Docker Image vs Container – Point Out The Differences
FREE Online Courses: Transform Your Career – Enroll for Free!
Today, we will see Docker Image vs Container. Moreover, while learning the difference of Docker Image and Container we will also see what is Docker Image and Docker Container.
So, let’s start Docker Image vs Container Tutorial.
Difference Between Docker Image and Container
i. What is Docker Image?
An inert, immutable, file that’s essentially a snapshot of a container is what we call a Docker image. Basically, Images are created with created from a Dockerfile with the docker build command. And further, they’ll produce a container when started with a run.
Moreover, in a Docker registry Images are stored like registry.hub.docker.com. Since they can become quite large, images are designed to compose of layers of other images, allowing a minimal amount of data to be sent while transferring images over the network.
Some Key points:
- In simple words, a collection of files + some metadata is what we call Image and these files form the root filesystem of a container.
- These images are made of layers, conceptually stacked on top of each other.
- And, each layer can add, change, as well as remove files.
- Moreover, images can share layers to optimize disk usage, transfer times, as well as memory usage.
- It is a read-only template which we use to create containers.
- Though, it can be built by you or other Docker users.
- Images Store in the Docker Hub or the local Registry.
- The first 12 characters are the IMAGE ID that is also a true identifier for an image.
- We can remove unused Docker images to clean up a Docker host.
ii. What is a Docker Container?
Generally, a runnable instance of an image is a Docker Container. By using the Docker API or CLI we can create, start, stop, move, or delete a container.
As an advantage, we can connect a container to one or more networks or we can attach storage to it, or also we can create a new image on the basis of its current state. Moreover, it consists of; a Docker image, an execution environment, a standard set of instructions.
Well, we can also understand in some other way, that is if an image is a class, then a container is an instance of a class, that is a runtime object.
Also, we can say Containers are somehow the reason that why you’re using Docker because they’re lightweight and portable encapsulations of an environment to run applications.
Some Key points:
By using the docker run command we can create the Containers from images and also it can list with the docker ps command.
Docker engine takes an image, adds the top writable layer and initializes various settings in order to create a container (network ports, container name, ID and resource limits).
- It is an Isolated application platform.
- They attain everything which we need to run our application.
- Somehow, based on images.
- The true identifier for the container is CONTAINER ID.
- Running containers can be view by docker ps and stopped containers can be view by docker ps -a.
- We can use NAMES to identify a started container via the –name flag.
- As same as Images, by removing unused Docker containers, we can clean up a Docker host.
Docker Image vs Container
1. An image is a read-only filesystem But a container an encapsulate set of processes which are running in a read-write copy of that filesystem.
2. Instead of regular copy copy-on-write use to optimize container boot time.
3. From a given image, Docker run starts a container.
4. The top writable layer is the major difference between a container and an image. Basically, all writes that add new or modify existing data to the container stores in this writable layer. And, while the container erases, that writable layer is also erased. But, that underlying image remains unchanged.
So, this was all in Docker Image vs Container. Hope you like our explanation.
Conclusion
Hence, in this Docker Image vs Container Tutorial, we have seen whole about Containers and Images in detail. Though, if any doubt occurs feel free to ask in the comment tab.
Your opinion matters
Please write your valuable feedback about DataFlair on Google
Leave it to KDE to F+++up a useful which allows a User to have separate Wallpaper with it’s own set of of “Widgets” for each Virtual Desktop as was easily done in KDE 4.14.8 and has existed in some form or other since 4.6 getting better with each successive update. This is one of the most requested features of KDE. We have been stuck with this steaming pile of crap called KDE 5. In spite of requests of KDE to add back the a popular feature from KDE 4, KDE 5 REFUSES to do so. They are now at KDE 5.22.2 and they are constantly stamping out bugs in features few know how to use, and probably will never use, while REFUSING to add a very POPULAR feature that a lot of people not only USE but WANT.
