mrcharles
d6988bb35f
Root cause of intermittent DNS up/down alerts: Pi-hole's default
rate-limit (1000 queries/60s per client) was throttling Uptime Kuma
on the Cloudron VPS (tsys-cloudron, 100.107.35.78). Uptime Kuma sends
high-volume DNS queries to monitor dozens of hosts; when it exceeded
the limit, Pi-hole responded REFUSED, which Uptime Kuma detected as
DNS being down. This happened every 1-2 minutes.
Evidence: 40 rate-limiting events against 100.107.35.78 in recent
netinfra-01 Pi-hole logs. Also 10.53.0.1 (Docker bridge gateway) hit
4852 queries in a single 60s window.
Fix: Set dns.rateLimit.count=0 and dns.rateLimit.interval=0 on both
nodes (private tailnet, no DNS amplification risk). Also persisted in
docker-compose.yml via FTLCONF env vars.
Combined with prior IPv6 fix (4f82520), this resolves all known causes
of DNS flapping.
[#376]
56 lines
1.7 KiB
YAML
56 lines
1.7 KiB
YAML
services:
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pihole:
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container_name: pihole
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# Root cause of the 2026-08 gravity.db corruption: default /dev/shm (64M)
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# was too small for FTL's shared-memory metrics. 1024M has been stable.
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shm_size: '1024M'
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image: pihole/pihole:latest
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hostname: pihole
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entrypoint: ["/usr/local/bin/gravity-validate.sh"]
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ports:
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- "53:53/tcp"
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- "53:53/udp"
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- "10002:80/tcp"
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- "10003:443/tcp"
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environment:
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TZ: 'America/Chicago'
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FTLCONF_webserver_api_password: '${PIHOLE_WEB_PASSWORD}'
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FTLCONF_dns_listeningMode: 'all'
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# Rate-limiting disabled (count=0). Uptime Kuma on Cloudron VPS sends
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# high-volume DNS queries for monitoring; default 1000/60s limit was
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# causing intermittent REFUSED responses → Uptime Kuma flapping.
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FTLCONF_dns_rateLimit_count: '0'
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FTLCONF_dns_rateLimit_interval: '0'
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FTLCONF_dns_upstreams: '["8.8.8.8"]'
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volumes:
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- './etc-pihole:/etc/pihole'
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- './etc-dnsmasq.d:/etc/dnsmasq.d'
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- './gravity-validate.sh:/usr/local/bin/gravity-validate.sh:ro'
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cap_add:
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- SYS_NICE
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restart: always
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healthcheck:
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test: ["CMD-SHELL", "dig +short +norecurse @127.0.0.1 pi.hole >/dev/null 2>&1 && test -s /etc/pihole/gravity.db || exit 1"]
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interval: 30s
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timeout: 10s
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retries: 3
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start_period: 60s
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labels:
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autoheal: "true"
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networks:
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- default
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- dnsnet
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autoheal:
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container_name: autoheal
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image: willfarrell/autoheal:latest
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environment:
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AUTOHEAL_CONTAINER_LABEL: autoheal
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AUTOHEAL_INTERVAL: 30
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AUTOHEAL_START_PERIOD: 60
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volumes:
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- '/var/run/docker.sock:/var/run/docker.sock:ro'
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restart: always
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networks:
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dnsnet:
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external: true
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