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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
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