add a script for lxc net config

lxc_network_hostonlyplusnat.sh

@@ -0,0 +1,94 @@
+#!/bin/bash
+
+
+# Print some usage info
+function usage {
+  echo "Usage: $0 [OPTION] [host_ip]"
+  echo "Set up networking for LXC"
+  echo ""
+  echo "  -n, --dry-run            Just print the commands that would execute."
+  echo "  -h, --help               Print this usage message."
+  echo ""
+  exit
+}
+
+# Allow passing the ip address on the command line.
+function process_option {
+  case "$1" in
+    -h|--help) usage;;
+    -n|--dry-run) dry_run=1;;
+    *) host_ip="$1"
+  esac
+}
+
+# Set up some defaults
+host_ip=
+dry_run=0
+bridge=br0
+DRIER=
+
+# Process the args
+for arg in "$@"; do
+  process_option $arg
+done
+
+if [ $dry_run ]; then
+  DRIER=echo
+fi
+
+if [ "$UID" -ne "0" ]; then
+  echo "This script must be run with root privileges."
+  exit 1
+fi
+
+# Check for bridge-utils.
+BRCTL=`which brctl`
+if [ ! -x "$BRCTL" ]; then
+  echo "This script requires you to install bridge-utils."
+  echo "Try: sudo apt-get install bridge-utils."
+  exit 1
+fi
+
+# Scare off the nubs.
+echo "====================================================="
+echo
+echo "WARNING"
+echo
+echo "This script will modify your current network setup,"
+echo "this can be a scary thing and it is recommended that"
+echo "you have something equivalent to physical access to"
+echo "this machine before continuing in case your network"
+echo "gets all funky."
+echo
+echo "If you don't want to continue, hit CTRL-C now."
+
+if [ -z "$host_ip" ];
+then
+  echo "Otherwise, please type in your host's ip address and"
+  echo "hit enter."
+  echo
+  echo "====================================================="
+  read host_ip
+else
+  echo "Otherwise hit enter."
+  echo
+  echo "====================================================="
+  read accept
+fi
+
+
+# Add a bridge interface, this will choke if there is already
+# a bridge named $bridge
+$DRIER $BRCTL addbr $bridge
+$DRIER ip addr add 192.168.1.1/24 dev $bridge
+if [ $dry_run ]; then
+  echo "echo 1 > /proc/sys/net/ipv4/ip_forward"
+else
+  echo 1 > /proc/sys/net/ipv4/ip_forward
+fi
+$DRIER ifconfig $bridge up
+
+# Set up the NAT for the instances
+$DRIER iptables -t nat -A POSTROUTING -s 192.168.1.0/24 -j SNAT --to-source $host_ip
+$DRIER iptables -I FORWARD -s 192.168.1.0/24 -j ACCEPT
+