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
Then I created a systemd service for it:
# cat <<'EOF' > /etc/systemd/system/pi-hole-container.service
[Unit]
Description=Pi-hole container
[Service]
Restart=always
ExecStart=/usr/bin/podman start -a pi-hole
ExecStop=/usr/bin/podman stop -t 2 pi-hole
[Install]
WantedBy=local.target
EOF
And finally killed my running container and verified that it got started from the systemd service:
# podman kill pi-hole
# systemctl enable pi-hole-container.service
# systemctl start pi-hole-container.service