A Few Good Apps

Developer: Network team, did you order the Code upgrade?!

Operations Manager: You don’t have to answer that question!

Network Engineer: I’ll answer the question. You want answers?

Developer: I think I’m entitled!

Network Engineer: You want answers?!

Developer: I want the truth!

Network Engineer: You can’t handle the truth! Son, we live in a world that has VLANs, and those VLANs have to be plumbed by people with CLIs. Who’s gonna do it? You? You, Database Admin? I have a greater responsibility than you can possibly fathom. You weep for app agility and you curse the network. You have that luxury. You have the luxury of not knowing what I know, that network plumbing, while tragically complex, delivers apps. And my existence, while grotesque and incomprehensible to you, delivers apps! You don’t want the truth, because deep down in places you don’t talk about at parties, you want me on that CLI. You need me on that CLI. We use words like “routing”, “subnets”, “L4 Ports”. We use these words as the backbone of a life spent building networks. You use them as a punch line. I have neither the time nor the inclination to explain myself to a man who rises and sleeps under the blanket of infrastructure that I provide, and then questions the manner in which I provide it! I would rather you just said “thank you”, and went on your way. Otherwise, I suggest you pick up a putty session, and configure a switch. Either way, I don’t give a damn what you think you are entitled to!

Developer: Did you order the Code upgrade?

Network Engineer: I did the job that—-

Developer: Did you order the Code upgrade?!!

Network Engineer: YOU’RE GODDAMN RIGHT I DID!!

 

In many IT environments today there is a distinct line between the application developers/owners and the infrastructure teams that are responsible for deploying those applications.  These organizational silos lead to tension, lack of agility and other issues.  Much of this is caused by the translation between these teams.  Application teams speak in terms like: objects, attributes, provider, consumer, etc.  Infrastructure teams speak in memory, CPU, VLAN, subnets, ports.  This is exacerbated when delivering apps over the network, which requires connectivity, security, load-balancing etc.  On today’s network devices (virtual or physical) the application must be identified based on Layer 3 addressing and L4 information.  This means the app team must be able to describe components or tiers of an app in those terms (which are foreign to them.)  This slows down the deployment of applications and induces problems with tight controls, security, etc.  I’ve tried to describe this in the graphic below (for people who don’t read good and want to learn to do networking things good too.)

image

As shown in the graphic, the definition of an application and its actual instantiation onto networking devices (virtual and physical) is very different.  This causes a great deal of the slowed application adoption and the complexity of networking.  Today’s networks don’t have an application centric methodology for describing applications and their requirements.  The same can be said for emerging SDN solutions.  The two most common examples of SDN today are OpenFlow and Network Virtualization.  OpenFlow simply attempts to centralize a control plane that was designed to be distributed for scale and flexibility.  In doing so it  uses 5-tuple matches of IP and TCP/UDP headers to attempt to identify applications as network flows.  This is no different from the model in use today.  Network virtualization faithfully replicates today’s network constructs into a hypervisor, shifting management and adding software layers without solving any of the underlying problem.

What’s needed is a common language for the infrastructure teams and development teams to use.  that common language can be used to describe application connectivity and policy requirements in a way that makes sense to separate parts of the organization and business.  Cisco Application Centric Infrastructure (ACI) uses policy as this common language, and deploys the logical definition of policy onto the network automatically.

Cisco ACI bases network provisioning on the application and the two things required for application delivery: connectivity and policy.  By connectivity we’re describing what group of objects is allowed to connect to other groups of objects.  We are not defining forwarding, as forwarding is handled separately using proven methods, in this case ISIS with a distributed control plane.  When we describe connectivity we simply mean allowing the connection.  Policy is a broader term, and very important to the discussion.  Policy is all of the requirements for an application: SLAs, QoS, Security, L4-7 services etc.  Policy within ACI is designed using reusable ‘contracts.’  This way policy can be designed in advance by the experts and architects with that skill set and then reused whenever required for a new application roll-out.

