SQL Server 2012/2014

AlwaysOn Availability Group

Part 4 - WSFC Cluster Creation

v1.0 - 2014 - G.MONVILLE

Summary Part 4 - WSFC Cluster Creation ...................................................................................................................................... 2

WSFC Node Updates [Note] ...................................................................................................................................... 2

AlwaysOn - Prerequisites................................................................................................................................................. 3

Install Windows Features ............................................................................................................................................ 3

WSFC Cluster - Creation .................................................................................................................................................. 5

WSFC Cluster - Configuration ........................................................................................................................................ 8

Configure Networks ..................................................................................................................................................... 8

Configure Quorum........................................................................................................................................................ 9

Quorum Configuration Note ............................................................................................................................... 11

Guest Cluster Virtualization Configuration .......................................................................................................... 13

Hyper-V - Heartbeat configuration ................................................................................................................... 13

Hyper-V - Place SQL VM Nodes on Different Physical hosts ..................................................................... 14

Prestage - Availability Group Listener ....................................................................................................................... 15

Active Directory ........................................................................................................................................................... 15

DNS (Integrated in AD).............................................................................................................................................. 16

Part 4 - WSFC Cluster Creation

This part cover the configuration of the WSFC Cluster require for the AlwaysOn Availability Group.

WSFC Node Updates [Note]

In addition to WSUS update, you have to check Hotfix/Rollup for WSFC Cluster:

WS2012 R2

Recommended hotfixes and updates for Windows Server 2012 R2-based failover clusters:

http://support.microsoft.com/kb/2920151/en-us

Or on this article from the TechNet Blog “The troubleshooters and problem”

List of Failover Cluster related hotfixes post RTM for Windows Server 2012 R2 RTM

http://blogs.technet.com/b/yongrhee/archive/2014/02/16/list-of-failover-cluster-related-

hotfixes-post-rtm-for-windows-server-2012-r2-rtm.aspx

WS2012

Recommended hotfixes and updates for Windows Server 2012-based failover clusters

http://support.microsoft.com/kb/2784261

WS2008 R2 SP1

Recommended hotfixes and updates for Windows Server 2008 R2 SP1 Failover Clusters

http://support.microsoft.com/kb/2545685

AlwaysOn - Prerequisites

Install Windows Features

On all nodes install “.NET 3.5” and “Failover Clustering” features:

Add “Failover Clustering Administration Tools”:

Note: Only “Failover Cluster Module for PowerShell” is available on core node.

Or installation via PowerShell:

PowerShell

# For remote install add: -Computer <Hostname>

Install-WindowsFeature Net-Framework-Core -source V:\sources\sxs

Install-WindowsFeature Failover-Clustering -IncludeManagementTools # ‘-IncludeManagementTools’ includes: # * Failover Cluster Management Tools # * Failover Vluster Module for Windows PowerShell

WSFC Cluster - Creation

During the WSFC Cluster creation a CNO (Cluster Name Object) is created in Active Directory. This

operation requires specific AD right.

There are three options:

Give Active Directory right “Create Object” to the SQL Admin account which you plan to

create the WSFC Cluster.

Add temporarily the SQL Admin Account to the “Domain Admins” group (I use this for the lab)

Pre-stage the CNO before installation (see TechNet)

Prestage Cluster Computer Objects in Active Directory Domain Services:

http://technet.microsoft.com/en-us/library/dn466519.aspx

From M-SQLA1, launch “Failover Cluster Manager” console:

Launch “Validate Configuration”:

Add all SQL AlwaysOn nodes:

Do the Validation tests:

Check “Create the cluster now…”:

Enter Cluster name and add an IP (on the Public VLAN):

Note: Cluster Name and IP are used for management and Cluster operations. These resources are

known as “Cluster Core Resources”.

Create Cluster:

Check nodes status:

WSFC Cluster - Configuration

Configure Networks

Rename each Cluster Network and configure Communications allowed.

Network Communications

Public Cluster and Client

Heartbeat Cluster Only

Replication None

Configure Quorum

In this example I do not use a Witness. I use only the Dynamic Quorum mode (enabled by default).

Be careful, because Dynamic Quorum works fine as long as the nodes go down one by one. If

multiples nodes fail at the same time (e.g.: the loss of a datacenter), the Dynamic Quorum may have

malfunction (no recalculate vote). I will do further tests in a future article.

So for Production environment it’s recommended to use a Witness.

Configure Quorum:

NOTE Create WSFC Cluster through PowerShell

PowerShell

# Run "Validate Configuration and Open Report $clustreportPath = "D:\Reports\TestClusterReport_xxx-xx-xx" Test-Cluster -ReportName $clustreportPath Invoke-Item $clustreportPath # Create Cluster $ClustVIP = "10.0.1.25" $ClusterName = "CN=clustsqlao1,OU=Clusters,DC=lab1,DC=ad" write-host "Create Cluster: $($ClusterName)" New-Cluster -Name $ClusterName -StaticAddress $ClustVIP -NoStorage -Node "M-SQLA1" "M-SQLA2" "M-SQLA3" "M-, , ,SQLA4" #Check Cluster Creation $clust = Get-Cluster $null 2>if ($clust $null) { Write-Warning "Cluster not found" } -eqelse {Get-ClusterNode}

Quorum Configuration Note

Dynamic Quorum is a new feature came with Windows Server 2012.

