Description of problem:
Discovery ramdisk detects _possible_ amount of RAM, not actual one. It was fixed in Git master by commit https://github.com/rdo-management/instack-undercloud/commit/9327553ecbbb7cc20bf32dd940bb32d02edb5b94 and in DIB ramdisk by patch https://review.openstack.org/#/c/156173/.
on bare metal machines with RAM != maximum RAM
Steps to Reproduce:
1. go through discovery on such a machine
2. Node.extra[memory_mb] in Ironic will be updated with wrong value
Fixed in stable/juno branch of instack-undercloud as commit https://github.com/rdo-management/instack-undercloud/commit/02853ff37851736d0aecdda3d30afe94db35b782
The machine has 48GB of ram.
After the discovery, running "ironic node-show <id>":
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.