Does not work with pihole DHCP

[ohthehugemanatee]

Though it supports enabling DHCP by variable, some capabilities are missing:

1. sync DHCP reservations (flat file in dnsmasq)
2. sync active DHCP leases (flat file in pihole dir)
3. when keepalived moves the VIP, enable/disable DHCP option accordingly (only one DHCP server should be active at a time) (pihole -a enabledhcp / pihole -a disabledhcp)
4. add dhcp-option=6,${virtual_ip} into a dnsmasq conf file

I'd send a PR but I'm not sure how to have keepalived trigger a script in response to a change in state. At a guess I could add to the status check script to check if the current node is master or backup and respond accordingly.

[ohthehugemanatee]

I threw together a little hard coded version of a keepalive check script that tries to keep dhcpd enabled/disabled appropriately. that takes care of number 3, and the others are very straightforward.

#!/bin/bash
set -e

[ "$(docker inspect -f "{{.State.Health.Status}}" pihole)" = "healthy" ] && HEALTHY=0 || HEALTHY=1

PIHOLE_HOME="/home/ohthehugemanatee/pihole"

# if all of these are true, then return 0, else return 1
if  [ ${HEALTHY} ]; then
  # If we own the primary IP.
  if /usr/sbin/ip a |grep -q 10.10.10.40 ; then
     # Ensure DHCP is enabled.
     if ! [ -f ${PIHOLE_HOME}/dnsmasq.d/02-pihole-dhcp.conf ]; then
       /usr/bin/docker exec -d pihole /usr/local/bin/pihole -a enabledhcp "10.10.10.100" "10.10.10.251" "10.10.10.1" "24" "vert"
     fi
  else
    # Ensure DHCP is disabled.
    if [ -f ${PIHOLE_HOME}/dnsmasq.d/02-pihole-dhcp.conf ]; then
        /usr/bin/docker exec -d pihole /usr/local/bin/pihole -a disabledhcp
    fi
  fi
  exit $HEALTHY
else
  exit $HEALTHY
fi

Got any good suggestions for getting those variables into the script? I guess I need to get them from ansible and do it in the template, but if you have them handy as bash vars I'll use that instead.

[ohthehugemanatee]

I'm now also syncing the whole dnsmasq directory except the dhcp config file, as well as the dhcp leases file. This takes care of numbers 1 and 2.

RSYNC_LEASES=$(rsync -a --info=name -e "ssh $key $host_key_check" $target:$pihole_dir/pihole/dhcp.leases $sync_dir)
  if [ $? -eq 0 ]; then
    if [ -n "$RSYNC_LEASES" ]; then
      sudo cp --preserve=timestamps $sync_dir/dhcp.leases $pihole_dir/pihole
    fi
  fi

  if ! [ -d ${pihole_dir}/dnsmasq.d ]; then
    mkdir -p ${pihole_dir}/dnsmasq.d
  fi

  RSYNC_DNSMASQ=$(rsync -a --info=name -e "ssh $key $host_key_check" --exclude '02-pihole-dhcp.conf' $target:$pihole_dir/dnsmasq.d/* $sync_dir/dnsmasq.d/)
  if [ $? -eq 0 ]; then
    if [ -n "$RSYNC_DNSMASQ" ]; then
      sudo cp --preserve=timestamps $sync_dir/dnsmasq.d/* $pihole_dir/dnsmasq.d
    fi
  fi

The whole setup is working for me... now I'll work on getting it into ansible/templates.