I think I've found an issue with how Foreman deals with DNS entries for Openstack VMs.

The DNS records (A record and PTR record) for VMs are created correctly, with the floating IP being used for both records. However, when a VM is deleted, Foreman sometimes tries to delete a PTR record with the fixed IP, which obviously doesn't exist. This leads to old PTR records not being cleaned up and eventually DNS conflicts when new VMs are created.

I've grabbed the relevant entries from the Foreman proxy log. Here is the VM being created:

DEBUG – : running /usr/bin/nsupdate -k /var/named/chroot/etc/Kforeman.+157+35782.private
DEBUG – : nsupdate: executed - server 172.25.96.7
DEBUG – : nsupdate: executed - update add 7.120.25.172.in-addr.arpa. 86400 IN PTR newtest.office.example.com
DEBUG – : running /usr/bin/nsupdate -k /var/named/chroot/etc/Kforeman.+157+35782.private
DEBUG – : nsupdate: executed - server 172.25.96.7
DEBUG – : nsupdate: executed - update add newtest.office.example.com. 86400 A 172.25.120.7

Note it's using 172.25.120.7, which is the floating IP for the VM.

Now the log from when the VM is deleted:

DEBUG – : running /usr/bin/nsupdate -k /var/named/chroot/etc/Kforeman.+157+35782.private
DEBUG – : nsupdate: executed - server 172.25.96.7
DEBUG – : nsupdate: executed - update delete newtest.office.example.com A
DEBUG – : running /usr/bin/nsupdate -k /var/named/chroot/etc/Kforeman.+157+35782.private
DEBUG – : nsupdate: executed - server 172.25.96.7
DEBUG – : nsupdate: executed - update delete 4.96.25.172.in-addr.arpa PTR

Here it tries to delete a PTR record for 127.25.96.4, which is the fixed IP address of the VM. As that record was never created the operation fails, and the correct PTR record isn't cleaned up.

This is with Foreman 1.3.0.