Commit 93db3d8f authored by Guido Trotter's avatar Guido Trotter

Add an example "ethers" hook

This hook can be used to update /etc/ethers with instance's mac
addresses. A dhcp server on the nodes can then serve to the instances
their correct address. (This has been tested with dnsmasq's dhcp
implementation)
Signed-off-by: default avatarGuido Trotter <ultrotter@google.com>
parent c70481ab
#!/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"
LOCKFILE="/var/lock/ganeti_ethers.lock"
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() {
if ! ( set -o noclobber; echo "$$" > $LOCKFILE) 2> /dev/null; then
logger -s "Cannot acquire lockfile for ethers update"
exit 1
fi
trap "rm -f $LOCKFILE" EXIT
}
update_ethers_from_new() {
chmod 644 /etc/ethers.new
mv /etc/ethers.new /etc/ethers
[ -f "$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
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