When you need to quickly and safely move virtual machines (VMs) from one site to another, the success of the transfer depends on many factors: team, timing, tools, and planning. And errors during the migration process can cause downtime, crashes, and other difficulties. And the more errors during the transfer, the more severe the consequences for the business.
We tell you how to prepare and carry out migration between platforms without pain and undesirable consequences, as well as show scenarios for migrating VMs between platforms for operating systems (OS) Linux and Windows.
When You Might Need a VM Migration
There can be many reasons for migrating a VM to a new solution. Here are the main ones:
- Scheduled server maintenance – when the VM must remain available even during the maintenance period;
- updating the IT infrastructure – to run virtual machines on more powerful and modern servers;
- Change of vendor – to move to a new site from a service provider, work with which is unsatisfactory or cannot be continued due to various reasons.
How To Prepare For a VM Migration
Attention when migrating virtual machines can lead to problems. The migration is carried out in several stages, using a universal scheme that will be relevant for moving from any platform.
Migration is impossible without careful study – you need a clear plan, which should reflect the following:
- the current state of the VM;
- parameters of the current site and the platform to which the transfer is planned;
- the sequence of migration;
- deadlines for the project as a whole and each stage separately;
- incident response options.
Planning is the biggest and most challenging stage. The consequences of mistakes here often become noticeable only after a few months, when eliminating them is much more difficult. Therefore, it is essential to foresee all the details.
Before migrating from platform to platform, you must install the missing components and check their settings following the requirements. Such preparation of scripts is necessary so that, for example, a virtual machine with VMware can work in OpenStack.
Upload the system image
The next step is to upload the virtual machine image from the current platform. Upload options can be different: they depend on the platform on which the VM is deployed.
When migrating virtual machines from VMware or other platforms, it is essential to download the image in VMDK format. But by default, this option is unavailable everywhere, so you may need an intermediate conversion using third-party tools.
The VMDK image is loaded onto the new virtualization platform.
The VM is running on a new platform. At the same time, network addresses will change when migrating virtual machines from Hyper V or any other. Before starting, you need to reconfigure DNS records and switch the load.
If at the time of the migration, the VM continues to work on the original platform after its launch on the new site, you need to reload the data delta. This information has accumulated during the migration.