IPMI network configuration clarification

[timbargo]

What does chi-in-a-box expect for an IPMI configuration?
Does the controller node provide DHCP for IPMI addresses?
Should you set IPMI addresses to match ironic_provisioning subnet in site-config/defaults.yml? (The answer here is no)

I originally asked this question in Slack. Opening a Github issue at Mark's request and pasting his original Slack response to the question for the issue record.

it doesn’t provide DHCP by default for the IPMI addresses. We’ve been habitually setting them to static IPs, but you could run a dhcp server instead
all we assume is routed access to whatever addresses they have, it actually shouldn’t be the ironic_provisioning subnet, which is instead used to boot the nodes onto while loading an image
simplest would likely be to put the IPMI interfaces on a separate switch/vlan/network, and give them a dedicated subnet, and then put some address in that subnet on the controller node
the goal being that we want those interfaces to work, even if the entire set of openstack services is down. Just a safeguard against circular dependencies

[msherman64]

This has been somewhat addressed, in that installation will now succeed, even if a value is not provided.
However, better docs are still needed.

ironic_dnsmasq_dhcp_range is only used for ironic_inspector, not normal usage, and we set a default in 40ec7b3

The ironic provisioning network now defaults to 10.51.0.0/24, but can be customized. New defaults were set in ef4d2fc#diff-6fee6f934c49cf2e47394ce307eee4aba6d894e9b7f5bdc1fbf5eae345c59f9d