92 lines
3.7 KiB
Markdown
92 lines
3.7 KiB
Markdown
|
|
Now that we've built an image, let's share it! To share Docker images, you have to use a Docker
|
|
registry. The default registry is Docker Hub and is where all of the images we've used have come from.
|
|
|
|
## Create a Repo
|
|
|
|
To push an image, we first need to create a repo on Docker Hub.
|
|
|
|
1. Go to [Docker Hub](https://hub.docker.com) and log in if you need to.
|
|
|
|
1. Click the **Create Repository** button.
|
|
|
|
1. For the repo name, use `getting-started`. Make sure the Visibility is `Public`.
|
|
|
|
1. Click the **Create** button!
|
|
|
|
If you look on the right-side of the page, you'll see a section named **Docker commands**. This gives
|
|
an example command that you will need to run to push to this repo.
|
|
|
|
{: style=width:75% }
|
|
{: .text-center }
|
|
|
|
## Pushing our Image
|
|
|
|
1. In the command line, try running the push command you see on Docker Hub. Note that your command
|
|
will be using your namespace, not "docker".
|
|
|
|
```plaintext
|
|
$ docker push docker/getting-started
|
|
The push refers to repository [docker.io/docker/getting-started]
|
|
An image does not exist locally with the tag: docker/getting-started
|
|
```
|
|
|
|
Why did it fail? The push command was looking for an image named docker/getting-started, but
|
|
didn't find one. If you run `docker image ls`, you won't see one either.
|
|
|
|
To fix this, we need to "tag" our existing image we've built to give it another name.
|
|
|
|
1. Login to the Docker Hub using the command `docker login -u YOUR-USER-NAME`.
|
|
|
|
1. Use the `docker tag` command to give the `getting-started` image a new name. Be sure to swap out
|
|
`YOUR-USER-NAME` with your Docker ID.
|
|
|
|
```bash
|
|
docker tag getting-started YOUR-USER-NAME/getting-started
|
|
```
|
|
|
|
1. Now try your push command again. If you're copying the value from Docker Hub, you can drop the
|
|
`tagname` portion, as we didn't add a tag to the image name. If you don't specify a tag, Docker
|
|
will use a tag called `latest`.
|
|
|
|
```bash
|
|
docker push YOUR-USER-NAME/getting-started
|
|
```
|
|
|
|
## Running our Image on a New Instance
|
|
|
|
Now that our image has been built and pushed into a registry, let's try running our app on a brand
|
|
new instance that has never seen this container image! To do this, we will use Play with Docker.
|
|
|
|
1. Open your browser to [Play with Docker](http://play-with-docker.com).
|
|
|
|
1. Log in with your Docker Hub account.
|
|
|
|
1. Once you're logged in, click on the "+ ADD NEW INSTANCE" link in the left side bar. (If you don't see it, make your browser a little wider.) After a few seconds, a terminal window will be opened in your browser.
|
|
|
|
{: style=width:75% }
|
|
{: .text-center }
|
|
|
|
|
|
1. In the terminal, start your freshly pushed app.
|
|
|
|
```bash
|
|
docker run -dp 3000:3000 YOUR-USER-NAME/getting-started
|
|
```
|
|
|
|
You should see the image get pulled down and eventually start up!
|
|
|
|
1. Click on the 3000 badge when it comes up and you should see the app with your modifications! Hooray!
|
|
If the 3000 badge doesn't show up, you can click on the "Open Port" button and type in 3000.
|
|
|
|
## Recap
|
|
|
|
In this section, we learned how to share our images by pushing them to a registry. We then went to a
|
|
brand new instance and were able to run the freshly pushed image. This is quite common in CI pipelines,
|
|
where the pipeline will create the image and push it to a registry and then the production environment
|
|
can use the latest version of the image.
|
|
|
|
Now that we have that figured out, let's circle back around to what we noticed at the end of the last
|
|
section. As a reminder, we noticed that when we restarted the app, we lost all of our todo list items.
|
|
That's obviously not a great user experience, so let's learn how we can persist the data across
|
|
restarts! |