CODEWITHSUNDEEP
dockerdocker-image
kmario23
kmario23

Reputation: 61365

what is a docker image? what is it trying to solve?

I understand that it is software shipped in some sort of binary format. In simple terms, what exactly is a docker-image? And what problem is it trying to solve? And how is it better than other distribution formats?

As a student, I don't completely get the picture of how it works and why so many companies are opting for it? Even many open source libraries are shipped as docker images.

Upvotes: 0

Views: 124

Answers (1)

Roman Kiselenko
Roman Kiselenko

Reputation: 44370

To understand the docker images, you should better understand the main element of the Docker mechanism the UnionFS.

Unionfs is a filesystem service for Linux, FreeBSD and NetBSD which implements a union mount for other file systems. It allows files and directories of separate file systems, known as branches, to be transparently overlaid, forming a single coherent file system.

The docker images сonsist of several layers(levels). Each layer is a write-protected filesystem, for every instruction in the Dockerfile created own layer, which has been placed over already created. Then the docker run or docker create is invoked, it make a layer on the top with write persmission(also it has doing a lot of other things). This approach to the distribution of containers is very good in my opinion.

Disclaimer: It is my opinion which I'm found somewhere, feel free to correct me if I'm wrong.

Upvotes: 1

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