Applications are deployed on the ACI fabric using an Application Network Profile. An application network profile is simply a logical template for the design and deployment of an applications end-to-end connectivity and policy requirements.  If you’re familiar with Cisco UCS it’s a very similar concept to the UCS Service Profile.  One of the biggest benefits of an Application Network profile is its portability.  They can be built through the API, or GUI, downloaded from Cisco Developer Network (CDN) or the ACI Github community, or provided by the application vendor itself.  They’re simply an XML or JSON representation of the end-to-end requirements for delivering an application.  The graphic below shows an application network profile.

image

This model provides that common language that can be used by developer teams and operations/infrastructure teams.  To tie this back to the tongue-in-cheek start to this post based on dialogue from “A Few Good Men”, we don’t want to replace the network engineer, but we do want to get them off of the CLI.  Rather than hacking away at repeatable tasks on the command line, we want them using the policy model to define the policy ‘contracts’ for use when deploying applications.  At the same time we want to give them better visibility into what the application requires and what it’s doing on the network.  Rather than troubleshooting devices and flows, why not look at application health?  Rather than manually configuring QoS based on devices, why not set it per application or tier?  Rather than focusing on VLANs and subnets as policy boundaries why not abstract that and group things based on those policy requirements?  Think about it, why should every aspect of a servers policy change because you changed the IP?  That’s what happens on today’s networks.

Call it a DevOps tool, call it automation, call it what you will, ACI looks to use the language of applications to provision the network dynamically and automatically.  Rather than simply providing better management tools for 15 year old concepts that have been overloaded we focus on a new model: application connectivity and policy.

**Disclaimer: I work as a Technical Marketing Engineer for the Cisco BU responsible for Nexus 9000 and ACI.  Feel free to disregard this post as my biased opinion.**

GD Star Rating
loading...

Video: Cisco ACI Overview

GD Star Rating
loading...

Oh, the Places You’ll Go! (A Cisco ACI Story)

In the fashion of my two previous Dr. Seuss style stories I thought I’d take a crack at Cisco Application Centric Infrastructure (ACI.)  Check out the previous two if you haven’t read them and have time to waste:

 

Horton Hears Hadoop: http://www.definethecloud.net/horton-hears-hadoop/

The App on the Crap (An SDN Story) http://www.definethecloud.net/the-app-on-the-crap-an-sdn-story/

 

 

 

 

 

 

Congratulations!

This is the time.

The network is changing!

The future is here!

 

With software controllers.

And virtualized widgets.

You can steer traffic

any direction you choose.

Packets are moving. They’ll flow where they flow.

And YOU are the gal who’ll decide where they’ll go.

 

You’ll look up and down paths.  Look ‘em over with care.

About some you’ll say, “No VOIP will go there.”

With an overlay net, and central control,

No packet will flow, down a not-so-good path.

 

And when packets travel

on suboptimal paths.

You’ll reroute those flows,

based on 5-tuple match.

 

Net’s opened wide

With central control.

 

Now net change can happen

and rapidly too

with net as central

and virtual too.

 

And when things start to happen,

don’t panic.  Don’t stew.

Just go troubleshoot.

All layers old, and the new.

 

OH!

THE PLACES YOU’LL GO!

 

You’ll be on your way up!

Packet’s moving in flight!

You’ll be the rock star

who set network right.

 

The network won’t lag, because of central control.

You’ll provision the pipes, avoid traffic black holes.

The packets will fly, you’ll be best of the best.

Wherever they fly, be faster than the rest.

 

Except when they don’t.

Because sometimes they won’t.

 

I’m sorry to say so

but, sadly it’s true

that Bang-ups

and Hang-ups

will happen to you.

 

You can get all hung up

in congestion / jitter.

And packets won’t travel.

Some will just flitter.

 

Applications will fail

with unpleasant time-outs.

And the chances are, then,

that you’ll start hearing shouts.

 

And when applications fail,

you’re not in for much fun.

Getting them back up

is not easily done.

 

You’ll need the app team, spreadsheets , security rules.

