One of the main reasons to move your app into a Docker image

is to make it easy to share with others.

But you don't have to upload image files to Dropbox or publish them on a website.

Registries provide a standardized way to share Docker images,

kind of like Git repositories.

With a Docker registry, you can upload images and

your users can download them with just a few simple commands.

The docker login subcommand lets you connect to a docker registry.

By default, it'll connect to Docker Hub, a public registry that offers both free and

paid plans, kind of like GitHub does with git repos.

You'll be prompted to visit hub.docker.com to create an account

if you don't already have one.

I've already created an account so I'll use my username, And password to log in.

Let´s upload the mongodb image, that we created earlier.

We do that with the docker push sub-command.

We need to specify the name of the image we want to upload.

Mongodb.

When we hit enter,

Docker will try to upload the image to our repository named library/mongodb.

There is a problem though, we don't own the library repository and

don't have access.

We'll need to retag the image using a repository name that we do have access to.

Fortunately that's really easy.

An image can have many tags, we'll just add another tag to our existing image.

We can do that with the docker tag subcommand.

We provide the existing name for the image, mongodb, followed by a new tag.

Docker Hub requires that images start with the Docker Hub username, so

I'll use mine, dockern00b.

Followed by a slash and then the name I want to use for

this particular image, mongodb.

When we hit Enter, the new tag will be added to the existing image.

Now let's try uploading it, using the new tag,

docker push dockern00b/mongodb.

This time the upload will be successful and

our image will be stored on the docker registry.

With our image successfully uploaded, our users will be able to download and

launch it as long as they have docker installed.

If it's a public repository, they don't even need to be logged into docker hub.

You can pull images from a docker registry with the docker pull subcommand.

We need to provide the repository name that it was uploaded with,

dockern00b/mongodb.

Docker will connect to docker hub and download the image,

when the download is complete, the'll be able to run it with docker run.

As always for this image, They need to publish port 27017.

So we'll run Docker, run -p 27017

publish support 27017 and

end with the image name, dockernoob/mongodb.

So with the container running we can run the mongo command and

we'll be able to connect successfully.

Docker registries let you manage images, collaborate with co-workers,

or simply manage the images you use locally for side projects.

Docker is optimized for version control of images.

And wherever possible,

will avoid redownloading parts of images that it already has.

Now we've covered how to manage images and containers from the command line.

In the final stage, we'll build a Node.js app from scratch, build an image for

it, run it as a container, and test it.

And at the end of the course we'll recommend some next steps that will help

you simplify operations and development using docker.