Sean Roberts a79220badc docs update describing what is akanda

this includes the architecture section
as well as parts of other materials used for
demostrations. As the docs progress, the online
docs and demostration materials will be similar
or the same

Partially Implements: blueprint liberty-doc-updates

Change-Id: Icb89549f2bf69d7c7095cf5609456cf113cf1fa2

2015-09-02 15:16:49 -07:00

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What Is Akanda

Akanda is the only open source network virtualization solution built by OpenStack operators for real OpenStack clouds.

Akanda follows core principles of simple, compatible, and open development.

The Akanda architecture is broken down by describing the building blocks. The most important of those building blocks, the Akanda Rug, is a multi-process, multi-threaded Neutron Advanced Services orchestration service which manages the lifecycle of the Neutron Advanced Services. Akanda currently supports a Router Service Instance for Neutron Advanced Services. Akanda will support additional Neuton Advanced services such as Load Balancing, VPN, and Firewalls with the driver model.

High-Level Architecture

Akanda is a network orchestration platform that delivers network services (L3-L7) via Instances that provide routing, load balancing, firewall and more. Akanda also interacts with any L2 overlay - including open source solutions based on OVS and Linux bridge (VLAN, VXLAN, GRE) and most proprietary solutions - to deliver a centralized management layer for all OpenStack networking decisions.

In a canonical OpenStack deployment, Neutron server emits L3 and DHCP messages which are handled by a variety of Neutron agents (the L3 agent, DHCP agent, agents for advanced services such as load balancing, firewall, and VPN as a service):

When we add Akanda into the mix, we're able to replace these agents with a virtualized Service Instance that manages layer 3 routing and other advanced networking services, significantly lowering the barrier of entry for operators (in terms of deployment, monitoring and management):

Akanda takes the place of many of the agents that OpenStack Neutron communicates with (L3, DHCP, LBaaS, FWaaS) and acts as a single control point for all networking services. By removing the complexity of extra agents, Akanda can centrally manage DHCP and L3, orchestrate load balancing and VPN Services, and overall reduce the number of components required to build, manage and monitor complete virtual networks within your cloud.

Akanda Building Blocks

From an architectural perspective, Akanda is composed of a few sub-projects:

akanda-rug <http://github.com/stackforge/akanda-rug>

A service for managing the creation, configuration, and health of Akanda Service Instances in an OpenStack cloud. The :pyakanda-rug acts in part as a replacement for Neutron's various L3-L7 agents by listening for Neutron AMQP events and coalescing them into software router API calls (which configure and manage embedded services on the Service Instance). Additionally, :pyakanda-rug contains a health monitoring component which monitors health and guarantees uptime for existing Service Instances.

The rug really ties the room together

akanda-appliance <http://github.com/stackforge/akanda-appliance>

The software and services (including tools for building custom router images themselves) that run on the virtualized Linux router. Includes drivers for L3-L7 services and a RESTful API that :pyakanda-rug uses to orchestrate changes to router configuration.

akanda-neutron

Addon API extensions and plugins for OpenStack Neutron which enable functionality and integration with the Akanda project, notably Akanda router appliance interaction.

akanda-horizon

OpenStack Horizon rug panels providing management of the appliance

Software Instance Lifecycle

As Neutron emits events in reaction to network operations (e.g., a user creates a new network/subnet, a user attaches a virtual machine to a network, a floating IP address is associated, etc...), :pyakanda-rug receives these events, parses, and dispatches them to a pool of workers which manage the lifecycle of every virtualized router.

This management of individual routers is handled via a state machine per router; as events come in, the state machine for the appropriate router transitions, modifying its virtualized router in a variety of ways, such as:

Booting a virtual machine for the router via the Nova API (if one doesn't exist).

Checking for aliveness of the router via the REST API <appliance_rest> on the Service Instance.

Pushing configuration updates via the REST API <appliance_rest> to configure routing and manage services (such as iptables, dnsmasq, bird6, etc...).

Deleting virtual machines via the Nova API (e.g., when a router is deleted from Neutron).

The Router Service Instance (the Akanda Appliance)

Akanda uses Linux-based images (stored in OpenStack Glance) to provide layer 3 routing and advanced networking services. There is a stable image available by default, but it’s also possible to build your own custom Service Instance image (running additional services of your own on top of the routing and other default services provided by the project).

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