CloudStack extra DHCP option support

Feature Reference

CLOUDSTACK-9776 - Getting issue details... STATUS

Branch

https://github.com/apache/cloudstack/pull/2049

Introduction

Cloudstack currently does not allow users to set extra DHCP options. This feature will add support for adding extra (user defined) DHCP options on every nic of a VM in Cloudstack.

CloudStack currently supports the following DHCP options:

• 1: netmask

• 3: router

• 6: dns-server

• 15: domain name

Purpose:

This design document proposes an extension of the deploy, update VM and plug nic command in order to support extra DHCP options per nic.

References

• TBD

Document History

Feature Specifications

Summary: This design document proposes:

• Extension of deploy, update VM and plug nic command.
• Extension of the DhcpServiceProvider interface
• Extension of the CloudStack database

Use cases

Beside the standard DHCP options which are provided by Cloudstack (netmask, router, dns-server and domain name) users can now specify extra DHCP options which are needed on their VM’s. For example the DHCP option for MTU (26).

Architecture and Design description

Storing the extra DHCP options

The extra dhcp options need to be stored in the database (db). We propose to create a nic_extra_dhcp_options containing the nic ref (=nic_id), dhcp code (=code int), dhcp value (=value text).

Alternatives:

1. Store as metadata of NicVO, all options in one entry, encoded in json

2. Store as metadata of NicVO, one entry per option, prefixed with eg "extra-dhcp-", and add a listByKeyPrefix method to the DAO

Extension of DhcpServiceProvider

We provide a new capability named EXTRA_DHCP_OPTIONS. Every dhcp service provider who supports extra dhcp options should add this capability to it’s capabilities list.

Furthermore we create a new method in the DhcpServiceProvider interface named:  setExtraDhcpOptionsForVM(...., Map<Integer, String> dhcpOptions)

dhcpOptions is a map for which the key contains the dhcp option code and the value for this key is the dhcp option value.

Extension of API

The deployVirtualMachine, updateVirtualMachine and addNicToVirtualMachine commands need to be extended with a parameter to pass the extra DHCP options. We allow the user to specify the DHCP options with their option code or the name of the DHCP options.

deployVirtualMachine
 https://cloudstack.apache.org/api/apidocs-4.9/apis/deployVirtualMachine.html
Creates and automatically starts a virtual machine based on a service offering, disk offering, and template.

ADD following optional parameter :
 

This API extension allows to pass DHCP options as a list of key-value pairs, for every NIC of the newly deployed VM (or for the primary NIC only). Furthermore, we allow the user to specify the dhcp option with the dhcp option name (example 2) or with the dhcp option code (example 1).

updateVirtualMachine

 https://cloudstack.apache.org/api/apidocs-4.9/apis/updateVirtualMachine.html
Updates properties of a virtual machine. The VM has to be stopped and restarted for the new properties to take effect. UpdateVirtualMachine does not first check whether the VM is stopped. Therefore, stop the VM manually before issuing this call.

ADD following optional parameter :

Dhcp options that are not specified (and were previously set) get deleted.
Other operations same as deployVirtualMachine.

addNicToVirtualMachine

https://cloudstack.apache.org/api/apidocs-4.8/user/addNicToVirtualMachine.html
Adds VM to specified network by creating a NIC

ADD following optional parameter :

The dhcp options will be set on the newly added nic. The option code can be passed as a code (Example 1) or as a name (Example 2).

listNics

We want to return the extra DHCP options that are set for each nic.

Mapping of DHCP option name to DHCP code

Below you find a proposed list of how the DHCP option name maps to the option code (based on dnsmasq https://github.com/imp/dnsmasq/blob/master/src/dhcp-common.c ):

UI

It is proposed not to include UI development in the first iteration.

IP Clearance

No changes

Usage Impact

No impact on other components