An Introduction to Software Defined Networking with Windows Server 2016


Welcome to Microsoft Mechanics. Coming up, we look at the new software defined networking capabilities in Windows Server 2016. We’ll show you how you can use SDN to dynamically create, secure, and connect your network to meet the evolving needs of your apps, speed of the deployment of your workload, and contain security vulnerabilities from
spreading across your network. All while reducing your overall infrastructure cost. Microsoft Mechanics I’m joined by Greg Cusanza from the
Software-Defined Networking Team. Welcome. Thanks Matt, it’s great to be here. Software-defined Networking has been talked about for a while, but what are we really trying to solve for here? Well apps are innovating at a rapid pace. And often the complex physical infrastructure
can’t meet the needs of the changing apps. So rather than solve for this within the
constraints of the physical network, with SDN we virtualize the network
and all of its services so that apps are deployed faster and at a lower cost. Does SDN work with your existing physical network? Yes, it actually works on top of your
existing network infrastructure. Here’s how. I’ve mentioned the complexity of the physical network. Its complex because every application has a
different set of resource requirements. And, they have intertwined network dependencies. With SDN, we can reduce the complexity by creating a virtualization layer on top of the physical network. So that requirements of each of your
applications are met consistently and independent of the configuration
of the physical devices. This makes your applications
run more reliably and more securely. Even if you grow your physical network infrastructure, you don’t have to worry about breaking the apps. And your apps can immediately take
advantage of new resources. So what does this virtualization
layer you mentioned, consist of? Well I mentioned before that it comprises
the network and services. All of this is completely automated without needing to configure underlying physical infrastructure. Can we take a look? Absolutely. Let’s use a two-tier web application as an example. So in this illustration, you’ll see that it’s going to be a
public-facing application. So it needs to be isolated from the rest of my network while maintaining its internal connectivity. My users needed to be highly available to be able to scale out as load increases. So we need a load-balanced virtual IP to
spread across multiple instances. It needs connectivity to outside of its
isolation for Active Directory joining, or remote desktop access. And of course it needs to be secure. So let’s start with a blank slate. In this slate, i’m going to create a Virtual Network. The most basic unit of isolation. Then within the network, I’m going to add a Virtual Subnet for my web servers. And a Virtual Subnet for my file servers. Finally, I’m going to connect the actual VMs to the appropriate subnet for the role. Great. So let’s go to my script and we’ll do this in real-time. Normally we’d have to do this on the physical router, but here in this powershell script we’re going to first create the objects that represent the virtual network in the first section of the script. Then we’ll add two Virtual Subnets. Then, the last line applies these objects
to create the network. I’m going to run it right now. This first script just creates all of those assets? Exactly, and you can see it only
takes a second or two to run. And then the network’s been created. Now the next step is to attach the VM to
this network that I just created. Here I have a helper function that makes it a little bit easier so I can call it over and over again. I’m going to call it once for each of the VMs that I’m going to attach to this network. Two web servers and two file servers. Exactly. Let me go and do that. So now that it’s created we can switch
over to the first web server VM. And I can show basic connectivity here. I do an IP config to show that I got an IP address. i’ll do a ping to show that I have basic
connectivity to another VM. And just to make sure that we really have connectivity, I’m going to open up Internet Explorer and connect to the web server on that second VM. Great, that was incredibly simple,
but what are some of the other important components within the
Virtual Network environment? Well we’ve added one already. So you saw me create two subnets. In order for these two subnets to be
able to talk to each other, distributed routing is added automatically
to connect the two subnets together. Another service that is in SDN
Windows Server 2016 provides is the software load balancer. It’s based on the load balancer technology in Azure. Now it’s included in Windows Server 2016 data center. So load balancing is critical to cloud workloads, so they can take advantage of the
elasticity of the Cloud? Right, let me show you how we do that. So the first thing that we’re going to do in our
network is we’re going to add a virtual IP. This will load balance to
the two web server VMs that I just created. Later on if we decide to add a third VM, the load balancer will automatically use it, too. Let’s jump back into the script. What I’m going to do here is,
first in the script I’m going to create a FrontEndIPConfiguration. That’s what’s going to contain
the VIP for the application. Then I’m going to create a BackEndAddressPool to contain the VMs. And then create a set of LoadBalancingRules that will kind of tie the two together on
port 80 for my web request. You mentioned VIP being the virtual IP? Yeah exactly, that’s the one address that the clients of the application use to connect in. One command will make it happen,
so let’s run this script as well. There we go. So we created the load balancer configuration. The next thing we need to do is add our VMs to it. So we have to do this once for each
of the web server VMs. So I add VM #1 and then I add VM #2. Let’s run that. This will also run for just a second or two. Now that it’s done we can go in and we can actually check to make sure that it’s actually working. So I put a uniquely colored webpage
on each of the web servers. So each time I refresh now you’ll see a
different color comes back. It’s the best way to show that were
actually load balancing. Load balancing across those two VMs? Exactly. Then, I can go to the actual app that I’ve deployed. Very popular blog. Yeah, thanks. So very few applications are as simple as this. So what happens if I’ve got a database workload that is outside of my Software Defined Network? Yeah, for that we have what we
call multi-tenant Gateways. There are three modes that the Gateway works in. The first is basic layer 3 forwarding for routing between Virtual Networks and VLANs. The next is site to site VPN for connecting the virtual network directly to remote sites. And then there’s GRE tunneling for maintaining address base
isolation within your data center. You can combine these to achieve the level of connectivity that you need. I can show you my script again by going back to the demo environment. For this application we’re going to connect
