Use following command to create config for GPDB cluster:

git clone https://github.com/lij55/bootgpdb.git

cd bootgpdb

source /path/to/gpdb/greenplum_path.sh

./prepare.sh -n num_of_segment_per_host -s num_of_seg_hosts

source env.sh

gpinitsystem -a -c gpinitsystem_config