an inventory file is literally a static list of pets in its simplest form, and with some simple convention you could have a directory per-host with any playbooks required. plus you have docs, community modules, etc.
Turns out that, like Puppet, Ansible seems to have been congealed rather than designed, and it's a mess of inconsistent spaghetti code.
All the other config management systems I've tried, from Salt to Chef have exactly the same problem.
I'd be thrilled to find a config management system that actually was simple and elegant.
1. When a system comes in, it is scanned and entered into the asset management database, which then triggers a process to enter the scanned MAC address into the DHCP, by generating a new DHCP configuration package.
2. the previous version of the DHCP configuration package is upgraded with the new DHCP configuration package.
3. the system is hooked up to the network and powered on.
4. the firmware is permanently reconfigured to boot in this order: 1. HD0 2. HD1 3. network.
5. since HD0 and HD1 are not bootable, the system boots from the network, whereby the infrastructure automatically provisions it with the standard runtime platform, which consists solely of packages in OS-native format, including configuration packages which configure things which all servers have in common.
6. as part of the automatic installation, the server is automatically installed with additional configuration packages based on which profile it is in, turning it into a specific application server.
7. the server comes up after automatic installation, and reports back to the infrastructure that it is ready to serve.
NEVER by hand!