Module 10: Implementing Network Load Balancing

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An NLB cluster supports up to _ nodes.

DNS round robin

An alternative to building single NLB clusters is to build multiple NLB clusters and use _ to share traffic between them. this is a technology that allows a DNS server to provide requesting clients with different IP addresses to the same hostname, in sequential order.

multiple hosts

Configuration options for NLB: Affinity settings only apply when you use the _ filtering mode.

None

Configuration options for NLB: In this affinity mode, any cluster node responds to any client request, even if the client is reconnecting after an interruption. This affinity mode is suitable for STATELESS applications.

Network

Configuration options for NLB: When you set this affinity mode, a single node will respond to all requests from a class C network (one that uses the 255.255.255.0 subnet mask). This mode is useful for STATEFUL applications where the client is accessing the NLB cluster through load-balanced proxy servers.

Single

Configuration options for NLB: When you use this affinity mode, a single cluster node manages all requests from a single client. For example, if the third node in a cluster manages a client's first request, then all subsequent requests are also managed by that node. This affinity mode is useful for STATEFUL applications.

using multiple network adapters.

You can configure each host as part of multiple NLB clusters when _

-None -Single -Network

You can select from the following affinity modes in the Add/Edit Port Rule dialog box:

Single affinity would be appropriate in an e-commerce web application where it is necessary to ensure that a disconnected client reconnects to the same session.

Describe a situation where the single affinity setting would be appropriate.

Piecemeal upgrade

During this type of upgrade, you add new Windows Server 2016 nodes to an existing cluster, and then remove the nodes that are running older versions of the Windows Server operating system. This type of upgrade is appropriate when the original hardware and operating system does not support a direct upgrade to Windows Server 2016. What upgrade strategy is this describing?

Rolling upgrade

During this type of upgrade, you upgrade one node in the cluster at a time. You do this by taking the node offline, performing the upgrade, and then rejoining the node back to the cluster. What upgrade strategy is this describing?

load weight handling priority

Each node in a cluster must have identical port rules. The exception to this is the _ (in multiple-hosts filter mode) and _ (in single-host filter mode). Otherwise, if the port rules are not identical, the cluster will not converge.

oStarted. (This value makes the host rejoin the NLB cluster automatically.) oSuspended. (This value pauses the host, and allows you to perform operations that require multiple reboots without triggering cluster convergence.) oStopped. (This value stops the node.)

Host parameters: Initial host state. You can use this parameter to specify the actions the NLB host will take after a reboot. There are three possible values:

A node is removed automatically from an NLB cluster if it misses five consecutive heartbeats

How does NLB detect failure of a node?

once every second

How often in NLB cluster do heartbeats transmit between nodes?

Node utilization

NLB balances traffic based on what?

Microsoft System Center Operations Manager.

NLB can only detect server failure; it cannot detect application failure. One way to manage this problem is to implement a monitoring solution such as _

Virtual

NLB hosts have a dedicated IP address and a _ IP address.

Unicast

Network considerations for NLB: -Mode suitable for NLB clusters that have multiple network adapters.

Multicast

Network considerations for NLB: -Mode suitable for NLB clusters that have single network adapters. -Network devices must support multicast MAC addresses

IGMP Multicast

Network considerations for NLB: -improves switch performance -Requires a network switch that supports this functionality.

35

The NetworkLoadBalancingClusters module contains _ NLB-related cmdlets

NLB cluster address

The _ is a virtual address that the hosts in the NLB cluster share.

get-command -module NetworkLoadBalancingClusters

To see the list of Windows PowerShell cmdlets for NLB, use the following command:

Add/Edit Port Rule

To specify how you want to distribute requests across nodes in the NLB cluster, you configure a filtering mode when creating a port rule. You can do this in the _ dialog box, which you use to configure one of the following filtering modes: -Multiple hosts -Single host -Disable this port range

True

TorF? Each node in an NLB cluster needs access to the same consistent application data.

