1. Implementing Network Load Balancing
Presentation: 50 minutes
After completing this module, the students will be able to:
Describe Network Load Balancing (NLB).
Explain how to configure an NLB cluster.
Explain how to plan an NLB implementation.
Required materials
To teach this module, you need the Microsoft® Office PowerPoint® file 20412C_MVA_09.pptx
Important:
We recommend that you use PowerPoint 2007 or a newer version to display the slides for this course. If you use PowerPoint Viewer or an older version of PowerPoint, all the features of the slides might not display correctly.
Preparation Tasks
To prepare for this module:
Read all of the materials for this module.
Practice performing the demonstrations.
Preparation for demonstrations
For this module, you will use the available virtual machine environment. Before you begin the module, you must complete the following steps:
On the host computer, click Start, point to Administrative Tools, and then click Hyper‑V Manager.
In Hyper‑V Manager, click 20412C‑LON‑DC1, and in the Actions pane, click Start.
In the Actions pane, click Connect. Wait until the virtual machine starts.
Sign in using the following credentials:
User name: Adatum\Administrator
Password: Pa$$w0rd
Repeat steps 2 through 4 for 20412C-LON-SVR1 and 20412C-LON-SVR2.
Note: When you are done with demonstrations in this module, revert all virtual machines to their initial checkpoint.
Module 9
Implementing Network Load Balancing

2. Planning an NLB Implementation
20412C
Module Overview
9: Implementing Network Load Balancing
Planning an NLB Implementation
Provide a brief overview of the module contents.

3. Overview of NLB

4. Lesson 1: Overview of NLB
20412C
Lesson 1: Overview of NLB
9: Implementing Network Load Balancing
NLB Features in Windows Server 2012 and Windows Server 2012 R2
Provide a brief overview of the lesson contents.

5. Scalable high-availability technology
What Is NLB?
9: Implementing Network Load Balancing
Scalable high-availability technology
Balances traffic based on node utilization
New traffic will be directed to the node that is being utilized the least
You can configure NLB to preference some nodes over others
Used with stateless applications such as:
Web tiers of multi-tier applications
Not used with stateful applications such as:
Traditional file servers
Database servers
Ask the students if they use NLB in their environments. Ask the students if they use hardware load balancers or NLB. Students that work in heterogeneous environments are more likely to use hardware devices for NLB.
NLB is less complicated to configure than failover clustering, but students need to be reminded that NLB is a solution that is appropriate only for specific applications.

6. How NLB Works? Network Load Balancing Host Dedicated IP: 10.1.1.2
9: Implementing Network Load Balancing
Client
Accept? No
Yes
Network Load Balancing Host
Dedicated IP:
Virtual IP:
Dedicated IP:
Dedicated IP:
Dedicated IP:
When describing the topic, provide examples of a hypothetical NLB cluster used for load-balancing web traffic. Describe how traffic will be directed in the case where one or more nodes is being heavily utilized, and how this contrasts with a round robin solution, where node utilization is not taken into account.

7. How NLB Works with Server Failures and Recovery?
9: Implementing Network Load Balancing
NLB cluster heartbeats are transmitted every second between nodes in a cluster
Convergence occurs when:
A node misses five consecutive heartbeats, at which time it is automatically removed from an NLB cluster
A node that was member of a cluster returns to functionality
An administrator adds or removes a node manually
Describe the process by which a cluster node is removed from a cluster. Explain that traffic that is directed to the failed host prior to convergence occurring will encounter an error, and that the client will have to reconnect to establish a session to an active node.
Discuss with the students the difference between server failure and application failure, and why they should consider deploying an advanced monitoring solution such as Microsoft® System Center Operations Manager if they are responsible for managing an NLB cluster that hosts a critical application.

