These were the steps I needed to perform to run pi-hole in a podman container on Centos8/RHEL8:
First I got it running in podman with the environment I needed (information on additional settings is available from https://hub.docker.com/r/pihole/pihole):
# podman run -d -p 53:53/udp -p 80:80/tcp -e DNS1=1.1.1.1 -e DNS2=8.8.8.8 --name pi-hole -e WEBPASSWORD=admin-password-here docker.io/pihole/pihole