Installed DRDB Utilities but there is no /dev/drbd0 device even after running the command
drbdadm create-md r0. Is there a command to create /dev/drbd0 device?
You have created the meta-data for the device, but you then must bring the DRBD resource/device "up". You can do this with either the command
drbdadm up r0, or via the systemd unit file.
Please note that bringing the resource up will make the /dev/drbd0 device appear, but it will still be unusable until you promote it to primary. This is usually done via
drbdadm primary r0, but the first time you must decide upon a sync source with
drbdadm primary r0 --force.