Cloud Witness in Windows Server vNext Technical Preview (2014-OCT)

No comments

In this blog post, we will look at configuring Cloud Witness, a new quorum option introduced in Windows Server vNext Technical Preview (OCT 2014 Release). Cloud witness was introduced as an option similar to a File Share Witness, but hosted on Azure without having to maintain any infrastructure within your datacenter. This allows us to have multi-site clusters without having the need to have a 3rd site as a witness.

Cloud Witness comes is useful in following scenarios

  • DR Multi-Site stretched Clusters without having a 3rd site
  • Clusters without shared Storage
  • Guest Clusters hosted in Azure VMs
  • Guest clusters hosted in Private Clouds

Since Cloud witness requires, internet connectivity, if there’s a Cluster with no internet connectivity, then we will not be able to leverage Cloud witness quorum configuration option.

Cloud witness uses REST APIs to interface with Azure Blob storage and it creates a single blob file per cluster. Because of this, hosting the cloud witness in Azure will only cost you less than a 1$ and the cost for hosting the witness file is negligible. Cloud Witness can be configured using PowerShell or using Failover Cluster Manager. In this, blog post I will demonstrate how we can configure Cloud Witness using Failover Cluster Manager.

Cloud Witness Architecture

clip_image001

Cloud Witness vs File Share Witness Comparison

clip_image002

Step by Step Configuring Cloud Witness

Let’s have a look how we can configure Cloud Witness

Step 01 – Open Failover Cluster Manager

clip_image003

Step 02 – Right click on Cluster Name -> More Actions and select “Configure Cluster Quorum Settings”

clip_image004

Step 03 – After selecting “Configure Cluster Quorum Settings”, this will launch wizard to configure Cloud Witness. Click Next

clip_image005

Step 04 – Select “Advanced Quorum Configuration” and then click next

clip_image006

Step 05 – unless you want to change voting configuration, click next and proceed to the next step

clip_image007

Step 06 – Select “Configure a cloud witness”

clip_image009

Step 07 – Next step requires us to obtain our Azure Storage Account details. Login Azure Management Portal https://manage.windowsazure.com and navigate to your Storage section.

clip_image010

Step 08 – Next select your Storage Account and click on “Management Access Keys”

clip_image011

Step 09 – Note down your Storage Account Name and also Primary Access Key. We need to provide these values when we configure Cloud Witness within Failover Cluster Manager.

clip_image012

Step 10 – Provide Storage Account name and also Storage Account key

clip_image013

Step 11 – Confirmation Window describing recent changes to Cluster Quorum configuration.

clip_image014

Step 12 – We have just completed configuring Cloud Witness. Navigate to your Cluster and under witness section you will notice that it’s now set to “Cloud Witness

clip_image015

We can also Cloud Witness resources added to Cluster Core Resources

clip_image016

You can also have a look at below screen recording, which also includes a Failover Test using Cloud Witness

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s