Installation - Grafana

sudo apt-get update && sudo apt-get upgrade -y && sudo apt-get autoremove -y && sudo apt-get autoclean -y
sudo apt-get install -y adduser libfontconfig1
wget https://dl.grafana.com/oss/release/grafana_8.3.1_amd64.deb
sudo dpkg -i grafana_8.3.1_amd64.deb
sudo systemctl daemon-reload
sudo systemctl start grafana-server
sudo systemctl status grafana-server

Installation - Pihole Exporter

wget https://github.com/eko/pihole-exporter/releases/latest/download/pihole_exporter-linux-amd64
sudo mkdir /etc/pihole_exporter
 
sudo mv pihole_exporter-linux-amd64 /etc/pihole_exporter
sudo chown pihole_exporter:pihole_exporter /etc/pihole_exporter/pihole_exporter-linux-amd64
sudo chmod +x /etc/pihole_exporter/pihole_exporter-linux-amd64
sudo systemctl daemon-reload
sudo systemctl start pihole_exporter
sudo systemctl status pihole_exporter

Configuration & Service Creation

sudo useradd -r pihole_exporter
sudo nano /etc/systemd/system/pihole_exporter.service

                    [Unit]
                    Description=pihole_exporter

                    [Service]
                    ExecStart=/etc/pihole_exporter/pihole_exporter-linux-amd64
                    WorkingDirectory=/etc/pihole_exporter
                    Restart=always
                    User=pihole_exporter

                    [Install]
                    WantedBy=multi-user.target
                    
Enable the systemd service to run on startup, then start the service and check its status:
sudo systemctl enable pihole_exporter
sudo systemctl start pihole_exporter
sudo systemctl status pihole_exporter

Now test that it is working!
curl 127.0.0.1:9617
telegraf --config /etc/telegraf/telegraf.conf --config-directory /etc/telegraf/telegraf.d/ --input-filter snmp -test

Documentation

Download Grafana
Pihole Dashboard for Grafana
Pihole Exporter Download
https://community.grafana.com