We are performing adoption from RHOSP17.1 to RHOSO18. We have observed that.. in RHOSO, the canonical hostname of compute nodes is derived from the ctlplane network DnsDomain. So, we have set DnsDomain of "ctlplane" network to a value "redhat.local" that matches to old tripleo configured CloudDomain. This way we avoid hostname mismatches after adoption and the problems that come with it(https://issues.redhat.com/browse/OSPRH-26019).

So now, according to RHOSO these hostnames must resolve to ctlplane network on compute nodes. But, old tripleo already configured this hostname to be resolved on internal_api network. After the adoption, compute node hostnames are still being resolved to internal_api Ip and not ctlplane.

Root cause:
/etc/hosts entries are not cleared on computes during adoption, which had an entry resolving compute hostname to internal_api.

Actual results:
Compute hostname being resolved to internal_api after adoption.

Expected results:
Compute hostname should be resolved to ctlplane after adoption.