When Dynamic Quorum is enabled (by default) , the cluster dynamically manages the vote

assignment to nodes, based on the state of each node. Votes are automatically removed from nodes

that leave active cluster membership, and a vote is automatically assigned when a node rejoins the

cluster.

Get the Quorum Type:

PowerShell

Get-ClusterQuorum fl * |

Check if Dynamic Quorum is enabled:

PowerShell

Get-Cluster ft name dynamic* -Autosize | ,

View the “Dynamic Node Weight” status for nodes:

PowerShell

Get-ClusterNode ft name *weight id state -Autosize | , , ,

Property Description

DynamicWeight This is the node weight manage by “Dynamic Quorum”. If a node is failed,

DynamicWeight = 0

NodeWeight This is the “hard” configuration, for example you can decided that nodes on a

DR site will not have a vote, so in this case NodeWeight = 0.

For more information about Quorum Configuration see TechNet Article:

Configure and Manage the Quorum in a Windows Server 2012 Failover Cluster

http://technet.microsoft.com/fr-fr/library/jj612870.aspx

NOTE Retrieve “NodeWeight” from SQL (Transact-SQL)

SELECT member_name, member_state_desc, number_of_quorum_votes FROM sys.dm_hadr_cluster_members;

Guest Cluster Virtualization Configuration

This part is for Hyper-V Hypervisor, I will add later configuration for VMware vSphere.

Hyper-V - Heartbeat configuration

On Hyper-V, during a Live Migration of a node, the Cluster resources (in our case the AAG) can

failover to another node. The configuration bellow is for tuning WSFC Cluster on a multi-site

environment or on a virtualized environment

What’s happen:

WSFC nodes send heartbeat packets to other nodes of the cluster. The default port for cluster

communication is TCP\UDP 3343.

If a node does not receive a response from another node for a specified period of time, the cluster

removes the node from cluster membership. By default, a cluster node is considered down if it does

not respond within 5 seconds. In this case another node will initiate failover

At the end of a Live Migration, the VM is stopped on the original Hyper-V host and begins to start on

the destination host. During this short time, the VM node may exceed the Heartbeat threshold and so

a failover starts. (Note: With the 2012 R2 version, “Live migration” has been improved. Migration is

faster and after several migration tests of SQL node the Availability Group have not failover).

To prevent this problem, you have to increase the Threshold (there are two parameters, one for

Cluster on same subnet, and one for cross-subnet):

Parameter Default Value Range Configuration needed

SameSubnetThreshold 5 heartbeats 5 <> 120 heartbeats 20 heartbeats

CrossSubnetThreshold 5 heartbeats 5 <> 120 heartbeats 20 heartbeats

Retrieve Cluster configuration

get-cluster | fl name, samesubnet*,crosssubnet*

Change values (in my lab same subnet):

(Get-Cluster).SameSubnetThreshold = 20

For information:

You can also configure Heartbeat Frequency.

By default, regardless of subnet configuration, heartbeat frequency is once every second (1000

milliseconds). So with the configuration above, we have 20 x 1000 = 20 seconds before node

becomes unavailable for the cluster (This is the Microsoft recommendation for Hyper-V).

Heartbeat frequency:

Parameter Default Value Range

SameSubnetDelay 1000 ms 250 <> 2000 ms

CrossSubnetDelay 1000 ms 250 <> 4000 ms

Hyper-V - Place SQL VM Nodes on Different Physical hosts

For guest clustering, if you have multiple Hyper-V hosts in cluster you have to host VM on different

physical hosts. To prevent that the VMs do not end up on the same host (during Live Migration or

PRO operation) you have to configure the Anti-Affinity rules on Hyper-V (AntiAffinityClassNames

Paramerter).

View Anti-Affinity Rules

Get-ClusterGroup | Select AntiAffinityClassNames

On the first Hyper-V Cluster:

$ColAntiAffinity = New-Object System.Collections.Specialized.StringCollection $ColAntiAffinity.Add("GuestClust-AlwaysOn") (Get-ClusterGroup -Name M-SQLA1).AntiAffinityClassNames = $ColAntiAffinity (Get-ClusterGroup -Name M-SQLA2).AntiAffinityClassNames = $ColAntiAffinity

Repeat the operation on the second Hyper-V Cluster for M-SQLA3 and M-SQLA4 nodes.

Prestage - Availability Group Listener

Active Directory

The Availability Group Listeners are register as Cluster Resources and so in Active Directory as VCO (Virtual Computer Object). As the CNO (Cluster Name Object), we have to prestage these VCO and give the appropriate permissions. With a Domain Admin account, launch the “Active Directory Users and Computers” console Click on the “View” menu and select “Advanced Features”. Go to the OU where there is the AlwaysOn cluster CNO, and create a new computer:

Enter the Listener name:

Edit Properties of the created VCO, add a description, go to the “Security” tab and add the AlwaysOn cluster CNO (here: clustsqlao1), under Permissions allow “Full Control“

Repeat operation for all Listeners:

DNS (Integrated in AD)

Launch the DNS console, go to you domain zone, and create an new Host (A or AAAA):

Enter the Listener Name and the IP Address:

Repeat the operation for all Listener :

Allow the Cluster Name Object (CNO) to update DNS records:

Note: This configuration must be done DNS is integrated to Active Directory.

Edit the properties of record created previously:

Go to the “Security” tab and add the CNO, give the Full Control permissions:

Repeat the operation on all Listeners DNS records.