True

TorF? Each node in an NLB cluster should have the same configuration.

True Ensure that you delegate permissions to users, only for tasks that they need to perform on the NLB node

TorF? Members of the local Administrators group on any single node can add and remove cluster nodes, even if they are not members of the local Administrators group on those nodes.

False. NLB can only detect server failure; it cannot detect application failure.

TorF? NLB can detect server failure AND application failure.

False

TorF? NLB is not failure-aware.

TRUE

TorF? When you use multiple network adapters in multicast mode, configure firewall rules that allow access to applications that are hosted on the cluster, but block access to other ports.

TRUE

TorF? When you use multiple network adapters in the unicast mode, configure different firewall rules for each network interface.

True

TorF? You can configure NLB to preference some nodes over others.

False They must be STATIC

TorF? You must configure IP addresses of servers that participate in an NLB cluster to be DHCP

True. When you are designing geographically-dispersed NLB clusters, you should instead choose to deploy an NLB cluster at each site, and then use Domain Name System (DNS) round robin to distribute traffic between sites.

TorF? You must ensure all hosts in NLB cluster are on the SAME tcp/ip subnet.

IIS shared configuration

Use _ to ensure that web application configuration is consistent across NLB nodes

CSVs

Use _ to host shared application and configuration data for NLB applications.

Add-NlbClusterPortRule

Use this cmdlet to add a new port rule.

Disable-NlbClusterPortRule

Use this cmdlet to disable an existing port rule.

Enable-NlbClusterPortRule

Use this cmdlet to enable a disabled port rule.

Set-NlbClusterPortRule

Use this cmdlet to modify the properties of an existing port rule.

Remove-NlbClusterPortRule

Use this cmdlet to remove an existing port rule.

Netmask ordering Round-robin DNS

What are two methods for scaling out NLB? Weighted random early detection (WRED) Demand-priority ordering Netmask ordering Round-robin DNS

Network Load Balancing

What does NLB stand for?

NLB is a scalable, high-availability feature that you can install on all editions of Windows Server 2016 to distribute network traffic across a set of servers, which balances the workload that each server must handle.

What is NLB?

Stop terminates all active connections immediately. Drainstop blocks new connections, but allows existing connections to complete normally.

What is the difference between a Stop and a Drainstop command?

Scaling

What is the process of increasing the capacity of an NLB cluster? For example, if you have a four-node NLB cluster, and each cluster node is used to the point where the cluster cannot manage more traffic, you can add additional nodes.

Initial host state

You can configure nodes to rejoin a cluster automatically, by configuring the _ setting on the node's properties by using the Network Load Balancing Manager

virtual local area networks (VLANs)

You can improve NLB cluster performance when you use unicast mode by using separate _ for cluster traffic and management traffic

You will configure the host priority. You also will set the rule to use the single-host filtering mode.

What steps would you take to ensure that LON-SVR1 always manages requests for web traffic on port 5678, given the port rules that were established by the end of this set of exercises?

Set- NlbClusterNodeDip

When configuring NLB, which PowerShell command can you use to configure the cluster node's dedicated management IP? Set-NlbClusterNode Set- NlbClusterVip Set- NlbClusterNodeDip Set- NlbClusterPortRule

You can use port rules to load balance different applications by using the same set of hosts. For example, you might want to load balance all incoming requests on port 80 across all the nodes in the cluster, and direct all incoming requests on port 5678 to a single host.

When would you want to use port rules other than the default port rule?

convergence

When you add, or remove a node from a cluster, a process known as _ occurs. it is the process where a new list of cluster members is created and the cluster members record the current configuration of the cluster. It can only occur if you configure each node with the same port rules.

Multiple hosts

When you configure this filtering mode, all NLB nodes respond according to the weight assigned to each node. Node weight is calculated automatically, based on the performance characteristics of the host. icreases availability AND scalability because you can increase capacity by adding nodes, and the cluster continues to function in the event of node failure.

