Data bag and Attribute driven DHCP server.

• Supports setting up Master/Master isc DHCP failover.
• Includes Support for ddns
• Includes LWRPs for managing hosts, groups and subnets.
• Use databags or attributes + wrapper cooks to manage dhcp server Example

Large parts were borrowed from work initially done by Dell, extended by Atalanta Systems and reworked by Matt Ray and Chef. Big thanks to all of them.

• Debian / Ubuntu
• CentOS and derivatives

• 12.7+

• only setup to handle ipv4

The node will install and configure the dhcp-server application. Configuration is through various dhcp_X bags, and the current role/environment

Almost everyone of the parameters and options are able to be overrode in the host/group/network scope these are general defaults for the server.

Check out the man page for details on dhcpd.conf options/params.

These are all just k/v entries in the global params hash. All values are type: String

RHEL Platforms*

Debian Platforms

Data bags drive the lionshare of the dhcp configuration. Beyond the global settings. It is not required to configure any bags other than dhcp_networks to get up and running, But if you want to statically map a network or have handy Host names provisioned by dhcp you will have to add either dhcp_groups/dhcp_hosts bags and items.

You can generate example bags by using these handy commands

knife data bag create dhcp_networks
knife data bag create dhcp_groups
knife data bag create dhcp_hosts
knife data bag from file dhcp_networks examples/data_bags/dhcp_networks
knife data bag from file dhcp_groups examples/data_bags/dhcp_groups
knife data bag from file dhcp_hosts examples/data_bags/dhcp_hosts

Looked up via node[:dhcp][:networks_bag]. Describes networks this dhcp server should be configured to provide services for. Per-network options can be provided as an array of strings where each string is a dhcp option. Make sure you escape "'s properly as dhcpd is touchy about the format of values.

{
  "id": "192-168-1-0_24",
  "routers": [ "192.168.1.1" ],
  "address": "192.168.1.0",
  "netmask": "255.255.255.0",
  "broadcast": "192.168.1.255",
  "range": "192.168.1.50 192.168.1.240",
  "options": [ "time-offset 10" ],
  "next_server": "192.168.1.11"
}

Looked up via node[:dhcp][:grougroups] Items for this bag are group entries as per the man page. Groups are sets of machines that can be configured with common parameters. A group can be bare. I.e. Contains no host or parameters entries whatsover, and just defines options.

The only required key in a host def is the "mac": key. Everything else is optional

Example Group Bag

{
  "id": "test",
  "pxe":  "ubuntu-precise",
  "parameters": [
    "use-host-decl-names on",
    "max-lease-time 300",
    "default-lease-time 120",
    "next-server \"someplace\""
  ],
  "hosts": {
    "some-vm": {
      "parameters": [  ],
      "mac": "11:22:33:44:55:66",
      "ip": "192.168.1.111"
    },
    "another-host": {
      "mac": "22:33:44:55:66:77"
    }
  }
}

There are a few keys that merit more discussion:

Groups in isc-dhcp can define lists of hosts. In this example we are using the use-host-decl-names on tell dhcp to use the "some-vm" and "another-host" entries as the host-name for these clients. As well as setting other per-group parameters.

Each Host in the hosts Hash can have a number of settings, but the only required setting is "mac": the mac address for the host.

Dhcp hosts bag is looked up via node[:dhcp][:hosts_bag], and contains Host Items.

Example Most Basic host:

{
  "id": "vagrant-vm",
  "hostname": "vagrant.vm",
  "mac": "08:00:27:f1:1f:b6",
}

Example Complex host:

{
  "id": "pxe_test-vm",
  "hostname": "pxe_test.vm",
  "mac": "08:00:27:8f:7b:db",
  "ip": "192.168.1.31",
  "parameters": [ ],
  "options": [ ],
  "pxe": "ubuntu-precise"
}

Manipulate host entries in dhcpd

Add a Node

dhcp_host "myhost" do
  hostname   "somebox.foobar.com"
  macaddress "08:00:27:f1:1f:b6"
  ipaddress  "192.168.1.22"
  options   [ "domain-name-servers 8.8.8.8" ]
end

Remove a node

dhcp_host "myhost" do
  action :remove
  hostname "somebox.foobar.com"
end

If you undefine an entry it will also get removed.

hosts_data = {
  "some-vm"=> {"parameters"=>[], "mac"=>"11:22:33:44:55:66", "ip"=>"192.168.1.111"},
  "another-host"=>{"mac"=>"22:33:44:55:66:77"}}
}

dhcp_group "some_group" do
  parameters [ "default-lease-time 120", "next-server \"someplace\""]
  hosts hosts_data
end

dhcp_subnet "192.168.1.0" do
  pool do
    range ["192.168.1.100 192.168.1.200", "10.33.66.10 10.33.66.100"]
  end
  netmask "255.255.255.0"
  broadcast "192.168.1.255"
  options [ "time-offset 10" ]
  next_server "192.168.1.11"
  routers "192.168.1.1"
  evals [ %q|
    if exists user-class and option user-class = "iPXE" {
      filename "bootstrap.ipxe";
    } else {
      filename "undionly.kpxe";
    }
  | ]
end

dhcp_shared_network 'mysharednet' do
  subnet '192.168.1.0' do
    pool do
      range ['192.168.1.100 192.168.1.200', '10.33.66.10 10.33.66.100']
    end
    netmask '255.255.255.0'
    broadcast '192.168.1.255'
    next_server '192.168.1.11'
    routers '192.168.1.1'
    evals [ %q|
      if exists user-class and option user-class = "iPXE" {
        filename "bootstrap.ipxe";
      } else {
        filename "undionly.kpxe";
      }
    | ]
  end
  subnet '10.0.2.0' do
    broadcast '10.0.2.254'
    netmask '255.255.255.0'
    pool do
      range ['10.0.2.50 10.0.2.240']
    end
  end
end

Manage dhcp classes

Add a Node

dhcp_class 'ignorehosts' do
  match 'hardware'
  subclass '1:10:bf:48:42:55:01'
  subclass '1:10:bf:48:42:55:02'
end

If you undefine an entry it will also get removed.

Testing uses ChefDK 0.13.21. Assuming it's installed and you've initialized your shell with chef shell-init you can run rake to run testing.

https://github.com/spheromak/dhcp-cook

• Jacob McCann
• Jesse Nelson
• Matt Ray

• 2013 Jesse Nelson
• 2011 Atalanta Systems
• 2011 Dell, Inc.
• 2011 Opscode, Inc.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.