Since its launch a decade ago, Microsoft Azure has become a prominent player in the cloud services arena formerly solely dominated by Amazon Web Services (AWS). Microsoft has been able to leverage their presence amongst the enterprise space, offering a hybrid cloud strategy and providing mobility between in-cloud and on-prem workloads. The rise of Azure has been largely driven by Microsoft’s Enterprise Agreement (EA) contractual agreements, which enables enterprises to centralize their licensing management across departments, and to implement Azure within the organization and leverage its benefits.
When eying a migration to Azure, it’s important for enterprises to consider a few things. It’s important to consider which applications are being used within the organization, and how to plan and choose the tools which will be needed in the migration. Assessment of compatibility and the cost of using on-demand cloud resources to run applications are also important factors. Having an understanding of these elements will help to ensure a smooth and successful migration.
This article will address some of the challenges you may face in migrating a VMware environment to Azure. We will also discuss some best practices and solutions to help ensure a smooth migration.
VMware Migration Challenges
As you may expect, migrating large amounts of data to Azure from your on-premises environment can present some challenges. It requires sufficient bandwidth to replicate and transfer data. There is also the potential for downtime in your production VMs running day-to-day business operations. Add to that the dynamics of veteran enterprise IT environments – such as legacy installations in data center, including system interdependencies – and there is a lot to consider before embarking on this project.
It’s true these challenges are somewhat inevitable, though they’re not insurmountable. Virtualized Microsoft environments are all based on Hyper-V, making migration quite a bit easier due to this common thread. Azure also comes with a set of tools to apply to the migration of resource pools from both physical machines and VMware, through Azure Site Recovery (ASR).
Migrating with Microsoft ASR
ASR is the recommended method to migrate your virtual machines to Azure. ASR enables you to replicate your on-prem Hyper-V virtual machines, along with physical servers and VMware VMs, to Azure. This is also a useful tool for disaster recovery and performing failovers.
Amongst the benefits of using ASR is the pricing structure, which allows you to only pay for the resources you use, as you use them. Should you failover to Azure, the VMs are created with the replicated data. When you migrate from your on-prem environment to Azure, you can use your existing server CALs in Azure through the Azure Hybrid Use Benefit.
To use ASR, start by creating a new recovery vault. This recovery vault can be created through the Azure portal, by selecting ‘More Services’ and searching for ‘Recovery Services Vault’. From there, click ‘Add’ and provide the required information.
After you have created the recovery vault, you can begin to prepare the infrastructure. First, choose your protection goals, which is to replicate VMware machines to Azure.
he next step is to prepare the Configuration Server. This server is a Windows Server 2012 R2 which should be hosted on your on-premises VMware environment. The ‘Microsoft Azure Site Recovery Unified Setup’ needs to be downloaded and installed, as well as the vault registration key. The Configuration Server needs to have PowerCLI 6.0 installed.
Next, you’ll prepare the Configuration Server: a Windows Server which should be hosted on your VMware on-prem environment. Download and install the Microsoft Azure Site Recovery Unified Setup, along with the vault registration key. Your Config Server must have PowerCLI 6.0 installed.
Note: VMware also offers a capacity planning tool, which will help in estimating the amount of resources that will be used for the replication to the Config Server.
Once ‘Microsoft Azure Site Recovery Unified Setup’ is installed, a shortcut is created on the desktop called cspsconfigtool.exe. Run this tool to add an account and give ASR access to the VMware environment. See here for account permissions.
After setting up the source, the next step is the target environment, which includes the Azure subscription, deployment model, storage account for the data replication, and a dedicated virtual network.
Once you’ve set up the target, configure the replication settings:
In order to replicate a VMware machine to Azure, first install the Mobility Service. This service is used to capture data writes on the VM and to forward it on to the Configuration Server. The Mobility Service can be pushed either manually or automatically, depending on your preference. For a manual installation, the files are on the Config Server at <code>C:Program Files (x86)Microsoft Azure Site Recoveryhomesvsystemspushinstallsvcrepositor.</code>
Then, enable replication for the virtual machines. At this stage, you will select the previously prepared source environment, select the target environment (i.e. the storage account) to replicate the VMs, the destination VM, and the VM where the Mobility Service is installed.
After the replication of the virtual machine is complete, it will show up in Recovery Services vaults under the Replicated Items section, as “protected”. When a VM is protected, an unplanned failover is possible.
Depending on what account permissions you specified earlier, the VMware machine will be shut down, and Azure will create a vm from the replicated data in the storage account. Once the vm has successfully failed over, you can select ‘Complete Migration’, which will stop the replication of the source VM.
The virtual machine is now running independently in Azure. If you have an Azure Expressroute or an active site-to-site VPN (and provided you have migrated the VM to the virtual network associated with it), you can update your on-prem DNS settings to point to the new private IP within Azure, and connect to it. If the VM replicated successfully, you can then decommission the on-prem server.
Included in ASR is a failover automation feature called Recovery Plans. Recovery Plan enables you to define machine groups which need to be restored together (such as an N-tier application), and the order in which those systems failover and are brought online. The recovery plan can help you test and perform fixes to the migration plan. With replication enabled, the data will be copied into the ASR Vault. It also controls the order that the replicated machines and data are spun up into an Azure VM.
Additionally, the below diagram is a nice illustration of the recommended steps from Microsoft for migrating an on-prem application to Azure using ASR. This requires LRS or GRS (redundant) storage along with a Site Recovery Vault within your Azure account. Ensure they are both deployed in the same region. Then, you will need to create your network topology and perform migration tests using recovery plans.
For more information on the prerequisites and exact steps required to migrate using ASR, take a look at this detailed Azure documentation.
Over the last few years, the huge investments made in cloud infrastructure have enabled a new world of hosting options that make deploying a VM to the cloud more manageable than ever before. When migrating VMware to Azure, several migration paths and approaches can be considered, with each having its advantages and disadvantages.
Moving VMs to the Azure cloud provides enterprises with a huge range of scalability