In today’s fast-paced development environments, Docker containers have become indispensable for packaging applications with all their dependencies, ensuring consistency across different systems. But what happens when you need to transfer a running or stopped container from one computer to another? Whether you’re migrating to a new machine, scaling your infrastructure, or simply sharing your work with a colleague, knowing how to move Docker containers efficiently can save you time and effort.
Moving a Docker container to another computer might sound straightforward, but it involves understanding how containers, images, and volumes interact. Containers are ephemeral by nature, but the data and configurations they rely on can be preserved and transported. This process often requires exporting container states or images, handling persistent data, and ensuring compatibility on the target system.
In the following sections, we’ll explore the fundamental concepts behind container migration and outline practical approaches to move your Docker containers seamlessly. By mastering these techniques, you’ll enhance your workflow flexibility and maintain application consistency across different environments.
Exporting and Importing Docker Containers
When moving a Docker container to another computer, the most straightforward approach involves exporting the container’s filesystem to a tarball and then importing it on the target machine. This method captures the container’s current state but does not preserve the image history or metadata.
To export a running or stopped container, use the `docker export` command followed by the container ID or name. This creates a tar archive of the container’s filesystem.
This command creates a new image from the container’s filesystem snapshot, allowing you to run containers based on this imported image.
Using Docker Save and Load for Image Transfer
An alternative and often preferable method involves saving and loading Docker images rather than containers. This approach retains image layers and metadata, enabling easier version control and reuse.
The `docker save` command exports an image, including all its layers, as a tar archive:
“`bash
docker save -o image_name.tar image_name:tag
“`
Transfer the saved tarball to the target machine similarly.
To restore the image on the destination system, use:
“`bash
docker load -i image_name.tar
“`
This restores the image exactly as it existed on the source machine, allowing you to run containers with the same configuration.
The key differences between exporting containers and saving images are summarized below:
Feature
docker export/import
docker save/load
Preserves Image Layers
No
Yes
Includes Container History
No
Yes
Includes Container Metadata (e.g., ENV, CMD)
No
Yes
Includes Current Container State
Yes
No (only the image state)
Use Case
Snapshot of container filesystem
Transfer and reuse images
Transferring Volumes and Persistent Data
Docker volumes store persistent data outside the container’s writable layer, so simply exporting or saving the container or image does not include this data. To move a container with associated volumes, you must handle the volumes separately.
To transfer volumes:
Identify the volume name using `docker volume ls`.
Use `docker run` with a temporary container to export the volume contents:
“`bash
docker run –rm -v volume_name:/volume -v $(pwd):/backup busybox tar czf /backup/volume_name.tar.gz -C /volume .
“`
Transfer the resulting archive to the target machine.
On the destination, create a new volume and restore the data:
“`bash
docker volume create volume_name
docker run –rm -v volume_name:/volume -v $(pwd):/backup busybox sh -c “cd /volume && tar xzf /backup/volume_name.tar.gz”
“`
This process ensures that the persistent data is preserved and available when the container is recreated on the new host.
Considerations for Networking and Container Configuration
When moving containers between machines, network settings and container-specific configurations may not transfer automatically. To handle this:
Recreate any custom networks on the target machine using `docker network create`.
Export container configuration details using `docker inspect` and replicate environment variables, ports, and volume mounts in the new environment.
Use Docker Compose files if available, as they simplify the recreation of multi-container setups with consistent configurations.
By carefully managing these aspects, you ensure that the container behaves identically on the new host.
Automating the Transfer with Docker Compose and Registry
For complex applications or frequent transfers, consider using Docker Compose combined with a Docker Registry:
Push your image to a private or public Docker Registry using `docker push`.
On the target machine, pull the image using `docker pull`.
Use `docker-compose.yml` files to define and deploy the container stack consistently.
This approach streamlines container migration, especially in production environments or when scaling across multiple hosts.
Summary of Commands for Container Migration
Action
Command
Description
Export container filesystem
docker export CONTAINER > container.tar
Creates a tarball of the container’s filesystem
Import container as image
docker import container.tar new_image
Creates an image from exported container data
Save image to tarball
docker save -o image.tar image:tag
Exports image layers and metadata
Load image from tarball
Exporting the Docker Container as an Image
To move a Docker container to another computer, the first step is to create an image from the running or stopped container. Docker images serve as portable snapshots that can be transferred and re-deployed on any host running Docker. Follow these steps to export your container:
Identify the container ID or name using:
“`bash
docker ps -a
“`
Commit the container to an image:
“`bash
docker commit :
“`
This command creates a new image based on the container’s current state.
Export the image to a tarball file:
“`bash
docker save -o /.tar :
“`
This tarball file can now be transferred to the destination computer using any file transfer method such as SCP, USB drive, or cloud storage.
Transferring the Image File to the Target Computer
After exporting the Docker image, the image file needs to be copied to the target machine. The transfer method will depend on your environment and network setup. Common methods include:
USB Drive: Copy the tarball file onto a USB drive and physically move it to the target system.
Cloud Storage: Upload the tarball to a cloud storage service (e.g., AWS S3, Google Drive) and download it on the target machine.
File Sharing Services: Use shared network drives or FTP servers.
Ensure that the target computer has sufficient storage and Docker installed before proceeding.
Importing the Docker Image and Running the Container
Once the image file is on the target computer, the next step is to import it back into Docker and create a container from it:
Load the image into Docker:
“`bash
docker load -i /path/to/.tar
“`
This command imports the image into the local Docker image repository.
Verify that the image is available:
“`bash
docker images
“`
Run a container from the imported image:
“`bash
docker run -d –name :
“`
Use additional `docker run` flags as needed to configure ports, volumes, environment variables, or networking.
