ctdb/config/events.d/11.natgw

   1 #!/bin/sh
   2 # Script to set up one of the nodes as a NAT gateway for all other nodes.
   3 # This is used to ensure that all nodes in the cluster can still originate
   4 # traffic to the external network even if there are no public addresses
   5 # available.
   6 #
   7
   8 . $CTDB_BASE/functions
   9 loadconfig ctdb
  10
  11 [ -z "$NATGW_PUBLIC_IFACE" ] && exit 0
  12
  13 cmd="$1"
  14 shift
  15 PATH=/usr/bin:/bin:/usr/sbin:/sbin:$PATH
  16
  17
  18 delete_all() {
  19         remove_ip $NATGW_PUBLIC_IP $NATGW_PUBLIC_IFACE
  20         remove_ip $NATGW_PUBLIC_IP_HOST lo
  21
  22         ip route del 0.0.0.0/0 metric 10 >/dev/null 2>/dev/null
  23
  24         # Delete the masquerading setup from a previous iteration where we
  25         # were the NAT-GW
  26         iptables -D POSTROUTING -t nat -s $NATGW_PRIVATE_NETWORK -d ! $NATGW_PRIVATE_NETWORK -j MASQUERADE >/dev/null 2>/dev/null
  27
  28 }
  29
  30 case $cmd in
  31      recovered)
  32         MYPNN=`ctdb pnn | cut -d: -f2`
  33         NATGWMASTER=`ctdb natgwlist | head -1`
  34         NATGWIP=`ctdb natgwlist | tail --lines=+2 | head -1 | cut -d: -f3`
  35
  36         NATGW_PUBLIC_IP_HOST=`echo $NATGW_PUBLIC_IP | sed -e "s/\/.*/\/32/"`
  37
  38         delete_all
  39
  40         if [ "$MYPNN" == "$NATGWMASTER" ]; then
  41                 # This is the first node, set it up as the NAT GW
  42                 echo 1 >/proc/sys/net/ipv4/ip_forward
  43                 iptables -A POSTROUTING -t nat -s $NATGW_PRIVATE_NETWORK -d ! $NATGW_PRIVATE_NETWORK -j MASQUERADE
  44                 ip addr add $NATGW_PUBLIC_IP dev $NATGW_PUBLIC_IFACE
  45                 ip route add 0.0.0.0/0 via $NATGW_DEFAULT_GATEWAY >/dev/null 2>/dev/null
  46         else
  47                 # This is not the NAT-GW
  48                 # Assign the public ip to the private interface and make
  49                 # sure we dont respond to ARPs.
  50                 # We do this so that the ip address will exist on a
  51                 # non-loopback interface so that samba may send it along in the
  52                 # KDC requests.
  53                 ip addr add $NATGW_PUBLIC_IP_HOST dev lo
  54                 ip route add 0.0.0.0/0 via $NATGWIP metric 10
  55         fi
  56
  57         # flush our route cache
  58         echo 1 > /proc/sys/net/ipv4/route/flush
  59         ;;
  60
  61      shutdown)
  62         delete_all
  63         ;;
  64
  65 esac
  66
  67 exit 0