Azure Dedicated Host: the creation of virtual machines on a dedicated system

In Azure was recently announced the availability of the new service Azure Dedicated Host, that allows you to have a physical server in Azure, totally dedicated to your organization, on which to enable Windows or Linux virtual machines. This article describes what are the main features of the service, its benefits and what procedure to follow for activation.

Normally, without the adoption of this new service, in Azure physical hosts are used to host virtual machines of more tenants, and the isolation occurs through the multi-tenant hypervisor. Using Azure Dedicated Host, physical servers can keep running only the workloads of an individual tenant. In this way you can have a wider visibility and a higher control on the hardware on which are running the own virtual machines, with the certainty that the host are not shared with other customers of Azure.

Usage scenarios

The service Azure Dedicated Host can be very useful to meet the following usage scenarios:

  • Need to have an isolation at the host level for compliance reasons, in terms of physical security, data integrity and monitoring.
  • Have visibility and control over the server infrastructure on Azure hosting yours virtual machines. You can in fact define the type of host hardware, the characteristics of the processor and the number of cores, the type and size of the VMs that you plan to deploy, with the ability to choose different sizes for virtual machines, while maintaining the same series selected for the specific host.
  • Govern all maintenance activities at the host level given by the Azure platform, such as physical host operating system updates. By using theAzure Dedicated Host you have the option of choosing the most appropriate time of maintenance, within a maintenance window of 35 days.

If you need to cope with one of the above scenarios, theAzure Dedicated Host is definitely a great option, but if you don't have specific needs you should use the classic methodology for deploying virtual machines Azure, as it has a greater level of flexibility.

Activation of the service

The deployment of a new Azure Dedicated Host requires the presence of a host group. To this group can be added more Host, that will be used to host the new virtual machine in Azure. Deploy Azure Dedicated Host can be done throughARM templateCLIPowerShell, and directly fromAzure Portal. This article shows the steps for creating the service directly from the Azure Portal.

Figure 1 - Starting the procedure of creation of a Host Group

During the Host Group creation process you are requested specific settings such as Availability zones (Optional) and the number of fault domain.

Figure 2 – Parameters required when creating a Host Group

When the Host Group is created you can start the process of setting upAzure Dedicated Host, that will be associated with a specific Host Group.

Figure 3 – Start the process of creating a Dedicated Host

Among the parameters required in the creation of a Dedicated Host there is the family of VMs, that will be hosted by the specific host, the host group membership, the number of Fault Domain and the ability to automatically substitute the host in case of any problems. In addition, it requests information necessary to obtain the benefits in terms of licensing, reported in the following paragraph.

Figure 4 – Parameters required when creating a Dedicated Host

Completed the process of setting up Azure Dedicated Host it's possible, during the creation of a virtual machine, host it on a specific system . An important consideration is that the region must be the same as the host and the size of the VM must belong to the VM Host Family configured during creation.

During the virtual machine creation process is present, in the section Host of the tab Advanced, the ability to select the host group and the Dedicated Host.

Figure 5 — Select the Host Group and the Host when creating the VM

Aspects related to licensing

Azure Dedicated Host lets get some advantages in terms of licensing, with the ability to take advantage of theAzure Hybrid Benefit. You can use the licenses available to Windows Server and SQL Servers covered by Software Assurance even in this scenario. In addition, customers who have Windows Server Datacenter licenses and Software Assurance may have fired an unlimited number of Windows Server virtual machines in the environment Azure Dedicated Host. Similarly, clients with SQL Server Enterprise Edition licenses and Software Assurance may use unlimited virtualization rights for SQL Server on their dedicated host in Azure. For other vendors like SUSE or RedHat Linux is allowed to use the licenses available with Azure Dedicated Host. In this case it is advisable to check with vendors specific licensing conditions.

With the introduction of this new service, Microsoft is updating accordingly the terms of use of licences in order to clarify the distinction between the on-premises/traditional outsourcing services and cloud services. To get more information about it you can see the Microsoft's official documentation.

Another important aspect to consider is that using the Azure Dedicated Host you can use the service of Extended Security Updates for Windows Server 2008/R2 and SQL Server 2008/R2.

Cost of service

The cost of Azure Dedicated Host is calculated at the host level and not on the basis of the number of virtual machines running on the host. Software licensing costs are calculated separately based on use of individual VMs. To obtain licensing savings you can take into consideration what is reported in the previous paragraph. This is a pay-as-you-go, no activation or termination fee. For more details please visit the official page of costs.

Conclusions

The service Azure Dedicated Host allows you to contemplate new usage scenarios of the Azure platform, and is able to address the needs of those customers who require host isolation, targeted to meet compliance and governance requirements. Very interesting also the possibility to achieve savings in licensing, by using Azure Hybrid Benefit. The advice is to consider using this service only if really necessary for your needs, otherwise you should use the classic method of deployment of virtual machines.