ContainersVirtual machines
IsolationShare the host's OS kernelEach runs a full operating system
SizeMegabytesGigabytes
Start-upSeconds or lessMinutes
DensityMany per serverFewer per server
Best forMicroservices and CI/CDStrong isolation, different OSes, legacy apps
In practice
In the cloud, your containers usually run inside VMs, so you'll use both.
Where you'll see them
Docker and Kubernetes for containers; VMware, AWS EC2 and other cloud VMs for virtual machines.
Why it matters for your career
Every cloud and DevOps role works with both. Understanding the trade-offs helps you choose the right platform for each app.
