Kickstart
Kickstart is a tool to automate the installation of RHEL systems. It allows the system to be booted and configured from the initial command line with a simple command like:
linux ks=http://<ip-address>/kickstart/ks.cfg inst.repo=http://<ip-address>/rhel9
Cloud-init
Cloud-init is a standard tool for automating cloud-based Linux deployments. It runs on the first boot on a cloud instance. It reads from a YAML file to define how the system should start, and can include things like SSH keys, add packages, or run custom scripts.