When installing RHCOS on Oracle Cloud with an iSCSI boot drive, the DNS configuration is not retrieved on first boot when ip=dhcp, ip=ens3:dhcp or ip=ibft is passed as kernel arguments.

DNS configuration is retrieved when no ip= or ip=auto is passed to the kernel arguments.

x-systemd.device-timeout=0 doesn't seem as no effects.

    Red Hat Enterprise Linux CoreOS 415.92.202401082022-0

always

    

# 1. Create a minimal iso
$ coreos-installer iso extract minimal-iso rhcos-415.92.202401082022-0-live.x86_64.iso rhcos-415.92.202401082022-0-min-live.x86_64.iso

# 2. Extract boot artifacts
$ coreos-installer iso extract pxe rhcos-415.92.202401082022-0-live.x86_64.iso rhcos-415.92.202401082022-0-min-live.x86_64.iso 

# 3. Upload the rootfs in a bucket in Oracle Cloud, generate a pre-authenticated URL
$ coreos-installer iso kargs modify -a coreos.live.rootfs_url=https://objectstorage.us-sanjose-1.oraclecloud.com/p/XXX/rhcos-415.92.202401082022-0-live.x86_64-rootfs.img -a console=ttyS0  rhcos-415.92.202401082022-0-min-live.x86_64.iso

# 4. Embed an ignition to set core user password
$ cat ignition.json
{"ignition":{"version":"3.3.0"},"passwd":{"users":[{"name":"core","passwordHash":"xxx"}]}}
$ coreos-installer iso ignition embed -i ignition.json rhcos-415.92.202401082022-0-min-live.x86_64.iso

5. Upload the minimal ISO into a bucket in Oracle Cloud
6. Create a custom image out of the minimal ISO (import the ISO as QCOW)
7. Edit the custom image capabilities, leave UEFI firmware and iSCSI boot volume selected
8. Create an VM instance from the custom image, and open a console using core user and its password defined above

# 9. configure iSCSI
$ modprobe iscsi_ibft
$ iscsistart -f
$ iscsistart -b

# 10. install core os on the iSCSI volume (use the same ignition as above to set core user password)
$ coreos-installer install -i ign --append-karg rd.iscsi.firmware=1 --append-karg console=ttyS0 --append-karg ip=dhcp /dev/sda 
$ systemctl reboot

# 11. log on the installed system, and check DNS configuration
$ nmcli

    DNS configuration is not set on first boot when ip=dhcp, ip=ens3:dhcp, ip=ibft

    DNS configuration is set properly on first boot

    sos report (after `nmcli device reapply ens3` to get DNS): https://drive.google.com/file/d/1frtkpgfsdZXTjgbhBYy_Qa0w0b8PNTeX/view?usp=drive_link
    slack thread: https://redhat-internal.slack.com/archives/C05UQ2Y7HKR/p1704827794373749