cgroup_learn

## Cgroup for Memory limitations
-----------------------------

#Check the image list, speciallly tomcat image should be there
docker images

# create a tomcat container 
docker run -d --name test1 tomcat

# See the docker stat help

# check the stat for tomcat container oberve the memory allocated, used
docker stats --no-stream test1


#Create new container using cgroup with limiting memory
docker run -d --name cgroupsm1 --memory 200m tomcat
docker container ls

# Observe the memory alloted, used for new tomcat container
docker stats --no-stream cgroupsm1

## CGROUP commands
systemd-cgls
systemd-cgls -l
systemd-cgls -a

# Top cgroup
 systemd-cgtop -t -n 1
 systemd-cgtop -t 

## CPU 

Know about your CPU number of cores, CPU MHz, CPU(s), Architecture, Core(s) per socket

lscpu
docker run -d --name cgroupsc1 --cpus 0.1 tomcat
docker run -d --name cgroupsc2 --cpus 0.3 tomcat

# Check CPU utilization for these 2 containers
docker stats --no-stream cgroupsc1 cgroupsc2
 
 # Modify the cpu
 docker stats --no-stream cgroupsc1
docker update cgroupsc1 --cpus 0.2
docker stats --no-stream cgroupsc1

## Create containers with cpuset

# Low priority
docker run -d --name lowpri --cpuset-cpus=0 --cpu-shares=20 busybox md5sum /dev/urandom 

#Observer CPU%
 docker stats --no-stream  lowpri

# High priority
docker run -d --name hipri --cpuset-cpus=0 --cpu-shares=80 busybox md5sum /dev/urandom 
docker stats --no-stream  hipri
docker stats --no-stream  hipri lowpri

Check the priorities of process  now 
top 

# cleanup containers 
docker rm -f -v lowpri hipri
 docker rm -f -v lowpri hipri