I *THINK* I may have discovered — IN THEORY AT LEAST — a workaround and then I can give KDE a HUGE FINGER!! You ask KDE a question and they reply with a ton of jargon and technospeak. You would *think* that by NOW — at KDE 5.22.2 — there would be tons of Manuals, and YouTube videos out there so people could create custom desktops that work for them. Most of the YouTube videos are more reviews rather than step-by-step instructions on how to do something, and the few videos that are out there that show some feature is so rushed that it is gone in 3-4 seconds in a 5 minute video. As to manuals they are non existent. KDE 4 had the same problem that KDE 5 had but USERS screamed bloody hell at them, that by KDE 4.6 some slick videos and written instructions on HOW TO USE these features started to come out. We are at KDE 5.22.2 and USERS are SCREAMING AT THEM, and in spite of the screaming rather than ACT on what USERS WANT, they turn a deaf ear to USERS. This is OUTRAGEOUS!! I DESPISE KDE, the KDE 5 TEAM, and the KDE 5 Developers. Instead of BUILDING on the features in KDE 4.14 — the last version of KDE 4 that was released — they tore things down and started over from scratch. Results we now have a steaming pile of endless crap up to the current version of KDE 5 — 5.22.2 which they are still stomping bugs out of. When is ANYONE going to call for a FEATURE FREEZE, ADD BACK things that USER WANT, and start polishing the crap in there, and creating the MANUALS and YOU TUBE VIDEOS that show you HOW TO USE their crap? By NOW KDE 5 should be a highly refined GUI, with popular features carried over from KDE 4 part of it. The problem I have with KDE 5 — besides the overall sloppiness of it, and the utter lack of responsiveness to the wants and desires of USERS — is all the jargon they use.
In this case three terms that KDE uses that confuse me endlessly. are “Activities”, “Containers”, and now they throw in the new one, “Docker”. I *THINK* I know what a “CONTAINER” is — MAYBE!!! Since KDE 5 REFUSES to create something that I — and many other people — WANT — I have *MAYBE* created a simple workaround:
Step 1: Start with a BLANK WALLPAPER on KDE 5.XX.YY
Step 2: Select the number of VIRTUAL DESKTOPS the USER wants.
Step 3: (This is where I may go astray as I am guess at the usage of what is meant by a “CONTAINER”). CREATE A SINGLE GIANT “CONTAINER” that runs from top to bottom; side to side; and corner to corner. REPLICATE the CONTAINER foe EACH VIRTUAL DESKTOP.
Step 4: ADD a SEPARATE WALLPAPER/S or COLOR/S of the USERS choosing. Example: The USER has 6 Virtual Desktops (VD). Each VD has a SINGLE CONTAINER. EACH CONTAINER has its OWN WALLPAPER making it possible that there will be 6 DIFFERENT WALLPAPERS in use — one for EACH VD.
Step 5: ADD a PANEL to EACH CONTAINER (a total in this Example of 6)
Step 6: ADD any given set of WIDGETS to EACH VIRTUAL DESKTOP and CONTAINER COMBINATION.
Step7: USE this WORKAROUND in the same way as you would in KDE 4.
QUESTION: This SHOULD in THEORY work. The Fly in the Ointment is HOW do you start with the UNIFORM BLANK CANVAS onto which you CREATE and ADD the EMPTY “CONTAINER” which you then CUSTOMIZE with its OWN WALLPAPER and set of WIDGETS.?
QUESTION 2: HOW do you CREATE and ADD that LARGE EMPTY CONTAINER to the UNIFORM BLANK CANVAS.
For purposes here in case they are DIFFERENT from KDE’s MEANING, I am using a CONTAINER such as an EMPTY BOX — something you can fill with all manner of things and decorate anyway YOU WANT. No two BOXES will be alike since each will hold different contents. One BOX main contain BOOKS — SCIENCE. A SECOND BOX may contain BOOKS — FICTION. A THIRD BOX may contain KITCHEN WARE. Etc., etc., etc.
This, in theory, *should* work, but I do not have the knowledge if it WILL work, nor how one goes about A) creating the “container” B) if a “container” can be decorated with a Wallpaper.