Containers and virtual machines (VMs) are both forms of virtualization that isolate workloads from computing resources, but they accomplish this in different ways.
At a high level, VMs virtualize underlying resources so that multiple operating system (OS) instances can run on the supporting hardware. VMs provide many benefits, including the ability to run different operating systems on the same server, whether it’s an on-premises server or cloud server. They also allow for more efficient and cost-effective utilization of physical resources and faster server provisioning. However, because each VM contains an OS image, libraries, applications, and other components, they can become large and difficult—and expensive—to move across environments.
Alternatively, a container virtualizes the underlying OS and causes the containerized app to perceive that it has the OS—including CPU, memory, file storage, and network connections—all to itself. Because the differences in underlying OS and infrastructure are abstracted, if the base image is consistent, the container can be deployed and run anywhere.
Containers are more portable and resource-efficient than virtual machines, but they’re constrained to the operating system they’re defined for. However, because containers share the host OS, they don’t need to start up an OS or load libraries. This enables them to be much more efficient and lightweight but less isolated. Containerized applications also reduce maintenance, such as patching and updates.
Containers and VMs can be used together. For example, organizations can run containers in VMs rather than directly on infrastructure, which takes advantage of VM isolation and security while boosting efficiency.
Get the Azure mobile app 
