From d9614163ed327fc17d27ac623dfd639ce00a43ce Mon Sep 17 00:00:00 2001 From: Micah Anderson Date: Wed, 19 Jun 2013 13:41:23 -0400 Subject: disable dhclient from modifying the /etc/resolv.conf file on openstack/amazon instances The dhclient in these environments is quite aggressive and overwrites the nameservers we've deliberately chosen to use with google's nameservers. This commit attempts to fix that. The dhclient methodology for altering these things is particularly unpleasant. We effectively redefine the functions that mess with this file to be noops in the /etc/dhcp/dhclient-enter-hooks.d directory and then we are forced to restart dhclient by shipping a script that tries to determine the correct PID and arguments that it was running as before killing and restarting it with the same arguments. See debian bugs #681698, #712796 for further discussion about how to make this less difficult Change-Id: I51cf40cf98eaddcefd8180e157b6e3ca824173f0 --- puppet/modules/site_config/manifests/default.pp | 6 ++++- puppet/modules/site_config/manifests/dhclient.pp | 30 ++++++++++++++++++++++ .../site_config/templates/reload_dhclient.erb | 13 ++++++++++ 3 files changed, 48 insertions(+), 1 deletion(-) create mode 100644 puppet/modules/site_config/manifests/dhclient.pp create mode 100644 puppet/modules/site_config/templates/reload_dhclient.erb diff --git a/puppet/modules/site_config/manifests/default.pp b/puppet/modules/site_config/manifests/default.pp index cfb46130..5518ea56 100644 --- a/puppet/modules/site_config/manifests/default.pp +++ b/puppet/modules/site_config/manifests/default.pp @@ -12,10 +12,14 @@ class site_config::default { # configure apt include site_apt - # configure ssh and include ssh-keys include site_config::sshd + # fix dhclient from changing resolver information + if $::ec2_instance_id { + include site_config::dhclient + } + # configure /etc/resolv.conf include site_config::resolvconf diff --git a/puppet/modules/site_config/manifests/dhclient.pp b/puppet/modules/site_config/manifests/dhclient.pp new file mode 100644 index 00000000..7ac0caf3 --- /dev/null +++ b/puppet/modules/site_config/manifests/dhclient.pp @@ -0,0 +1,30 @@ +class site_config::dhclient { + + # Unfortunately, there does not seem to be a way to reload the dhclient.conf + # config file, or a convenient way to disable the modifications to + # /etc/resolv.conf. So the following makes the functions involved noops and + # ships a script to kill and restart dhclient. See the debian bugs: + # #681698, #712796 + + include site_config::params + + file { '/usr/local/sbin/reload_dhclient': + owner => 0, + group => 0, + mode => '0755', + content => template('site_config/reload_dhclient.erb'); + } + + exec { 'reload_dhclient': + refreshonly => true, + command => '/usr/local/sbin/reload_dhclient'; + } + + file { '/etc/dhcp/dhclient-enter-hooks.d/disable_resolvconf': + content => 'make_resolv_conf() { : ; } ; set_hostname() { : ; }', + mode => '0644', + owner => 'root', + group => 'root', + notify => Exec['reload_dhclient']; + } +} diff --git a/puppet/modules/site_config/templates/reload_dhclient.erb b/puppet/modules/site_config/templates/reload_dhclient.erb new file mode 100644 index 00000000..882c985a --- /dev/null +++ b/puppet/modules/site_config/templates/reload_dhclient.erb @@ -0,0 +1,13 @@ +#!/bin/sh + +# Get the PID +PIDFILE='/var/run/dhclient.<%= scope.lookupvar('site_config::params::interface') %>.pid + +# Capture how dhclient is currently running so we can relaunch it +dhclient=`/bin/ps --no-headers --pid $(cat $PIDFILE) -f | /usr/bin/awk '{for(i=8;i<=NF;++i) printf("%s ", $i) }'` + +# Kill the current dhclient +/usr/bin/pkill -F $PIDFILE + +# Restart dhclient with the arguments it had previously +$dhclient -- cgit v1.2.3