8. NLB Features in Windows Server 2012 and Windows Server 2012 R2
20412C
NLB Features in Windows Server 2012 and Windows Server 2012 R2
9: Implementing Network Load Balancing
Use 35 new NLB Windows PowerShell cmdlets to manage all aspects of NLB configuration
Use NlbCluster noun to manage the cluster
Use NlbClusterNode noun to manage individual nodes
Remind students that all management tasks on Windows Server® 2012 and Windows Server® 2012 R2 can be performed through Windows PowerShell®. This enables them automate many processes that once had to be performed manually. Some tasks, such as setting port rule node weight, can only be performed using Windows PowerShell, and cannot be performed using Network Load Balancing Manager.
To see the list of Windows PowerShell cmdlets for NLB, you can use the get-command –module NetworkLoadBalancingClusters command.

9. Configuring an NLB Cluster

10. Lesson 2: Configuring an NLB Cluster
9: Implementing Network Load Balancing
Network Considerations for NLB
Provide a brief overview of the lesson content.

11. Deployment Requirements for NLB
20412C
Deployment Requirements for NLB
9: Implementing Network Load Balancing
All hosts must be on the same subnet
All adapters must be configured as either unicast or multicast
Only TCP/IP protocol can be used on adapters
All adapters used with NLB must be configured with static IP address
When you are discussing the requirements for NLB configuration, one of the main issues will be the requirement that all hosts are on the same subnet. Describe to students how they can deploy NLB clusters across subnets using Domain Name System (DNS) round robin.
Also, discuss the requirement that static IP addresses must be used with adapters that participate in NLB clusters.

12. Demonstration: Deploying NLB
20412C
Demonstration: Deploying NLB
9: Implementing Network Load Balancing
In this demonstration, you will see how to create a Windows Server 2012 R2 NLB cluster
Preparation Steps
For this demonstration, you will need the 20412C-LON-DC1, 20412C-LON-SVR1, and 20412C-LON-SVR2 virtual machines. Sign in as Adatum\Administrator and the password Pa$$w0rd.
Demonstration Steps
Create a Windows Server 2012 R2 NLB cluster
Sign in to LON-SVR1 as Adatum\Administrator with the password Pa$$w0rd, and on the taskbar, click the Server Manager icon.
In the Server Manager console, click the Tools menu, and then click Windows PowerShell ISE.
In the Windows PowerShell ISE window, enter the following command, and then press Enter:
Invoke-Command -Computername LON-SVR1,LON-SVR2 -command {Install- WindowsFeature NLB,RSAT-NLB}
Enter the following command, and then press Enter:
New-NlbCluster -InterfaceName "Ethernet" -OperationMode Multicast - ClusterPrimaryIP ClusterName LON-NLB
Add-NlbClusterNode -InterfaceName "Ethernet" -NewNodeName "LON-SVR2" - NewNodeInterface "Ethernet"
In the Server Manager console, click the Tools menu, and then click Network Load Balancing Manager.
Verify that nodes LON-SVR1 and LON-SVR2 display with the status of Converged for the LON-NLB cluster.
Right-click the LON-NLB cluster, and then click Cluster properties.
In the LON-NLB( ) dialog box, on the Cluster Parameters tab, verify that the cluster is set to use the Multicast operations mode.
On the Port Rules tab, verify that there is a single port rule named All that starts at port 0 and ends at port for both Transmission Control Protocol (TCP) and User Datagram Protocol (UDP), and uses Single affinity.
Click OK to close the dialog box.
(More notes on the next slide)

13. Configuration Options for NLB
9: Implementing Network Load Balancing
Port rules determine how traffic is directed to cluster nodes depending on TCP or UDP port
Multiple hosts
Single host
Disable port range
Affinity settings determine how reconnection occurs
None
Single
Class C
Explain to the students the types of situations where they would want to configure the single affinity setting—for example, on an e-commerce web application where it is necessary to ensure that a disconnected client reconnects to the same session.
When you discuss port rules, describe the types of situations where you would use port rules other than the default port rule. For example, you can load balance all incoming requests on port 80 across all nodes in the cluster, and direct all incoming requests on port 5678 to a single host.
Discuss host parameters and the types of applications where you might configure different host parameters.
Point out that as a security measure, you can configure the cluster with port rules only on specific ports. Connection attempts on ports other than those used by the cluster nodes will be dropped automatically.

