Configuring IP Addresses and Dependencies for Multi-Subnet Clusters – Part III

First published on MSDN on Aug 31, 2011

Hi Fans,

This blog post will show the configuration of IP Addresses on multi-subnet clusters for the cluster's name, or “Client Access Point” (CAP).  This is different from the IP Addresses configuration for other clustered workloads as there is no way to add resource to the CAP via the GUI, it must be done using PowerShell (or Cluster.exe).

First, check out Part 1 of the series which showed configure IP Addresses for clustered workloads using the GUI. Part 2 covers some more advanced settings such as Possible Owners.  To see a video walkthrough of the multi-site deployment for this cluster, visit: http://technet.microsoft.com/en-us/edge/disaster-recovery-cluster-deployment-demo-multi-site-fa… .

In this scenario I have a 2-node cluster, DRCluster, and I have just added an additional two nodes at my second site.  If all four nodes were available when the cluster was created, the IP Addresses on both subnets for the CAP would have automatically been created.  However in this scenario the nodes in the second subnet were added later, so the new IP Address for the CAP must be manually created.

Overview

First let's take a look at the GUI for the ‘Core Cluster Resources' (CCR) which contains the CAP.  This can be done by selecting the cluster in the left navigation pane and expanding the ‘Core Cluster Resources' section.

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							Configuring IP Addresses and Dependencies for Multi-Subnet Clusters - Part III

Adding a new IP Address to the Group

To add a new IP Address to the CCR we must use PowerShell (or Cluster.exe).  We will launch PowerShell as an administrator and import the clustering module:

PS > Import-Module FailoverClusters

Next we will find the correct name of the CCR by running the cmdlet:

PS > Get-ClusterGroup

We see this is simply referred to as ‘Cluster Group':
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							Configuring IP Addresses and Dependencies for Multi-Subnet Clusters - Part III

Next we want to add a new IP Address which is a type of cluster resource.  Do not forget that PowerShell has great built-in help with examples, so even if you are not sure what the correct syntax is, you can use Get-Help -full to see all the details.  For just the examples, use Get-Help -examples.  This is very helpful in this case, giving the exact example we want to use:

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							Configuring IP Addresses and Dependencies for Multi-Subnet Clusters - Part III

To add an IP Address to the CCR we use the Add-ClusterResource cmdlet:

PS > Add-ClusterResource –Name NewIP –ResourceType “IP Address” –Group “Cluster Group”

We see that this was successful and the resource is in the Offline state:

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							Configuring IP Addresses and Dependencies for Multi-Subnet Clusters - Part III

This new IP Address is now visible in the GUI:

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							Configuring IP Addresses and Dependencies for Multi-Subnet Clusters - Part III

Configuring the New IP Address

To continue configuring this using PowerShell, you would use the Set-ClusterParameter cmdlet and Set-ClusterResourceDependency.  Once again you can use Get-Help to get additional guidance.  However that is not necessary as it is now possible for us to continue configuring the IP Address and set the dependencies from the GUI.

Right-click on the new IP Address and select ‘Properties'.  Under the ‘General' tab you are able to select the subnet that it is on (10.* for this scenario), as well as whether it uses DHCP or static IP Addresses:
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							Configuring IP Addresses and Dependencies for Multi-Subnet Clusters - Part III

After clicking ‘Apply' and exiting you will see that the IP Address remains offline.  If a static IP Address has been assigned it should be displayed.  If DHCP has been selected, then no IP Address will show.

To immediately request a DHCP IP Address, right-click on the IP Address and select ‘Bring this Resource Online'.  It will fail and an error message will be displayed.  This is expected since the CCR is not on that subnet, however it will grab the IP Address that it will want to use at this time.  Alternatively you can just wait until the first to the other subnet to get this IP Address.  In our case we have been given 10.121.27.199.

Configuring Dependencies

Finally we will make the CAP dependent on either of the two IP Addresses.  This will be a ‘OR' dependency because we want the CAP to be available so long as an IP address on either is available.

To do this, right-click on the CAP and select ‘Properties', then select the ‘Dependencies' tab.

Select the ‘Click here to add a dependency' text.

From the dropdown in the ‘AND/OR' column select ‘OR' since this will be an ‘OR' dependency type, then from the dropdown in the ‘Resource' column select the new IP Address:
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							Configuring IP Addresses and Dependencies for Multi-Subnet Clusters - Part III

Finally click Apply, and when you return to the Cluster Manager GUI you can see that it has been added to the CAP group:

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							Configuring IP Addresses and Dependencies for Multi-Subnet Clusters - Part III

It is in an offline state which is expected since the CAP is still on the 157.* subnet.

Testing Failover

We want to make sure that the new IP Address for the CAP will come online on the new cluster.  However in the GUI there is no way to move this resource group to another node (other than stopping the cluster service of the node it is currently on).

To do this in PowerShell we use the Move-ClusterGroup cmdlet and specify a node on the other subnet.

PS > Move-ClusterGroup “Cluster Group” –node DRCluster-2a

In the GUI you will now see that the CAP has changed subnets.  It is now online on the 10.* subnet and offline on the 157.* subnet:
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							Configuring IP Addresses and Dependencies for Multi-Subnet Clusters - Part III

This should help you understand successfully figure IP Addresses for the CAP in multi-subnet clusters.  Syntax for these operations using Cluster.exe is available here: http://technet.microsoft.com/en-us/library/cc736767(WS.10).aspx

Thanks!

Symon Perriman
Technical Evangelist

Private Cloud Technologies

Microsoft
@SymonPerriman

 

This article was originally published by Microsoft’s Failover Clustering Blog. You can find the original article here.