
Here's a preview from my zine, How Containers Work!! If you want to see more comics like this, sign up for my saturday comics newsletter or browse more comics!

read the transcript!
containers package EVERY dependency together
smiling stick figure with short curly hair: to make sure this program will run on your laptop, I’m going to send you every single file you need
a container image iS a tarball of a filesystem
Here’s what’s in a typical Rails app’s container: - your app’s code - libc + other system libraries - Ubuntu base OS - Ruby interpreter - Ruby gems
how images are built
- start with a base OS
- install program + dependencies
- configure it how you want
- make a tarball of the WHOLE FILESYSTEM
tiny stick figure with short curly hair: this is what docker build
does!
running an image
- download the tarball
- unpack it into a directory
- run a program and pretend that directory is its whole filesystem
images let you “install” programs realty easily
person, thinking: I can set up a Postgres test database in like 5 seconds! wow!
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