Table of Contents

1. Challenge

   Create my_limits.slice in /etc/systemd/system/ and Set Resource Limits CPU on 50% Compute Capacity and RAM to 500M

   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

2. Challenge

   Reload the Daemon and Run Two Python Containers for Testing with --cgroup-parent=my_limits.slice Parameter

   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
   

3. Challenge

   Run a Stress Test in All of the Containers

   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.