Setup with one PiHole is good enough for most of the users, however my whole house runs on PiHole (including the DHCP server), so I need something that will work, even if the Pi goes down.

First I’ve installed two PiHole servers. In my case one is running on old Pi1B, another in LXC in Proxmox. That means they don’t even need to be running the same architecture.

If you want PiHole to run as DHCP server

I want them to serve as DHCP servers, so I enabled the DHCP servers in two interfaces (pihole1 and pihole2), but set DHCP range to something else.

In my case I set it to:

  • pihole1: 192.168.178.100 - 192.168.178.149
  • pihole2: 192.168.178.150 - 192.168.178.200

This way each client will get the IP from any of those DHCP servers and there will be no conflicts in IPs assigned.

I also have some static IPs assigned from the range 192.168.178.2 - 192.168.178.99, but I don’t have to worry about them as they will be synchronized.

There is one more thing to do, I had to login to each of the piholes and execute:

sudo nano /etc/dnsmasq.d/99-second-DNS.conf

Add there this line (it will tell DHCP server to send those 2 DNS servers):

dhcp-option=option:dns-server,192.168.178.253,192.168.178.254

Then close nano and do:

sudo pihole restartdns

Synchronization

There are multiple options. One of them is GravitySync which works fine, but seems to be more CPU and storage intensive than what I want my Raspberry Pi 1 to go through. So I use OrbitalSync instead, it’s easy to setup and requires one docker-compose file:

version: '3'
services:
  orbital-sync:
    image: mattwebbio/orbital-sync:1
    environment:
      PRIMARY_HOST_BASE_URL: 'http://192.168.178.253'
      PRIMARY_HOST_PASSWORD: 'password1'
      SECONDARY_HOST_1_BASE_URL: 'http://192.168.178.254'
      SECONDARY_HOST_1_PASSWORD: 'password2'
      INTERVAL_MINUTES: 30

After deployed, the container will sync settings (including DHCP leases, whitelists, etc.) every 30 minutes.