What is better than a Pi-hole blocking trackers, advertisements, and other malicious domains on your network? That's right, two Pi-hole blocking all that junk on your network!

• Seriously. Why two Pi-hole?

But if you have redundant Pi-hole in your network you'll want a simple way to keep the list configurations and local DNS settings identical between the two. That's where Gravity Sync comes in. Setup should only take a few minutes.

• pihole-FTL sql replaced with pihole-FTL sqlite3 -ni
• pihole restartdns replaced with pihole reloaddns / pihole reloadlists
• Custom DNS records path updated to hosts/custom.list
• CNAME and static DHCP sync now uses the FTL config API (pihole-FTL --config) instead of dnsmasq config files, which were removed in v6
• Full TOML config sync — 30+ configurable keys (DNS settings, blocking, cache, DHCP, resolver, database)
• Automatic Pi-hole v6 detection — falls back to legacy dnsmasq file sync if v6 is not detected

Gravity Sync replicates the core of Pi-hole's ad/telemetry blocking settings, which includes:

• Adlist settings with status and comments.
• Domain/RegEx whitelists and blacklist along with status and comments.
• Clients and group assignments, along with status and descriptions.

Gravity Sync also replicates local network DNS/DHCP settings, which includes:

• Local DNS Records.
• Local CNAME Records (via FTL config API on v6).
• Static DHCP Assignments (via FTL config API on v6).
• All configurable pihole.toml keys (see PH_V6_TOML_SYNC_KEYS in ENV.md).

Gravity Sync will not:

• Modify or sync the individual Pi-hole's upstream DNS resolvers.
• Merge query logs, statistics, long-term data, caches, or other resolution information.
• Sync individual Pi-hole DHCP scoping information or leases.

• Pi-hole v6.x on both primary and secondary instances
• SSH key-based authentication between the two hosts
• rsync installed on both hosts
• inotify-tools (optional, for event-based auto-sync)

1. Copy gravity-sync to /usr/local/bin/gravity-sync on the primary Pi-hole
2. Create config: sudo mkdir -p /etc/gravity-sync && sudo nano /etc/gravity-sync/gravity-sync.conf
3. Set REMOTE_HOST and REMOTE_USER in the config
4. Set GS_SSH_PKIF to your SSH private key path
5. Test: sudo gravity-sync compare
6. Sync: sudo gravity-sync push

Reacts instantly when Pi-hole config changes, zero CPU overhead while idle.

sudo apt install inotify-tools -y
sudo cp templates/gravity-sync-watch.sh /usr/local/bin/
sudo chmod +x /usr/local/bin/gravity-sync-watch.sh
sudo cp templates/gravity-sync-watch.service /etc/systemd/system/
sudo systemctl enable --now gravity-sync-watch.service

sudo cp templates/gravity-sync.service /etc/systemd/system/
sudo cp templates/gravity-sync.timer /etc/systemd/system/
sudo systemctl enable --now gravity-sync.timer

docker build -t gravity-sync .
docker run -v /path/to/gravity-sync.conf:/etc/gravity-sync/gravity-sync.conf \
           -v /path/to/ssh-key:/root/.ssh/id_ed25519:ro \
           gravity-sync push

A standalone Python tool that merges query logs from both Pi-hole instances into a single filterable web view. No external dependencies required.

cp viewer-config.example.json viewer-config.json
# Edit viewer-config.json with your Pi-hole URLs and passwords
python3 pihole-query-viewer.py
# Open http://localhost:8088

Filters: domain search, allowed/blocked status, primary/secondary source, DNS type, upstream server.

Gravity Sync is not developed by or affiliated with the Pi-hole project. This is an unofficial, community effort, that seeks to implement replication (which is currently not a part of the core Pi-hole product) in a way that provides stability and value to Pi-hole users. The code has been tested across multiple user environments but there always is an element of risk involved with running any arbitrary software you find on the Internet.

Pi-hole is and the Pi-hole logo are registered trademarks of Pi-hole LLC.

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• Frequently Asked Questions
• Changelog