The steps provided below worked for a similar case for DL20 Gen9 server. I think the key item is using the HPE Dynamic Smart Array B140i SATA RAID Controller Driver for Red Hat Enterprise Linux driver provided in step 2.
1) Download CentOS Image and write it on a USB using
dd if=/path/to/CentOS.iso of=/dev/sdX status=progress);
2) Download hpdsa-1.2.10-123.rhel7u3.x86_64.dd.gz file from the following webpage:
dd to write the appropriate driver (u0 or u1) on a separate USB drive (ex.
dd if=/path/to/HpDsaExtractedDriver.dd of=/dev/sdY status=progress);
4) Insert the CentOS USB in the server, boot from it but at the install menu, press e in case of an UEFI system and on the "linuxefi" line append the following
5) Press Ctrl+x or the keys needed to continue the installation;
6) Insert the usb drive with the driver;
7) Press r to refresh the drive list and choose the appropriate drive;
8) After it unpacks, continue with the installation as usual.
This support communication also has similar instructions for REHL 7.x that should also work for Centos 7
Red Hat Enterprise Linux 7.x - B140i Raid Controller Driver Update disk (dd) Creation