Synnefo » snf-ganeti

#!/bin/bash

# Copyright (C) 2009 Google Inc.

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful, but

# WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

# General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

# 02110-1301, USA.

# This is an example ganeti hook that writes the instance mac addresses in the

# node's /etc/ether file. It will pic up the first nic connected to the

# TARGET_BRIDGE bridge, and write it down with the syntax "MAC	INSTANCE_NAME".

# The hook will also send a HUP signal the daemon whose PID is in

# DAEMON_PID_FILE, so that it can load the new /etc/ethers file and use it.

# This has been tested in conjunction with dnsmasq's dhcp implementation.

# It will also remove any other occurrences for the same instance in the

# aformentioned file. This hook supports the "instance-add", "instance-modify"

# "instance-remove", and "instance-mirror-replace" ganeti post hook paths. To

# install it add a symlink from those hooks' directories to where this file is

# installed (with a mode which permits execution).

# TARGET_BRIDGE: We'll only add the first nic which gets connected to this

# bridge to /etc/ethers.

TARGET_BRIDGE="br0"

DAEMON_PID_FILE="/var/run/dnsmasq.pid"

# In order to handle concurrent execution of this lock, we use the $LOCKFILE.

# LOCKFILE_CREATE and LOCKFILE_REMOVE are the path names for the lockfile-progs

# programs which we use as helpers.

LOCKFILE="/var/lock/ganeti_ethers.lock"

LOCKFILE_CREATE="/usr/bin/lockfile-create"

LOCKFILE_REMOVE="/usr/bin/lockfile-remove"

hooks_path=$GANETI_HOOKS_PATH

[ -n "$hooks_path" ] || exit 1

instance=$GANETI_INSTANCE_NAME

[ -n "$instance" ] || exit 1

nic_count=$GANETI_INSTANCE_NIC_COUNT

acquire_lockfile() {

  $LOCKFILE_CREATE -l $LOCKFILE || exit 1

  trap "$LOCKFILE_REMOVE -l $LOCKFILE" EXIT

}

update_ethers_from_new() {

  chmod 644 /etc/ethers.new

  mv /etc/ethers.new /etc/ethers

  [ -f "$DAEMON_PID_FILE" ] && kill -HUP $(< $DAEMON_PID_FILE)

}

if [ "$hooks_path" = "instance-add" -o \

     "$hooks_path" = "instance-modify" -o \

     "$hooks_path" = "instance-mirror-replace" ]

then

  for i in $(seq 0 $((nic_count - 1)) ); do

    bridge_var="GANETI_INSTANCE_NIC${i}_BRIDGE"

    bridge=${!bridge_var}

    if [ -n "$bridge" -a "$bridge" = "$TARGET_BRIDGE" ]; then

      mac_var="GANETI_INSTANCE_NIC${i}_MAC"

      mac=${!mac_var}

      acquire_lockfile

      cat /etc/ethers | awk -- "! /^([[:xdigit:]:]*)[[:blank:]]+$instance\>/;

      END {print \"$mac\t$instance\"}" > /etc/ethers.new

      update_ethers_from_new

      break

    fi

  done

fi

if [ "$hooks_path" = "instance-remove" -o \

       \( "$hooks_path" = "instance-modify" -a "$nic_count" -eq 0 \) ]; then

  acquire_lockfile

  cat /etc/ethers | awk -- "! /^([[:xdigit:]:]*)[[:blank:]]+$instance\>/" \

    > /etc/ethers.new

  update_ethers_from_new

fi