Question

How to copy a Docker image from one server to another without pushing it to a repository first?

Posted December 1, 2020 16.3k views
Linux BasicsUbuntuCentOSDebianDockerLinux Commands

In some cases, you might not want to push a Docker image over to Docker Hub or a private Docker repository.

Here is how you could transfer a Docker image from one server to another without pushing the image to an external Docker repository!

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In order to transfer a Docker image from one server to another, what you need to do is first export the image to a file, then copy that file over from your current server to the new one using scp or rsync and finally load the image to your new server. Here’s how to do that:

  • First SSH to your server where you’ve got your Docker image currently stored at and then run the following command to generate the tar file:
  • sudo docker save -o /home/sammy/your_image.tar your_image_name
  • This will create a tar file of your image and store it at the /home/sammy/your_image.tar folder. You can check the size of the file with the ls command:
  • ls -lah /home/sammy/your_image.tar
  • Once you have your Docker image ready, you need to copy it over using rsync, scp, or SFTP using Filezilla for example. My personal favorite is rsync. If you are not familiar with rsync, I strongly suggest going through this tutorial here on how to use rsync:

https://www.digitalocean.com/community/tutorials/how-to-use-rsync-to-sync-local-and-remote-directories

In case that you decide to use rsync as well, to copy the file over run the following command:

rsync -avz /home/sammy/your_image.tar username@remote_server_ip_address:destination_directory

Note: make sure to chagne the destination_directory, the username and the remote_server_ip_address with your actual details

  • Once you have your .tar file copied over to your new server, SSH to the new server and load the Docker image:
  • sudo docker load -i your_image.tar
  • Then, in order to check if this was successful, you can run docker images to see the list of the available images:
  • sudo docker images

Here is a quick video demo on how to do the above as well:

This is pretty much it! I hope that it helps!
Regards,
Bobby

by Justin Ellingwood
Rsync is a tool for intelligently syncing local and remote directories. In this article we will explore the basic usage of this utility to copy files from directory to directory and from system to system.