14. Demonstration: Configuring NLB Affinity and Port Rules
9: Implementing Network Load Balancing
In this demonstration, you will see how to:
Configure affinity for NLB cluster nodes
Configure NLB port rules
After you complete the demonstration, revert virtual machines 20412C-LON-DC1, 20412C-LON-SVR1, and 20412C-LON-SVR2.
Preparation Steps
For this demonstration, you will need the 20412C-LON-DC1, 20412C-LON-SVR1, and 20412C-LON-SVR2 virtual machines. Sign in as Adatum\Administrator with the password Pa$$w0rd.
Demonstration Steps
Configure affinity for NLB cluster nodes
On LON-SVR2, on the taskbar, click the Windows PowerShell icon.
At the Windows PowerShell prompt, type the following commands, pressing Enter after each command:
Cmd.exe
Mkdir c:\porttest
Xcopy /s c:\inetpub\wwwroot c:\porttest
Exit
New-Website -Name PortTest -PhysicalPath "C:\porttest" -Port 5678
New-NetFirewallRule -DisplayName PortTest -Protocol TCP -LocalPort 5678
Configure NLB port rules
On LON-SVR1, in Server Manager, click Tools, and then click Network Load Balancing Manager.
In the Network Load Balancing Manager console, right-click LON-NLB, and then click Cluster Properties.
In the LON-NLB( ), on the Port Rules tab, select the All port rule, click Remove, and then click OK to close the LON-NLB( ).
In the LON-NLB( ), on the Port Rules tab, click Add.
In the Add/Edit Port Rule dialog box, enter the following information, and then click OK:
Port range: 80 to 80
Protocols: Both
Filtering mode: Multiple Host
Affinity: None
Click OK to close the LON-NLB( ).
On the Port Rules tab, click Add.
Port range: 5678 to 5678
Filtering mode: Single Host
In the Network Load Balancing Manager console, right-click LON-SVR1, and then click Host Properties.
On the Port Rules tab, click the port rule that has 5678 as the Start and End value, and then click Edit.
Click the Handling priority value, and change it to 10.
Click OK twice to close the Add/Edit Port Rule dialog box and the Host Properties dialog box.
(More notes on the next slide)

15. Network Considerations for NLB
9: Implementing Network Load Balancing
Unicast mode
Suitable for clusters that have multiple network adapters
Multicast mode
Suitable for NLB clusters that have single network adapters
Network devices must support multicast MAC addresses
IGMP multicast
Improves switch performance
Requires a network switch that supports this functionality
Ask the students what solution they would use if they needed to support an NLB cluster where they would need to perform node management tasks from remote networks, and where Windows Server 2012 and Windows Server 2012 R2 servers only have one network adapter.
The answer is that they must use multicast mode as unicast mode with one adapter only allowing management from local subnet.

16. Planning an NLB Implementation

17. Lesson 3: Planning an NLB Implementation
20412C
Lesson 3: Planning an NLB Implementation
9: Implementing Network Load Balancing
Considerations for Upgrading NLB Clusters
This lesson describes different aspects of NLB implementation, such as designing support for NLB, options for securing and scaling NLB, and the considerations for upgrading NLB clusters.

18. Designing Applications and Storage Support for NLB
9: Implementing Network Load Balancing
Each node in an NLB cluster needs to have the same configuration
Each node needs access to the same consistent application data
Use IIS shared configuration to ensure that web application configuration is consistent across NLB nodes
Use CSVs to host shared application and configuration data for NLB applications
When you are discussing the storage of application data and application configuration data, remind the students that they must ensure that clients that are accessing the application must receive the same information, regardless of the node through which they access the information. If each node presents different information, it will be impossible for the user to know which information is accurate.

