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Introduction

Each virtual machine network has a corresponding VLAN (or VXLAN with NSX). 

For private, external and public networks, Abiquo uses an ISC DHCP server to manage VLANs (or VXLANs). Abiquo recommends one DHCP server per physical datacenter registered in remote services. Additional DHCP servers may be incorporated in network virtualization solutions. The types of DHCP server configuration are as follows: 

  • Remote services DHCP server supplied with Abiquo or other compatible server
    • Configure datacenter DHCP as described below
      • For example, if you have many virtual machines in a datacenter, you might need a separate relay server to manage VLANs for the DHCP server
    • Add the DHCP service to Abiquo when creating or editing a datacenter
  • DHCP server incorporated in an integrated network virtualization system
    • In an Abiquo datacenter, create a logical device that will enable Abiquo to connect via the API of the network virtualization system to its DHCP server. See Manage Devices.
    • If the network virtualization system DHCP server is not available, Abiquo will fall back to the datacenter remote services DHCP server

For unmanaged networks, Abiquo does not use a DCHP server. So if your platform will only use unmanaged networks, you do not need to configure a DHCP server. However, you must provide the network addresses to the virtual machines outside of Abiquo.

To display the version of DHCP used by Abiquo, run the following command on the Abiquo remote services :

# /usr/sbin/dhcpd --version
isc-dhcpd-4.1.1-P1

Abiquo uses the DHCP server to: 

  • Manage the VLANs (or VXLANS), serving IP addresses to virtual machines
  • Serve static routes to virtual machines using the DHCP option
  • Serve information from the Chef integration using the vendor encapsulated options
    • The Chef integration is not available with NSX

How Abiquo Uses DHCP

The connections in DHCP are as follows:

  1. When you deploy a virtual machine, Abiquo (Remotes Services) supplies the network settings for the new VM to the DHCP Server.
  2. When the new virtual machine powers on, it broadcasts a DHCP request for network configuration.
  3. The hypervisor passes the DHCP request through a VLAN to the DHCP server.
  4. The DHCP server broadcasts a lease with the network configuration for the virtual machine over the same VLAN

DHCP Configurations

When configuring DHCP for a datacenter using the remote services, the possible DHCP configurations are:

Configuration

Capacity (per Datacenter)

DHCP Server only

< 200 VLANs

DHCP Server with DHCP Relay

< 1000 VLANs

DHCP Server with multiple DHCP Relays

> 1000 VLANs

The first configuration (DHCP Server only) is recommended only for test environments or small environments that will not be scaled up. The configuration with the DHCP relay server is recommended by Abiquo because it easy to set up and troubleshoot and it also scales well. 

Recommended Configuration

Abiquo recommends that you use a separate machine for VLAN support, not the DHCP Server included with the Remote Services. Remember to enter the DHCP Server address in the Remote Services for your physical datacenter in the Abiquo GUI. If you are using a DHCP Relay Server, do not configure support for VLANs on the DHCP Server. If you need to add more VLANs to this configuration, you can add more relay servers at a later date.

DHCP Server

The DHCP Server listens to all the VLANs. Abiquo recommends that you use a separate DHCP Server (not the Remote Services DHCP Service) in this configuration.

 

DHCP Server with DHCP Relay

The DHCP relay server listens to all the VLANs and forwards the DHCP requests to the DHCP Server.

 

DHCP Server with multiple DHCP Relays

Multiple DHCP relay servers allow you to create large networks in a hierarchical forwarding structure.

DHCP Installation Guide

The DHCP Relay Server (or DHCP Server if no relays are used) must be able to listen to VLANs. So it must be a separate physical machine or specially configured virtual machine.
If you wish to use a virtual machine, follow one of these configuration guides to prepare the virtual machine:

Then continue with the appropriate install section for your configuration

Install DHCP Server
  1. Install CentOS
  2. Install a separate DHCPD server

    yum install dhcpd
    
  3. Do the steps in Configuring a DHCP Server
DHCP Server with DHCP Relay

In this configuration you can use the DHCP Server on the Abiquo Remote Services machine. Or you can install a separate DHCPD server.

There are two ways to install the DHCP Relay Server: Abiquo ISO and manual install.

DHCP Server with Multiple DHCP Relays

In this configuration you can use the DHCP Server on the Abiquo Remote Services machine. Or you can install a separate DHCPD server.
See Manually Configuring Multiple DHCP Relay Servers.

  • By default, the manual configuration is for multiple networks with separate VLAN tags
  • There are a multitude of possible network configurations, so Abiquo does not recommend any specific configuration 

 

Configurations for Multiple Networks with Separate VLAN tags

These configurations are designed for multiple VLAN networks, which by definition have separate VLAN tags and isolate DHCP broadcasts. The server managing VLANs (DHCP Relay or DHCP Server) must have one VNIC or NIC with an IP address for each VLAN that will identify the VLAN to the DHCP ServerThe DHCP Server and VM communicate through broadcasts, which are also relayed, until the IP address of the VM is set, so there is no specific requirement for the IP address of the VNIC or NIC. However, it is recommended that the IP address range is not part of any other networks. For example, you could use the upper range of the management network. If you have complex requirements, you may need to adapt these configurations.

 

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                

Network Configuration for Virtualizing Abiquo
Automatically Configuring One DHCP Relay Server