tgz $(ls)
# decompress
mkdir /opt/k3s
tar -vzxf /opt/k3s_airgapped.tgz -C /opt/k3s
run as root
cd /opt/k3s
mkdir -p /var/lib/rancher/k3s/agent/images/
mv k3s /usr/local/bin/
mv k3s-airgap-images-amd64.tar /var/lib/rancher/k3s/agent/images/
yum install -y container-selinux k3s-selinux-1.4-1.el9.noarch.rpm
INSTALL_K3S_SKIP_DOWNLOAD=true ./install.sh