our virtual network to our VLAN with L3 forwarding. Here we’re starting in the web server VM. This time we’re actually trying to go
out from the network. We started a ping to show that it doesn’t
yet have outbound connectivity. So, out from the virtual networks to a physical network? Yes exactly. So now, let’s go back to the script. I’m going to run it right away so we can
get the settings applied. And then while the settings are actually
propagating out to the gateways, I’m going to take a little bit more of a look at this script. So up top I have the virtual network. And I have the physical network which contains the VLAN that I’m going to be connecting to. Then I take the two and I create a virtual
gateway on the virtual network. Then I configure a connection to the
VLAN that I mentioned. That VLAN was created by my network admin
for me to be able to connect to it. So you would need to coordinate with the
networking team to make this a reality? Yeah that’s right, in this case I do have to do that. But, I also have network address translation available as an option that I could use if I want. A Network Address Translation would make it so that I could use a completely private address space for my VMs and not have to talk to the network admin in order to get that address space allocated to me. The SDN environment would handle the
translation from one to the other. Let’s see now if the settings have been applied. You can see the ping is still timing out. And within a second or two. There we go, so it’s now established the connectivity from within the Virtual Network to the outside. So I can go in and I can do a trace route to see that it goes first to the distributed
router that I mentioned, then to the virtual gateway that I just created, the physical gateway, then onto my destination. I now have the full ability to send traffic
in and out of the Virtual Network. From the physical world into the virtual world? Yeah exactly. Just like it was a real network. Awesome, so establishing connectivity like this
surely opens up your network to good traffic and bad traffic, does it not? Yeah, it’s the risk customers face
every day when they deploy an application. The first way to address this is using
the distributed firewall to apply the security rules to the virtual subnet, so that every VM in the subnet gets the
right set of rules automatically. Even if we add another VM at a later time, it will get automatically the right set of rules. So we can go back to the script and
I can show you this as well. So in the script I have a helper function to make it easy to define the rules over and over again. We call the helper once for each rule. First defining the inbound rules. And then we define separately the outbound rules that will then allow it to talk to the file server. Let’s run this. We save into what we call an Access Control List. And then the last thing left to do is
actually apply it to the Subnet. That was just one quick script that ran there. Now we’ve put it on our first subnet where
the web servers are located. Now let’s go to one of the web servers
and test the results. So I can do an ipconfig/flesh to make
sure we do fresh DNS request. So I do a ping sofs. You can see that I got an address for that machine, but the ping itself is blocked as we would expect because I created the rule to block that. I’m now going to the file explorer, open up the UNC path to my file server. Because the file servers is where
my web pages are stored I need to be able to get to that. That traffic is allowed. After a few seconds here it went to it’s authentication. You see it gets in and I can go down, double-click that and you can see the
files that are in that file share. I block the traffic I didn’t want,
but allowed the traffic that I did want. So I can go up and show that inbound that
the web server is still working. Great, and all very configurable
very granular settings within PowerShell? Yeah, exactly. So this will do a lot to reduce the attacked servers and prevent attacks from spreading within the network. But, what if I’m already depending on network appliances or existing security
technology from an external source? Yeah earlier we discussed how a distributed routing gets added automatically to connect the subnets. You have control over that router. In order to be able to send traffic to any virtual
appliance connected to the Virtual Network. As long as that appliance runs on hyper-v, we call this feature “U-defined routing or UDR”. So we’re going to utilize U-defined routing to insert a Linux virtual appliance in our network for traffic analysis. So we’ll go back to the script, here. And so it’s as simple as creating a routing table, specifying the routing table in the Virtual
Subnets where you want it applied. In this case our route rule says to send
any traffic for the 192.168 Subnet to the virtual appliance at the .254 address. We’re then applying that route table to our two Subnets. Before we run, let’s bring up the
Linux appliance on the right. You can see that it has some basic
background traffic that it’s sending itself. But now soon as we run the script watch
what happens on the right side. It’ll take a second to apply and there you go. Now you can see all the traffic that’s
destined for that .2 subnet is now going through this Linux VM to be able to process, forward on, and do whatever it wants to it. It has full control over that now. And Linux runs great on hyper-v as we know? Linux and BSD as well. Great so there’s lots of security vendors
out there with hyper-v appliances But there’s also appliances that aren’t just
for security, can I use those as well? Of course, user-defined routing isn’t just for security. Pick your favorite load balancer, your favorite WAN opitmizer, VPN, you name it. If it runs on hyper-v as a VM,
they can use it in the virtual network with UDR. So in summary, we saw SDN provide all of the network resources that our two tier app needs, With all the required security. That’s right and what’s more,
we did it all with the SDN capabilities included in Windows Server 2016 Data Center. We did not have to touch a single
physical device in this configuration. So how do you recommend people get started? So need to be on hyper-v in
Windows Server 2016 Data Center. But, you can learn more about how to plan and implement into your deployment at the link below. Thanks Greg for joining us and helping us learn a little more about Software-Defined Networking. And of course, keep watching Microsoft Mechanics
for the latest in tech updates. Bye for now. Microsoft Mechanics www.microsoft.com/mechanics

5 thoughts on “An Introduction to Software Defined Networking with Windows Server 2016

  1. Have a question about Software Defined Networking? Ask the experts on the Microsoft Tech Community:
    https://techcommunity.microsoft.com/t5/Windows-Server-Networking/bd-p/Windows-Server-Networking

    Find more resources on Software Defined Networking go here:
    https://www.microsoft.com/en-us/cloud-platform/software-defined-networking

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