The ironic TFTP server should be accessed via the internal API network.
For ironic inspector, dnsmasq.conf advertises this correctly:
dhcp-option=option:tftp-server,'api_interface_address'
dhcp-option=option:server-ip-address,'api_interface_address'
However, ironic conductor does not set the [pxe] tftp_server variable.
This means the TFTP server advertised gets the default value of $my_ip,
which is set by
https://docs.openstack.org/oslo.utils/latest/reference/netutils.html#oslo_utils.netutils.get_my_ipv4,
typically the source IP for the default route.
This change sets [pxe] tftp_server to 'api_interface_address'.
Change-Id: Ic3e688b3f2b92ad9515322f49cd5f4f29d763e49
Closes-Bug: #1808347
4d64646699