What is the primary characteristic of virtual machines in a cloud environment?

In a cloud environment, the primary characteristic of virtual machines is their ability to run on different physical hosts. This capability is a fundamental aspect of cloud computing, which enables flexibility, efficiency, and scalability. Virtual machines (VMs) abstract the underlying hardware, allowing multiple VMs to share physical resources like CPU, memory, and storage across various physical servers. This architecture allows VMs to be dynamically moved between hosts or allocated according to demand, which is essential for load balancing and resource optimization in cloud services.

By enabling VMs to operate on different physical hosts, cloud providers can ensure high availability and redundancy. If one physical machine fails, the VMs running on it can be quickly migrated or instantiated on other available machines without downtime for the applications and services they support. This characteristic is vital for business continuity and disaster recovery in cloud environments, making it a key advantage of virtualization technology in the cloud.