images

Servers should be a commodity, not a special snowflake that needs attention. Images are snapshots that can be loaded onto a server, containing all the information needed to get to work instantly.

There are 2 types of images:

• hypervisors: are images that host containers. Generally stay alive for longer periods of time and should only start be in charge of managing containers.
• containers: are images that do one thing well. Generally they will be completely self-contained, requiring only a few ports to be open.

Containers themselves can be split up in 2 types:

• services: handle application logic. Whether it's handle HTTP requests, host a server or do crunch numbers, services take care of it all.
• sidekicks: handle secondary tasks such as log forwarding, sending health checks to the mothership and other secondary jobs.

AMI

AMI's are Amazon's custom image format.

Qemu

qemu is a command to build images for either xen or KVM.

KVM

KVM is a virtual machine that resides on the kernel level. It's as low level as you can get for virtual-machines. If you need Linux-based virtualization then KVM is the solution.

Packer

packer is a tool by hashicorp that can stamp out images for multiple compile targets based on a single configuration. Targets include: kvm, docker and AMI.