Comment 16 for bug 1818239

I've marked this as incomplete for nova since I'm not aware of any changes being asked to make here. The build failure weigher was added because of bug 1742102 and in response to operator feedback from the Boston summit to auto-disable computes if they experienced a build failure. So the auto-disable thing went into I think Pike, and then bug 1742102 talked about how that was too heavy weight because there were easy ways to auto-disable a lot of computes in a deployment (e.g. volume over-quota from multiple concurrent boot from volume server create requests). So Dan added the weigher stuff which can be configured to weigh hosts with build failures lower so they don't become a black hole, and once the host has a successful build the stats tracking for that compute node is reset.

Anyway, it's up to charms if it wants to disable it by default, but note it was added for a reason and defaults to being "on" for a reason as well (per operator feedback).