What is the purpose and use case of tagging a Docker image with a Docker Hub username before pushing it to Docker Hub?
This is how the docker push command knows where to push an image – it looks at the tag. See this page in the docker docs.
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My Question ?
Sir , as you said - This is how the docker push command knows “where to push an image.”
But we are already authenticating our machine with the particular docker hub ID/ Repo where we want to send the image .
Then what is the use of tagging the image with the user id , as here we can only push to that particular repo ?
Following is what i did to push an image:
Let us say that “Image:1.1” is a docker image created by me. And a container is running on this image.
Now i want to share this image and push the same to the docker hub, For this i have to follow the following steps:
vi app.py
vi Dockerfile
docker build -t image:V1 .
docker images
docker run -d --name Con1 -p 8000:8080 image:V1
docker ps -a
docker tag image:V1 deepakranjanmishra1983/image:V1
docker images
# The image image:V1 is tagged and when we run the docker images command it displays a image name preceded by the docker hub username
# Now we have to push this particular image, the one with the username, to the docker hub.
# But before that we have to authenticate our machine with that docker it where we want to push the image
# Login
docker login -u deepakranjanmishra1983
docker push deepakranjanmishra1983/image:V1
docker push deepakranjanmishra1983/image:V1
Hi @dpakmishra.1983,
Logging in just tells Docker who you are. Tagging the image is like giving it an address, it tells Docker exactly where to send it on Docker Hub. Even though you’re logged in, you might be pushing to a repo that’s owned by your team or company, not just your personal one. Without the right tag, Docker won’t know where to push the image.
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