19. Considerations for Deploying an NLB Cluster on Virtual Machines
9: Implementing Network Load Balancing
Configure virtual machines with multiple network adapters
Configure one network adapter on each node member to use a shared private network switch
Configure the NLB cluster to use unicast mode and enable MAC address spoofing on Hyper-V host
Use the shared private network switch for cluster communication
When NLB nodes span multiple sites, use network virtualization to separate the cluster network
Discuss with the students how to deploy NLB on virtual machines. Discuss virtual machine network configuration, and why choosing unicast over multicast results in performance improvements. When dealing with the question of why you would use multiple NLB virtual machines when you can configure Hyper-V to provide a redundant environment on which to host virtual machines, remind the students that virtual machine operating systems and applications can still experience software-based failures, even when hosted in a highly redundant hardware environment. A cluster node that encounters a Stop error is just as unavailable when hosted on a virtual machine, as it is when hosted on traditionally deployed hardware.

20. Considerations for Securing NLB
9: Implementing Network Load Balancing
Use NLB cluster port rules to discard traffic not related to cluster applications
Use firewall rules on cluster nodes to drop traffic not related to cluster applications or node management
Configure applications to respond only to traffic that is addressed to the cluster
Use SANs to create certificates that support the application name and node names
Implement principle of least privilege to ensure that only authorized users have appropriate permissions on nodes
When you discuss why you use both port rules and firewall rules, remind the students that cluster nodes can be addressed both indirectly through the NLB cluster, and directly by hosts. For example, a web application that uses (an address used by the cluster), will also accept traffic on port 80 directed at each individual cluster node. By configuring Internet Information Services (IIS), you can ensure that the node will only respond to the traffic directed at the cluster address rather than at the node address.
When you discuss the principle of least privilege, remind the students that application administrators rarely need local Administrator privilege on host servers. You should ensure that application administrators have only the minimum permissions necessary to carry out application administration tasks, and that in many scenarios, application administrators do not need to be able to perform NLB cluster management tasks.

21. Considerations for Scaling NLB
9: Implementing Network Load Balancing
NLB clusters can have up to 32 nodes
Use DNS round robin to distribute traffic between NLB clusters
Explain to the students how they can use DNS round robin and NLB together to create geographically dispersed NLB clusters. Use the text example of a client addressing the cluster in Sydney and being directed to the Sydney-hosted NLB cluster versus the client in Brisbane who, depending on DNS round robin, will be directed to either the Sydney, Canberra, or Melbourne NLB clusters.
Client in Sydney
Client in Brisbane
Cluster in Sydney
Cluster in Canberra
Cluster in Melbourne
Netmask ordering
DNS round robin

22. Considerations for Upgrading NLB Clusters
9: Implementing Network Load Balancing
NLB clusters can run with different operating systems
Windows Server 2012 R2 NLB clusters can interoperate with:
Windows Server 2003 & Windows Server 2003 R2
Windows Server 2008 & Windows Server 2008 R2
Windows Server 2012
Piecemeal upgrade:
Add Windows Server 2012 R2 cluster nodes
Remove nodes running earlier operating systems
Upgrade clusters:
Remove node from NLB cluster
Upgrade to Windows Server 2012 R2
Rejoin node to NLB cluster
Explain to the students that in some situations, it will not be possible to upgrade the operating system of a cluster node. For example, if the server has an x86 version of Windows Server® 2008 installed, it will not be possible to upgrade it. In this situation, you should remove the node from the cluster manually, migrate the server to Windows Server 2012 R2, migrate the applications, and then join the migrated server to the NLB cluster.
Discuss with the students the types of scenarios where they would perform piecemeal upgrades as opposed to rolling upgrades.

23. Additional Resources & Next Steps
Instructor-Led Courses
20412C: Configuring Advanced Windows Server 2012 Services
Books
Exam Ref : Configuring Advanced Windows Server Services
Exams & Certifications
Exam : Configuring Advanced Windows Server Services