=======================================
Using Bifrost with your own DHCP server
=======================================

The possibility exists that a user may already have a Dynamic Host
Configuration Protocol (DHCP) server on their network.

Currently Ironic, when configured with Bifrost in standalone mode, does not
utilize a DHCP provider. This would require a manual configuration of the
DHCP server to deploy an image. Bifrost utilizes dnsmasq for this
functionality; however, any DHCP server can be utilized. This is largely
intended to function in the context of a single flat network although
conceivably the nodes can be segregated.

What is required:

- DHCP server on the network segment
- Appropriate permissions to change DHCP settings
- Network access to the API and conductor. Keep in mind the iPXE image does not
support ICMP redirects.

Example DHCP server configurations
----------------------------------
In the examples below port 8080 is used. However, the port number may vary
depending on the environment configuration.

dnsmasq::

    dhcp-match=set:ipxe,175 # iPXE sends a 175 option.
    dhcp-boot=tag:!ipxe,undionly.kpxe,<TFTP Server Hostname>,<TFTP Server IP Address>
    dhcp-boot=http://<Bifrost Host IP Address>:8080/boot.ipxe

Internet Systems Consortium DHCPd::

    if exists user-class and option user-class = "iPXE" {
          filename "http://<Bifrost Host IP Address>:8080/boot.ipxe";
    } else {
          filename "undionly.kpxe";
          next-server <TFTP Server IP Address>;
    }


Architecture
------------

It should be emphasized that Ironic in standalone mode is intended to be used only
in a trusted environment.

::

                   +-------------+
                   | DHCP Server |
                   +-------------+
                          |
          +--------Trusted-Network----------+
                 |                    |
          +-------------+       +-----------+
          |Ironic Server|       |   Server  |
          +-------------+       +-----------+