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Server virtualization is more than hardware consolidation. A well-built virtualized environment can be used to automate routine tasks. Although there is some effort involved in setting up this process, automation will usually save administrators a considerable amount of work in the long run. Automation also ensures that routine tasks are performed in a manner that is consistent with the organization's needs.
The most commonly automated task is VM creation. Products such as VMware's vCenter and Microsoft's System Center Virtual Machine Manager allow for template-based VM creation. Administrators are able to build VM templates that align with the organization's requirements and then use those templates for future VM creation. This ensures that new VMs are properly configured.
Some hypervisor vendors also allow for automated host provisioning. This process makes it possible to automatically install a hypervisor to a bare-metal host. Automated host provisioning can save a lot of time for large organizations that frequently bring new host servers online.
Automation is also commonly used for patch management. Typically, VMs are kept up to date via a patch-management system. For example, Windows VMs might be configured to receive patches from Windows Server Update Services. Patch management at the hypervisor level, however, needs to be handled differently because it often requires a disruptive reboot.
Automation can ease host-level patch management. Microsoft, for example, has a rolling update feature for clustered Hyper-V deployments. When a patch needs to be applied to an organization's host servers, the patch-management process performs a live migration of the VMs off of one host server. The host is then patched and rebooted, and the VMs are shifted back onto the host via live migration. The process is then repeated for the other hosts in the cluster. While it is possible to complete this process manually, doing so would be extremely tedious.
Hypervisor-level automation is not the best choice for every maintenance task. Storage provisioning, for one, might be better handled separately. Hypervisors such as ESX and Hyper-V can be configured to perform some storage-related tasks, but automation systems provided by the storage vendors are much more capable than those offered by hypervisor vendors.
Designing an automation strategy
FAQs on virtualization automation tools