Building a Private Cloud With System Center 2012 (Part 3)

by [Published on 1 Oct. 2013 / Last Updated on 1 Oct. 2013]

This article continues the walkthrough for building a private cloud by walking you through the construction of a logical network. After doing so, we will also be creating a new IP address pool that will service the logical network.

If you would like to read the other parts in this article series please go to:

Introduction

In my previous article in this series, I walked you through the process of creating various classifications of storage that will later be used in our private cloud. In this article, I want to continue the discussion by walking you through the creation of the virtual network that our private cloud will use.

Creating a Virtual Network

Begin the virtual network creation process by opening the Virtual Machine Manager console and clicking on the Fabric workspace. Next, expand the Networks container and click on Logical Networks. Right click on Logical Networks and select the Create Logical Network command from the resulting shortcut menu, as shown in Figure A.

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Figure A: Right click on the Logical Networks container and select the Create Logical Network command from the shortcut menu.

At this point, Windows will display the Create Logical Network Wizard. Enter a name and an optional description for the new logical network that you are creating. For the purposes of this article, I will be calling the network Service Network.

Before continuing on, make sure to select the Allow New VM Networks Created on This Logical Network to Use Network Virtualization check box. The Network Sites Within This Logical Network Are Not Connected check box should not be selected. You can see the proper configuration in Figure B. Click Next to continue.

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Figure B: Provide a name for your logical network and ensure that new VM networks are allowed to use it.

You will now be taken to the wizard’s Network Sites screen. This screen is used to associate VLANs and subnets to host groups. Click the Add icon and then select the host group that you previously created for your private cloud.

Now, locate the Associated VLANs and IP Subnets section of the dialog box. Click the Insert Row button. When you do, the wizard will prompt you to specify a VLAN and an IP subnet. For the purposes of this article, we don’t need to enter a VLAN. We do however, need to supply an IP subnet. You can enter any subnet that you want, but for the purposes of this article, I will be using 10.0.0.0/24. You can see what the fully configured dialog box looks like in Figure C.

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Figure C:
You must select a host group and associate a subnet with it.

Click Next and you will see a summary of the configuration options that you have selected. Click Finish to complete the creation of the logical network. When the process completes you can close the Jobs window.

IP Address Provisioning

If you have a basic understanding of networking, then you are no doubt familiar with the concept of using a DHCP server to provide IP addresses to hosts on a network. Normally when you set up a DHCP server, you are required to create a series of scopes, each of which acts as a pool of addresses that can be leased to network hosts.

As with any IP based network, we need to be able to allocate IP addresses to the virtual machines that will eventually be created in our private cloud environment. We will accomplish this by using System Center Virtual Machine Manager to create an IP address pool. The process that we will be using is very similar to that of provisioning a DHCP server.

Begin the process by selecting the Logical Networks container and then right clicking on the service network that you created in the previous section. Choose the Create IP Pool command from the resulting shortcut menu, as shown in Figure D. When you do, Windows will launch the Create Static IP Address Pool Wizard.

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Figure D: Right click on your service network and select the Create IP Pool command from the shortcut menu.

Before I walk you through the process of creating an IP address pool, I need to point out that you can use this pool to lease IPv4 addresses or IPv6 addresses, but not both. If you have a need for both address types you will have to create separate pools for them.

With that said, you should now be looking at the wizard’s Welcome screen. Enter a name for your IP address pool in the space provided. You can also enter an optional description. Be sure that the service network that you created is selected in the Logical Network drop down list.

Click Next, and you will be taken to the wizard’s Network Site page. For the purposes of this article, I will be assigning an IP address pool to the network site and subnet that we created earlier. As such, there is no need to use the Create a Network Site option. Instead, you can simply verify that the IP Subnet field reflects the IP subnet that you created earlier. Next, select the check box that corresponds to the host group that you previously created, as shown in Figure E. Click Next to continue.

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Figure E: You must associate a network site with your host group.

The next screen that you will see asks you to enter an IP address range. Once again, you can use any range that you want, so long as it does not overlap with any IP addresses that are currently in use on your network. Click Next to continue.

The next screen that you will see is the Gateway screen. Click Insert and then provide a default gateway address to be used by the computers in the IP address range. Click Next to continue.

You will now have to provide one or more DNS servers to be used by the IP address scope. Click Insert and then enter the IP address of your DNS server. Repeat this process if you have more than one DNS server. You can also specify a DNS suffix to use by clicking on the lower Insert button and then entering the DNS suffix into the space provided.

Click Next and you will be taken to the wizard’s WINS screen. WINS based name resolution is all but extinct, so you can simply click Next to skip this portion of the wizard.

You should now see a summary screen detailing the configuration options that you have entered for the IP address pool. Take a moment to verify the information, and assuming that everything is correct, click Finish.

Conclusion

In this article, I have walked you through the process of creating a logical network. However, our ultimate goal is to build a private cloud. As I explained early on in this series, private clouds are designed to be multi-tenant. In a multi-tenant environment it would be a huge security risk to allow everyone to use the same network infrastructure without isolating each tenant’s network traffic. As such, I will start the next article in the series by showing you how you can create Hyper-V virtual networks that overlay the logical network that we have just created.

If you would like to read the other parts in this article series please go to:

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