Disable this port range

When you configure this filtering mode, all packets for this port range are dropped, automatically without being forwarded to any cluster nodes.

Single host

When you configure this filtering mode, the NLB cluster directs traffic to the node that is assigned the highest priority. increases availability but do not increase scalability.

Piecemeal upgrade Rolling upgrade

When you perform an NLB cluster upgrade, what are the 2 strategies you can use?

SSL certificate

When you secure websites that you make highly available by using NLB, you must ensure that each website has an _ that matches the website name. You set the host header of each node to point to the IP address of the NLB cluster.

Initial host state

Which of the following can you configure in NLB that allows nodes to rejoin a cluster automatically? ForceJoin Drainstop Initial host state AutoJoin

Multiple hosts Single host

Which two of the following are filter modes that you can use with NLB? Multiple hosts Single host White-listed ports Excluded ports

Unicast Multicast

Which two operation modes can you configure with NLB? Unicast Broadcast Multicast ICMP multicast

Cluster nodes can be addressed both indirectly through the NLB cluster, and directly by hosts. For example, a web application that uses the www.adatum.com address (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 respond only to the traffic that is directed at the cluster address rather than at the node address.

Why do you use both port rules and firewall rules when securing NLB?

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. In most scenarios, application administrators do not need to perform NLB cluster management tasks.

Why should you use the principle of least privilege when assigning permission to NLB servers?

NlbClusterNodeDip

Windows PowerShell NLB nouns: Use to configure the cluster node's dedicated management IP

NlbClusterNode

Windows PowerShell NLB nouns: Use to manage a cluster node

NlbCluster

Windows PowerShell NLB nouns: Use to manage the NLB cluster

NlbClusterVip

Windows PowerShell NLB nouns: Use to manage the NLB cluster's virtual IP

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Windows Server 2016 NLB clusters can have between 2 and _ nodes

Privileged Access Management

Windows Server 2016 includes the new PAM feature. What does PAM stand for?

Stateless

Would you use NLB with Stateful or Stateless applications?

cannot

You _ (can/cannot) configure an NLB cluster where there is a mixture of unicast and multicast adapters.

default host

You also can configure NLB to direct traffic to a specific host, called a _.

-Priority -Dedicated IP address -Subnet mask -Initial host state

You configure the host parameters for a host by clicking the host in the Network Load Balancing Manager console, and then from the Host menu, clicking Properties. You can configure the following host settings for each NLB node:

You must configure affinity settings to accomplish this.

You have an eight-node Windows NLB cluster that hosts a web application. You want to ensure that traffic from a client that uses the cluster remains with the same node throughout their session, but that traffic from separate clients distributes equitably across all nodes. Which option do you configure to accomplish this goal?

Nothing will happen because NLB only detects server failure and not the failure of a particular application. In addition, approximately every fourth request to the application from clients will not be served.

You have created a four-node Windows Server 2016 NLB cluster. The cluster hosts a website that is hosted on IIS. What happens to the cluster if you shut down the World Wide Web publishing service on one of the nodes?

to the cluster to the individual node

You should configure applications on each node to respond only to traffic that is addressed _, and to ignore application traffic that is addressed _

You must configure host headers for each site on each node. In addition, you must ensure that host header configuration is identical.

You want to host the www.contoso.com, www.adatum.com, and www.fabrikam.com websites on a four-node NLB cluster. The cluster IP address will be a public IP address, and each fully qualified domain name (FQDN) is mapped in DNS to the cluster's public IP address. What steps should you take on each node to ensure that traffic is directed to the appropriate site?

Privileged Access Management (PAM)

_ is based on the concepts of just-in-time (JIT) administration and just enough administration (JEA). When you implement it, users request permissions to perform administrative tasks on a server and are automatically granted the appropriate privileges for a temporary period, based on rules that might include additional authentication steps.