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Does It Work?

Estimated time: 5 minutes

Before we start talking images, containers, and how we manage them — does this thing even work? How do we know?

Thankfully, Docker put together a simple image that helps us get our feet wet. 

docker run hello-world

Hello, old friend.

Let's see what that does.

And here we go.

So let's take this step-by-step.

  1. Do I have this image locally? If not, let's pull the tag latest from Docker Hub.
💡
When you don't specify a tag for hello-world, it implicitly assumes you want the latest version. If you want a specific tag, you can use docker run hello-world:linux to run the linux tag.
  1. Digest
    1. docker was built with security in mind. Once an image is pulled the SHA Digest of the local image is compared against the known SHA Digest on Docker Hub. Even the slightest change in the image would result in a mismatch.
  2. Status: Confirmation of the output of the command.

The rest of the output is from the hello-world image. The key takeaway?

IT WORKS !

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