Pushing our Image to a Container Registry
Once our container runs successfully, we can push it to a container registry so that others can pull the container. “Others” includes our Kubernetes cluster at UVA.
We have a few options for container registries. The two main options are DockerHub and GitHub Container Registry (ghcr.io).
For this workshop, we’re going to use GHCR. The main benefit of using GHCR over DockerHub is that it is less restrictive with how many times your image can be pulled in an hour.
Re-tagging our image
To use GHCR, we need to prepend our image name with ghcr.io/<github-username>. That means we will need to re-tag our image. We can do that with the docker tag command.
docker tag cagancayco/chickweight:latest ghcr.io/uvarc/chickweight
Allowing Docker to push to GHCR
If this is your first time using GHCR, it is likely that you need to authorize your local Docker installation to push to GitHub.
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Go to GitHub -> Settings -> Developer Settings -> Personal Access Tokens, or click here.
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Generate new token with read/write permissions for packages.
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Copy the token to the clipboard.
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In your terminal, run
docker login ghcr.io -u <github-username> -p <copied-token>
Now we can use docker push to push our container to GitHub!
docker push ghcr.io/uvarc/chickweight
Set the package to public
By default, GHCR packages (or images) are set to private. We need them to be public in order for the Kubernetes cluster to see it. To change the visibility, do the following:
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Go to Packages -> chickweight -> Package Settings
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Click “change visibility” and follow the on-screen instructions.