You’ll have to troubleshoot through disparate tools.

Find a way to translate from app language to net.

Map L3/L4 to app names, not done yet.

There are services too, that’s a safe bet.

 

Which route did it take, and which networks the problem?

Overlay, underlay, this network has goblins.

Congestion, and drops, latency jitter

Check with the software, than break out the splitter.

You’ll sort this out, you’re no kind of quitter!

 

It can get so confused

two networks to trace.

The process is slow, not what you want for a pace.

You must sort it out, this is business, a race.

What happened here, what’s going on in this place?

 

NO!

That’s not for you!

Those duct tape based fixes.

You’ll choose better methods.

Not hodge-podge tech mixes.

 

Look first at the problem,

what’s causing the issues?

What is it that net, is trying to do?

The app is the answer, in front of you.

 

The data center’s there to run applications!

To serve them to users, move data ‘cross nations.

To drive revenue, open up business models.

To push out new services, all at full throttle.

The application’s what matters.

Place it on a platter.

 

You’ll put the app into focus,

With some abstraction hocus-pocus.

 

You’ll use the language of apps.

To describe connectivity.

Building application maps,

to increase productivity.

 

Use a system focused on policy,

not new-fangled virtual novelty.

Look at apps end-to-end,

Not with the app is VM trend.

 

Whether virtual or physical, you’ll treat things the same.

From L2 to L3, or L4-7,

use of uniform policy, will be your new game.

Well on your way to networking heaven.

 

Start with a logical model, a connectivity graph.

One that the system, deploys on your behalf.

A single controller for policy enforcement.

Sure to receive security’s cheering endorsement.

Forget about VLANs, routes and frame formats,

no longer will networking be the app-deploy doormat.

 

You see to build networks for today and tomorrow,

don’t use band-aids stacked high as Kilimanjaro.

You’ll want to start with REMOVING complexity.

Anything else, just adds to perplexity.

 

Start at the top, in an app centric fashion.

on a system that knows to treat apps as its passion.

 

And will you succeed?

Yes! you will, indeed!

(98 and 3/4 percent guaranteed.)*

KID, YOU’LL MOVE MOUNTAINS!

 

So…

be your app virtual, physical or cloud

with services, simple, complex or astray,

you’re off to Great Places!

Today is your day!

ACI is waiting.

So…get on your way!

 

 

*This is intended as whimsical nonsense.  Any guarantees are null and void based on the complete insanity of the author.

**Disclaimer: I work for Cisco Systems with the group responsible for Nexus 9000 and ACI.  Please feel free to consider this post random vendor rhetoric.**

For more information on Cisco ACI visit www.cisco.com/go/aci

GD Star Rating
loading...

True Software Defined Networking (SDN)

The world is, and has been, buzzing about software defined networking. It’s going to revolutionize the entire industry, commoditize hardware, and disrupt all the major players. It’s going to do all that… some day. To date it hasn’t done much but be a great conversation, and more importantly identify the need for change in networking.

In its first generation SDN is a lot of sizzle with no flash. The IT world is trying to truly define it, much like we were with ‘Cloud’ years ago. What’s beginning to emerge is that SDN is more of a methodology then an implementation, and like cloud there are several implementations: OpenFlow, Network Virtualization and Programmable Network Infrastructure.

 

image

OpenFlow

Open Flow focuses on a separation of control plane and data plane. This provides a centralized method to route traffic based on a 5-tuple match of packet header information. One area OpenFlow falls short is in its dependence on the independent advancement of the protocol itself and the hardware support below. Hardware in the world of switching and routing is Application Specific Integrated Circuits (ASIC) based, and those ASICs typically take three years to refresh. This means that the OpenFlow protocol itself must advance, and then once stabilized silicon vendors can begin building new ASICs to be available three years later.

Network Virtualization

Network virtualization is a faithful reproduction of networking functionality into the hypervisor. This method is intended to provide advanced automation and speed application deployment. The problem here arises in the new tools required to manage and monitor the network, the additional management layer, and the replication of the same underlying complexity.

