Restrict System Resource Usage with cgroups

vim /etc/systemd/system/my_limits.slice 

Description=my slice 
Before=slices.target 

[Slice]
CPUAccounting=true 
CPUQuota=50%
MemoryAccounting=true
MemoryLimit=500M

ESC 
:wq 
ENTER 

See more info at: http://man7.org/linux/man-pages/man5/systemd.resource-control.5.html

sudo systemctl daemon-reload 

This is when you will need to log into two extra terminals, so that you have three total. Two will be for interacting with two python containers, and one will be for monitoring the system resource usage.

In Terminal 1

[cloud_user@server1 ]$ sudo docker run -rm -it --cgroup-parent=my_limits.slice docker.io/python 

In Terminal 2

[cloud_user@server2 ]$ sudo docker run --rm -it --cgroup-parent=my_limits.slice docker.io/python 

In Terminal 3

[cloud_user@server3 ]$ htop

In each of the two python containers run this code:

import threading 

def test():
  while True:
    1000*1000

threading.Thread(target=test).start()
threading.Thread(target=test).start()
threading.Thread(target=test).start()
threading.Thread(target=test).start()
threading.Thread(target=test).start()

Monitor the results in Terminal 3, and you will see that the sum total resource usage of the containers will not exceed the given limits.