[Puppet Users] Creating configuration for dhcpd

Hi,
I am trying to set up puppet for creating configuration files for
automatic installation. I have a node which runs both puppet master
and dhcp server. On this node I wanna create configuration file for
dhcpd which will contain static ip address definition for each host.
Like this :

...
host node1 { hardware ethernet 08:00:27:ed:8f:ea; fixed-address
192.168.2.1; }
host node2 { hardware ethernet 08:00:27:df:b4:0c; fixed-address
192.168.2.2; }
host node3 { hardware ethernet 78:e7:d1:24:5c:10; fixed-address
192.168.2.3; }
...

My configuration:

/etc/puppet/manifests/site.pp:
import "nodes/puppet.pp"

/etc/puppet/manifests/nodes/puppet.pp:
import "/etc/puppet/manifests/roles/puppetserver.pp"

node 'puppet' inherits puppetserver {
} #node puppet

/etc/puppet/manifests/roles/puppetserver.pp:
import "/etc/puppet/manifests/roles/basenode.pp"
node 'puppetserver' inherits basenode {
preseed {
"node1":
mac1 => "44-1e-a1-39-05-a0",
mac2 => "44:1e:a1:39:05:a0",
ip => "192.168.2.1",
netmask => "255.255.0.0",
"node2":
mac1 => "78-e7-d1-24-5f-d0",
mac2 => "78:e7:d1:24:5f:d0",
ip => "192.168.2.2",
netmask => "255.255.0.0",
"node3":
mac1 => "78-e7-d1-24-5c-10",
mac2 => "78:e7:d1:24:5c:10",
ip => "192.168.2.3",
netmask => "255.255.0.0",
} #preseed

include dhcpd
} # node

This is puppet module for preseed and dhcpd.
/etc/puppet/modules/preseed/manifests/init.pp:
class dhcpd {
package { "isc-dhcp-server":
ensure => installed,
} #package
service { "isc-dhcp-server":
ensure => $ensure,
enable => true,
require => Package["isc-dhcp-server"],
} #service
file { "/etc/default/isc-dhcp-server":
ensure => present,
path => "/etc/default/isc-dhcp-server",
mode => 644,
content => template("preseed/isc-dhcp-server.erb"),
require => Package["isc-dhcp-server"],
notify => Service["isc-dhcp-server"],
} #file
} #class

define preseed ($mac1 = dflt, $mac2 = undef, $ip, $netmask) {
include dhcpd
file { "/var/www/preseed_$name.cfg":
ensure => present,
mode => 644,
content => template("preseed/preseed_web.cfg.erb"),
} #file
file { "/var/lib/tftpboot/pxelinux.cfg/01-$mac1":
ensure => present,
mode => 644,
content => template("preseed/pxe-config.erb"),
require => File["/var/www/preseed_$name.cfg"],
} #file
file { "/etc/dhcp/dhcpd.conf-$name":
ensure => present,
path => "/etc/dhcp/dhcpd.conf",
mode => 644,
content => template("preseed/dhcpd.conf.erb"),
require => Package["isc-dhcp-server"],
notify => Service["isc-dhcp-server"],
} #file
} #define

dhcpd.conf.erb:
...
<% name.each do |val| -%>
host <%= val %> { hardware ethernet <%= mac2 %>; fixed-address
<%= ip %>; }
<% end -%>

When I try to apply this configuration, I receive this message:

root@puppet:/# puppet agent --test --server=puppet.domain.com
info: Caching catalog for puppet.domain.com
err: Could not run Puppet configuration client: Cannot alias File[/etc/
dhcp/dhcpd.conf-node1] to ["/etc/dhcp/dhcpd.conf"]; resource ["File",
["/etc/dhcp/dhcpd.conf"]] already exists

What is the best way to create a configuration that applies only to
one node, but have to contain different parameters for each node.

Thanks.