Review of Preview – Azure Dedicated Host

Azure dedicated host will enable you to run your organization’s Linux and Windows virtual machines on single-tenant physical servers. It helps you to provide with visibility and control to help address corporate compliance and regulatory requirements.

You can find the documentation from Microsoft here.

AWS had this feature available from some time now, it is good that Microsoft also catching up and closing the gap.

Benefits of Dedicated Hosts.

  • Azure Hybrid benefit to Azure Dedicated Hosts – Microsoft offers on-premise Windows
  • Host level isolation
  • Underlying hardware infrastructure
  • Processor brand, capabilities and more
  • Type and size of the Azure

With an Azure Dedicated Host, you can control all host-level platform maintenance initiated by Azure (e.g., host OS updates). An Azure Dedicated Host gives you the option to defer host maintenance operations and apply them within a defined maintenance window, 35 days. During this self-maintenance window, you can apply maintenance to your hosts at your convenience, thus gaining full control over the sequence and velocity of the maintenance process.

Consistent with other Azure services, customers will get free Extended Security Updates for Windows Server 2008/R2 and SQL Server 2008/R2 on Azure Dedicated Host. Learn more about how to prepare for SQL Server and Windows Server 2008 end of support.

Azure Dedicated Hosts allow you to use other existing software licenses, such as SUSE or RedHat Linux. Check with your vendors for detailed license terms.

Let’s take a look at my comments on the deployment.

dedihost1

 

Creating Host Group: We need to create a Host Group first. It is the key pre-requisites for creating the Dedicated Host. You can create many Host Groups. Host Group will define the region, availability zone and the fault domain where you need to place your Dedicated Hosts and VMs. You need to make sure that  you are selecting the right zone and number of fault domains in the Host Group. You can only to use those information in the dedicated host settings.

Steps to create the Host Group is available in the Azure documentation.

Creating a dedicated host in the Host Group created.  

Deploying a Dedicated Host was quick in fact, just 8 seconds. WOW, gone those days that we need to wait for months to get a server procured 😊.

Steps to create the Dedicated Host is available in the Azure documentation.

 

dedihost2

There are challenges with resource groups. All the resources should be in the same resource group starting from the Host Groups, Dedicated Hosts and VMs. Microsoft should bring the flexibility to use different resource group for each of this. At least, I could not use same RG for all the applications hosted in the dedicated hosts. It is a critical design constrains which must be resolved.

The host does not have a dependency on azure resources likes vNET or subnets as it is deployed in the Azure back end network.

Today, there are only DsV3 and Es3 VM size families available for the preview. You need to select which VM family you would like to use for dedicated host you deploy. The option to replace the host automatically on failure is available during the deployment. It is not clear whether this will add additional cost or not. However, I would like to have that selected for every dedicated host.

Provision the VM

You need to follow the normal procedure to provision a VM then select the Host Group and Dedicated Host from the Advanced option. The VM must be in the same RG as the Host Group is. If you do not select the right VM family and RG, you won’t be able to add it to a Dedicated Host.

It is nice to have an option to go to the host group and start provisioning the VM from there so that it should only be listing the available VM category.

Other points.

You may note that some of the below points when you think about move/removing the resources.

  • You cannot remove it from a host when it is powered on. After you Stop the VM, can you remove it from the host.
  • Even if you have a VM in stop state you cannot delete the dedicated host.
  • You cannot delete dedicated host when there is a VM in the host. However, you can delete entire resources by deleting the RG.
  • If you have removed a VM from the host, you can add to a matching host. However, today it must be in the same resource group.
  • It does not give an option to remove individual VMs, but we need to select all the VMs to remove it.
  • You can remove the VM from a dedicated host after powered off the VM. However, I could not remove one by one, but I had to select all the VMs in that group to remove. I guess this must be rectified with GA.
  • I think you can move an existing VM which is matching with VM family to new Dedicate Host after you move in to the same resource group. However, I have not tested the exact that scenario.

I do not see MS talking about the DR with Dedicated Host. Since this would be dealing with critical data so we need to have host level isolation for the DR as well.

Summary of the enhancement required.

  • Freedom in using the multiple RGs for the Dedicated Hosts and VMs created under one Host Group.
  • Option to remove one by one VM from the dedicate host.
  • Start the VM provisioning by selecting the Dedicated Host using portal.
  • Integrate it with ASR to have Dedicated Host level Disaster Recovery. Like you have an option to select a dedicated host for the protected VM to meet the compliance requirements.
  • Bringing dedicated host to RI would be a good improvement as well. All about RI can be found in my previous blog.

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