This is a simple playbook for setting up a compiling environment for OpenWrt.
You should provide a VM or server where you have root privileges.
This playbook aims to be compatible with current Debian stable.
It will install all required packages, clone openwrt repository and execute the initial install scripts.
Specify the host ip on hosts.ini, then execute ansible-playbook -i hosts.ini openwrt-compiler.yml -u root.
Next you can login as user forger, go to /home/forger/openwrt/ and execute make menuconfig to launch the config interface. Choose your desired settings and execute make to start compilation.
These steps are based on OpenWrt Image Building Guide.