Chapter 5. Containers: Micro OSes for Containers

Question 1

What makes minimal OSes for containers sensible?

Answer 1

• running applications in containers aims for light-weight environment for applications
• therefore it makes sense to eliminate all packages and services of the host OS, which are not essential for running containers

Question 2

What are Micro OSes for containers?

Answer 2

• Operating Systems with all packages removed, that are not essential to run the base OS and container-related services

Question 3

For what are Micro OSes used?

Answer 3

• as container OSes
• because they allow for fast container startups
• and provide lightweight container environment
• which is secure and easy to customize

Question 4

Name a few Examples for Micro OSes

Answer 4

• Alpine Linux
• Busybox
• Ubuntu Core
• VMware Photon OS
• Fedora Core OS
• k3OS

Question 5

How are Micro OSes adjusted to Container platforms/runtimes?

Answer 5

Several Micro OSes are optimized for certain platforms or distributions. Like:
k3OS -> Ranchers K3s lightweight Kubernetes Distribution

Additionally Micro OSes focus on certain aspects:
Ubuntu Core -> Security & reliablity

Question 6

How large are Micro OSes?

Answer 6

Can be from:
small - less than 10 mb
up to
large - around 800 mb