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Jaya chandrika reddy
Jaya chandrika reddy

Posted on • Updated on • Originally published at jayachandrika.com

Learn Docker basics quickly!

Article originally written at https://jayachandrika.com

In this Article lets explore :

Have you ever built an application but it doesn't run on all platforms? Or been sick of installing different dependencies and libraries for each service/component in the application? Dodged the whole nine yards just to deploy, scale and manage a simple application??

Then DOCKER is waiting for you!!!

Docker:What the hell is it?

Docker is a set of platform as a service products that uses OS-level virtualization to deliver software in packages called containers.

(Well. . .thats the GOOGLE definition for you! )

To wrap it up simply,it is just a BOX!

Imagine,

  1. A printer box, we insert a paper and get printed text or colors on it.

    So how is it working ? Perhaps all the colors and required material is already present in the printer.
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  2. Consider a car wash, car is sent in, many process like washing, cleaning etc happen and at the end we get a shiny clean car (or a less rusty one).

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So, docker is like a printer box or car wash setup in this instance, taking an input and giving an output basically.

It is basically a box with an application and its related dependencies, libraries etc inside it

But why docker?

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Imagine we are building a zoo, we toss all animals like monkeys, Lion and Crocodiles in one big park with only one kind of food and only one kind of environment, lets say, land.

The bananas eaten by monkeys canโ€™t be used by Lions and crocodiles, the meat for Lions canโ€™t be eaten by monkeys. Monkeys want trees and crocodiles need a water space in the environment.

In similar way, if we are building an application that has services like a database and framework etc, The libraries and dependencies(food) used by databases (cassandra, postgresql, mongodb etc) may not be compatible/suitable for frameworks (strapi, nodejs express etc).

Eg: MongoDb version 4.26 might not be compatible/suitable for NodeJs version 4.16.4

To make it easy to develop, run and maintain an application and to operate on all the platforms we came up docker. The problem in zoo example can be solved by providing each animal, a separate boundary with the required food and environment.

Containers

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In docker we have those separate boundaries called containers. We place each service in one container with all the libraries and dependencies required for it.

Container is a completely isolated environment with their own processes, network interfaces and their own mounts.

Wait, doesnt it look familiar? Yes,you are right if you guessed it, they remind us of Virtual machines. If its similar to VMs, Why on Earth do we need to use Containers??

Well, Each VM has a separate OS along with libraries, dependencies and application, which increases overload and utilization, making it difficult to operate it in small PCs(though we might not use it there).

Whereas Containers share the same OS, considerably less overload and utilization than VMs. Hence they are just the darlings preferred for application development, deployment and management.

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Images

These are readymade templates of services like MongoDb, NodeJs etc, to run in containers. We can either use existing images from docker.io or create our own.

Creating an Image of the service helps in shipping it for deployments. Then it is just running a simple command to get the server up and running. We dont have to worry about creating environment, installing dependencies and what not.

Magic commands

Its time to blow some fairy pixel dust and do some magic!

Lets start with running an image in a container,using run command.

Run redis image in container

docker run redis

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List the version details

docker version

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List the Running containers

docker ps

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List the Running & Not Running containers

docker ps -a

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Remove a container

docker rm [container ID]

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Note: To remove a container make sure it is stopped first using stop command.

List the images

docker images

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Remove an image

docker rmi [image_name]

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Just download the image but not run in the container

docker pull [image_name]

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Thank you so much for reading my content. More of such content coming on this blog, so stay tuned.

Article originally written at https://jayachandrika.com

Top comments (49)

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stamper profile image
Alexander Toropov

docker stop 6f
can I identify container just by first two symbols???

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chandrika56 profile image
Jaya chandrika reddy • Edited

Very good question.As long as any other container doesn't start with 6f, you can use 6f. Suppose container A has id '6fedstk' and B has id '6fesyiu', you have to choose atleast 6fed to represent A, to make them distinguished

Hope it was clear. Do ask for more doubts๐Ÿ˜„

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stamper profile image
Alexander Toropov • Edited

it doesn't work for me :(

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chandrika56 profile image
Jaya chandrika reddy

May i know the container id names and the command you used?

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stamper profile image
Alexander Toropov

yes, sure ibb.co/pQXXgZX

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chandrika56 profile image
Jaya chandrika reddy

Try docker stop fdd

Let me know what happens

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chandrika56 profile image
Jaya chandrika reddy

Try docker stop fdd

Let me know what happens

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stamper profile image
Alexander Toropov

it seems that's my bad. I'm terribly sorry.
it doesn't work for the whole container ID as well
those containers just were not started
I thought the error message will be slightly different, like 'the container is not started yet'

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chandrika56 profile image
Jaya chandrika reddy

Glad you found the solution ๐Ÿ˜„

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stamper profile image
Alexander Toropov

here is the screenshot from console ibb.co/pQXXgZX

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developertharun profile image
Tharun Shiv

Didn't know that. Thanks for letting us know ma'am ๐Ÿ‘

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uma_bcc profile image
umamaheswari.v

Good one...

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uma_bcc profile image
umamaheswari.v

You can use the #devops tag to your post, it is very relevant to devops. ๐Ÿ™‚

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praveenreddy1798 profile image
praveenreddy1798

yeah

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developertharun profile image
Tharun Shiv

correct

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chandrika56 profile image
Jaya chandrika reddy

Thank you for the suggestion ๐Ÿ˜Š

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kashyapamit profile image
Amit kashyap

Nice

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chandrika56 profile image
Jaya chandrika reddy

Glad you found it useful ๐Ÿ˜„

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kashyapamit profile image
Amit kashyap

Well Iโ€™m just starting with Swift Server side, so yes you had the practical examples spot on!

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chandrika56 profile image
Jaya chandrika reddy

That's cool. Best of luck!

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dstri26 profile image
Trideep Barik

That's a beautiful post. Loved the way you created a relation between real life and dockerโœจ

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chandrika56 profile image
Jaya chandrika reddy

Very happy that it was interesting to you Mr.Trideep

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praveenreddy1798 profile image
praveenreddy1798

Helpful

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venkat121998 profile image
venkat anirudh

Docker seems interesting. good article btw

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chandrika56 profile image
Jaya chandrika reddy

Glad you enjoyed it Mr.Venkatโ˜บ๏ธ

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developertharun profile image
Tharun Shiv

Amazing article! Looking forward for more! Keep going.. ๐Ÿ™Œ

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chandrika56 profile image
Jaya chandrika reddy

Thank you for the support ๐Ÿ˜„

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jacksoft profile image
Jacksoft CS • Edited

Tha was very useful. Thanks for sharing

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chandrika56 profile image
Jaya chandrika reddy

Glad it was helpful to you ๐Ÿ˜Š

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yashraj021 profile image
Yash

Greatttttttt!!!!!

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chandrika56 profile image
Jaya chandrika reddy

Thank you โ˜บ๏ธ

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davidyaonz profile image
David Yao

Actually I use docker almost everyday but without knowing some of the facts you explained. Thanks for this great article.

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chandrika56 profile image
Jaya chandrika reddy

Glad you find it useful ๐Ÿ‘๐Ÿ˜Š

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