Docker :2

DevOps Classroom Series – 17\Mar\2021

More about isolated areas

• Roughly isolated area is analogus to vm but major difference is VMs have a full blow os where as isolated areas (containers) dont have a full blow os.
• Since they dont have full blown os,
  • CPU and other resources are allocated to application rather than os
  • This reduces the overhead of OS Patching
  • Savings on cost as containers on license costs 
• Every container (isolate area) gets
  • CPU
  • RAM
  • Storage
  • Network (ip address)
• We will be using docker to create these isolated areas called as containers.
• Docker is british expression for Dock Worker who is responsible for loading and unloading container in the ship yard 

Intro to Linux Containers

• Modern container started in the Linux world and are product of immense contributions for over a period of time from organizations such as Google LLC
• Some of the major technologies in Linux which contributed to massive growth of containers are
  • kernel namespaces
  • control groups
  • union filesystems
  • Docker

Windows Containers

• Microsoft corp has worked along with Docker to bring container technologies to Windows Platform
• Windows Container can be created on
  • Window 10 (Non Home editions)
  • Windows Server 2016 and Later
• Microsoft had changed the core Window Kernel to implement Containers.

Docker Technology

• When we install docker, we have the following components installed into our machine
  • docker client
  • docker daemon (engine)
• Login into docker play ground create an instance and execute docker version  
• Lets try to create one container
  • from docker client we need to specify we need a container
  • lets use a simple image called as hello-world
• To run a docker container we need a docker image. Docker has hub which hosts lots of images  
• Now lets summarize the steps 
• Now lets try to create one more container with hello-world  
• So to create container we need images. In reality in container we would want to run our applications developed
• So we need to create images with our applications in it to create containers
• So the first task for us is to understand how to create images so that we can run our applications
• Terminology:
  • In case of Docker we will be packaging our applications as Docker images.