I’m running into inconsistently successful commissions/deploys against rack controllers that host a large number of subnets (they have a lot of interfaces). The rack controller itself is practically IDLE, however PXEboots fail occasionally with netconn_connect error -10 and during boot, Hitting enter will usually continue the PXEboot failure and succeed. However during boot ocasionally connecting to the MAAS metadata endpoint seems to hang and eventually fail out a lot more than expected. During these the rack controller is only service requests for a single subnet. The machines being provisioned are using HA DHCP helper to the HA rack controller(s) for that subnet.
maas 2.9.2 (snap, stable), the regions are 3 region controllers in a HA config as per maas documentaiton.