In an example embodiment, a solution is provided that reduces downtime during operating system patching. This reduces the downtime, regardless of which activity is being performed, and is platform-agnostic. More specifically, a target image for the operating system is obtained. During a preparation phase, a virtual machine with the target image is deployed. This virtual machine is deemed a reference virtual machine. A backup of the reference virtual machine bootable root disk is then taken, and a reference root block device is updated with a customer virtual machine operating system/application/database configuration files and folders. These customer-specific configuration files are then copied from block devices of the customer virtual machine to the reference virtual machine. The reference virtual machine can then be powered on. Only then is the customer virtual machine shut down, and the reference virtual machine swapped in for the customer virtual machine, minimizing the downtime during this period.