Skip to Content

A stick figure smiling

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!

browse more comics! get the zine!
read the transcript!

processes can use a lot of memory

process 1: I want 10 GB of memory
process 2: me too!
Linux: guys, I only have 16 GB total

a cgroup is a group of processes

every process in a container is in the same cgroup

cgroups have memory/CPU limits

Linux: you three get 500 MB of RAM to share, okay?

use too much memory:| get OOM (“out of memory”) killed

process: I want 1 GB of memory
Linux: NOPE your limit was 500 MB you die now!
process, dead: oh no

use too much CPU: get slowed down

process: I want to use ALL THE CPU!
Linux: you hit your quota for this 100ms period, you’ll have to wait

cgroups track memory & CPU usage

Linux: that cgroup is using 112.3 MB of memory right now

you can see it in /sys/fs/cgroup

Saturday Morning Comics!

Want another comic like this in your email every Saturday? Sign up here!

I'll send you one of my favourite comics from my archives every Saturday.
© Julia Evans 2021 | All rights reserved (see the FAQ for notes about licensing)