Let’s Start With Docker

5 min readMay 10, 2021

Docker KeyNotes

Why Docker ?

Have you ever faced issues and various bugs due to version mismatch or libraries version issues ? If Not , then you might have faces the issues like , whenever you have tried some programs , code , APIs or any kind of coding in your local then it was running correctly but when you’ve shared with someone , check on other system or os , or deployed somewhere outside your environment , it had create issues or gave some bugs .

Also to solve those bugs or error you definitely used google searches or stack overflow as well.

Have you ever thought these searches and error fixing problem consumes your important time and instead of focus on your main concept you have lost your time in fixing those bugs .

What if , you’ll not have to worry about all those bugs or issues.

Here , comes the concept of “docker”

2) What is Docker ?

Docker is a set of platform as a service products that use OS-level virtualization to deliver software in packages called containers.
Docker is a tool designed to make it easier to create, deploy, and run applications by using containers
Docker is an open platform for developing, shipping, and running applications. Docker enables you to separate your applications from your infrastructure so you can deliver software quickly. With Docker, you can manage your infrastructure in the same ways you manage your applications.

3) Docker Client(CLI) & Server(Daemon)

4) What is Container ?

A Docker container image is a lightweight, standalone, executable package of software that includes everything needed to run an application: code, runtime, system tools, system libraries and settings.
From the name , “container” it can be easily understand that it contains something , and here in this case , docker container contains or allocated resources ( like- process , hard disk , memory , etc. which needs to run an appliation)

5 ) What is an Image or Image file ?

Image file contains the file system snapshot which is having ability to run the required application with the help of container ( which is having all the resources ).

Let’s understand with an example of a seed , having all the capability to become a tree but it cannot grow without resources like , water , soil , sunlight etc.

# Some Basics Commands For Docker

i) Installation in Ubuntu

Using Docker Engine

* sudo apt-get update

* sudo apt install docker.io

Using Conventional Scripts

* curl -fsSL https://get.docker.com -o get-docker.sh

* sudo sh get-docker.sh

ii) Getting Started

* docker run hello-world

It will check the image file locally , if not available then it will go to docker hub and then download it to local and also keep record in cache , so that if next time we will need , it will directly redirected from our cache.
When we execute “docker run” command , default command run and then exit.
docker run = docker create + docker start

* docker create hello-world

It will create a container and result a hash string, but it is not started yet.

* docker start -a <hash strng resulted after creation>

“-a” = attach to container and show the result

*docker ps

It shows the running container

* docker logs

It will show the logs of that container( what is running inside )

iii) Stop Docker

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*docker stop <container id>

Stop that specific container

* docker kill <container id>

It will forcly stop that container.
It give a sick kill messaged the process to close. It means stop write away.

iv) Running another command in a container

* docker exec -i -t <container id> <command>

e.g- docker exec -i -t c&5fdvhfd sh
“-i” : is a flag , which runs inside or stdin
“-t”: pretty formating
“sh” : is a command processor , like a terminal which start the terminal inside that container

6) Custom Operations