Programmable Network Infrastructure

Programmable network infrastructure takes the configuration of devices from human to machine CLI/GUI interfaces to APIs and programming agents. This allows for faster, more powerful and less error prone device configuration from automation, orchestration and cloud operating system tools. These advance the configuration of multiple disparate systems but are still designed based on network operating system constructs intended for human use, and the same underlying network complexities such as artificial ties between addressing and policy.

All of these generation 1 SDN solutions simply move the management of the underlying complexity around. They are software designed to operate in the same model, trying to configure existing hardware. They’re simply adding another protocol, or protocols, to the pile of existing complexity.

image

Truly software defined networks

To truly define the network via software you have to look at the entire solution, not just a single piece. Simply adding a software or hardware layer doesn’t fix the problem, you must look at them in tandem starting with the requirements for today’s networks: automation, application agility, visibility (virtual/physical) security, scale and L4-7 services (virtual/physical.)

If you start with those requirements and think in terms of a blank slate you now have the ability to build things correctly for today and tomorrow’s applications while ensuring backwards compatibility. The place to start is in the software itself, or the logical model. Begin with questions:

1. What’s the purpose of the network?

2. What’s most relevant to the business?

3. What dictates the requirements?

The answer to all three is the application, so that’s the natural starting point. Next you ask who owns, deploys and handles day two operations for an application? The answer is the development team. So you start with a view of applications in a format they would understand.

image

That format is simple provider/consumer relationships between tiers or components of an application. Each tier may provide and consume services from the next to create the application which is a group of tiers or components, not a single physical server or VM.

You take that idea a step further and understand that the provider/consumer relationships are truly just policy. Policy can describe many things, but here it would be focused on permit/deny, redirect, SLAs, QoS, logging and L4-7 service chaining for security and user experience.

image

Now you’ve designed a policy model that focuses on the application connectivity and any requirements for those connections, including L4-7 services. With this concept you can instantiate that policy in a reusable format so that policy definition can be repeated for like connections, such as users connecting to a web tier. Additionally the application connectivity definition as a whole could be instantiated as a template or profile for reuse.

You’ve now defined a logical model, based on policy, for how applications should be deployed. With this model in place you can work your way down. Next you’ll need network equipment that can support your new model. Before thinking about the hardware, remember there is an operating system (OS) that will have to interface with your policy model.

Traditional network operating systems are not designed for this type of object oriented policy model. Even highly programmable or Linux based operating systems have not been designed for object programmability that would fully support this model.  You’ll need an OS that’s capable of representing tiers or components of an application as objects, with configurable attributes. Additionally it must be bale to represent physical resources like ports as objects abstracted from the applications that will run on them.  An OS that can be provisioned in terms of policy constructs rather than configuration lines such as switch ports, QoS and ACLs. You’ll need to rewrite the OS.

As you’re writing your OS you’ll need to rethink the switching and routing hardware that will deliver all of those packets and frames. Of course you’ll need: density, bandwidth, low-latency, etc. More importantly you’ll need hardware that can define, interpret and enforce policy based on your new logical model. You’ll need to build hardware tailored to the way you define applications, connectivity and policy.  Hardware that can enforce policy based on logical groupings free of VLAN and subnet based policy instantiation.

If you build these out together, starting with the logical model then defining the OS and hardware to support it, you’ll have built a solution that surpasses the software shims of generation 1 SDN. You’ll have built a solution that focuses on removing the complexity first, then automating, then applying rapid deployment through tools usable by development and operations, better yet DevOps.

If you do that you’ll have truly defined networking based on software. You’ll have defined it from the top all the way down to the ASICs. If you do all that and get it right, you’ll have built Cisco’s Application Centric Infrastructure (ACI.)

For more information on the next generation of data center networking check out www.cisco.com/go/aci.

 

Disclaimer: ACI is where I’ve been focused for the last year or so, and where my paycheck comes from.  You can feel free to assume I’m biased and this article has no value due to that.  I won’t hate you for it.

GD Star Rating
loading...