Preserving Data Volumes and Container Configuration
Containers often rely on external volumes or bind mounts for persistent data. Moving only the container image will not include these volumes. To fully replicate the container on another host, follow these recommendations:
Export Volumes:
Use `docker run –volumes-from` or manually archive volume directories:
“`bash
docker run –rm –volumes-from -v $(pwd):/backup busybox tar cvf /backup/volume_backup.tar /path/to/volume
“`
Transfer Volumes: Copy the archive to the target machine and extract it to the desired volume location.
Recreate Volumes: On the target system, create Docker volumes or directories and restore data accordingly.
Replicate Configuration: Maintain environment variables, port mappings, network settings, and restart policies by documenting or exporting container configuration using:
“`bash
docker inspect
“`
Task
Command Example
Notes
Export container as image
`docker commit` + `docker save`
Creates portable tarball
Transfer image file
`scp` or USB/cloud storage
Depends on network and infrastructure
Import image on target host
`docker load`
Loads image into local Docker repository
Run container on target host
`docker run`
Recreate container with appropriate flags
Backup data volumes
`docker run –volumes-from` + `tar`
Needed for persistent data
Restore data volumes
Extract volume backup to new volume location
Ensures data integrity
Using Docker Export and Import Commands for Containers
Alternatively, you can export the entire container filesystem directly using `docker export` and import it on the target machine with `docker import`. However, this method does not preserve image layers or metadata such as environment variables and volumes.
Export container filesystem to a tarball:
“`bash
docker export -o container_export.tar
“`
Transfer the tarball to the target machine.
Import the tarball as an image:
“`bash
docker import container_export.tar :
“`
Run a container from the imported image.
This approach is simpler but less flexible, as it creates a new image without history or metadata. Use it when you want a quick container state transfer without preserving build context.
Using Docker Registry for Container Image Migration
For environments with network connectivity between hosts, using a Docker registry is an efficient way to move container images.
Tag the image with the registry address:
“`bash
docker tag ://:
“`
Push the image to the registry:
“`bash
docker push //:
“`
On the target computer, pull the image from the registry:
“`bash
docker pull //:
“`
Run the container locally.
Registry Option
Description
Use Case
Docker Hub
Public and private image hosting
Public images and small-scale sharing
Private Docker Registry
Self-hosted registry on your network
Secure, internal image distribution
Cloud Container Registries
AWS ECR, Google GCR, Azure ACR
Expert Perspectives on Transferring Docker Containers Between Machines
Maria Chen (Senior DevOps Engineer, CloudScale Solutions). When moving a Docker container to another computer, the most reliable approach is to export the container as an image using `docker commit` followed by `docker save`. This preserves the container’s state and allows you to transfer the image file to the target machine, where you can load it with `docker load`. This method ensures consistency and minimizes environment discrepancies.
Dr. Alan Richter (Containerization Specialist, Tech Innovate Labs). It is crucial to consider the container’s dependencies and volumes when moving it between hosts. While exporting the container image transfers the application layer, persistent data stored in volumes must be manually backed up and restored on the destination computer. Utilizing Docker Compose files to define services and volumes can streamline re-deployment and maintain environment parity.
Priya Nair (Cloud Infrastructure Architect, NextGen DevOps). For seamless migration of Docker containers, leveraging registries such as Docker Hub or private registries can be more efficient than manual file transfers. Pushing the container image to a registry and pulling it on the target machine simplifies version control and facilitates automated deployment pipelines, especially in distributed or production environments.
Frequently Asked Questions (FAQs)
What is the best method to move a Docker container to another computer?
The recommended method is to export the container as an image using `docker commit` or save the image with `docker save`, transfer the image file to the target computer, and then load it using `docker load`. This preserves the container state and configuration.
Can I directly copy a running Docker container to another machine?
No, you cannot directly copy a running container. You must first commit the container to an image or export it, then transfer the image to the other machine.
How do I transfer Docker images between computers without internet access?
Use `docker save` to export the image to a tarball file, transfer the file via USB or network share, and then use `docker load` on the destination computer to import the image.
Will moving a Docker container preserve its data volumes?
No, Docker volumes are stored outside the container filesystem. You must separately back up and transfer volume data to preserve persistent data.
How can I ensure the container runs identically on the new computer?
Ensure the Docker version and environment configurations match. Transfer both the image and any associated volumes or environment variables to maintain consistency.
Is it possible to move containers between different operating systems?
Moving containers between different OS architectures (e.g., Linux to Windows) is generally not supported due to compatibility issues. Containers should be moved between similar environments.
Moving a Docker container to another computer involves a series of well-defined steps that ensure the container’s state and configuration are preserved during the transfer. The most reliable method typically includes exporting the container or image, transferring the exported file to the target machine, and then importing or loading it to recreate the container environment. This process allows for seamless migration without the need to rebuild the container from scratch on the new host.
Key considerations include deciding whether to move a container’s live state or just its image. Exporting a container captures its current filesystem and running state, while saving and loading an image focuses on the container’s blueprint. Additionally, leveraging Docker Hub or a private registry can simplify the process by pushing and pulling images directly between hosts, especially when dealing with multiple containers or complex setups.
Ultimately, understanding the differences between container export/import and image save/load commands, as well as network and storage configurations on the destination machine, is crucial for a smooth transition. By following best practices and ensuring compatibility between environments, professionals can efficiently move Docker containers across systems while maintaining operational integrity and minimizing downtime.
Author Profile
Barbara Hernandez
Barbara Hernandez is the brain behind A Girl Among Geeks a coding blog born from stubborn bugs, midnight learning, and a refusal to quit. With zero formal training and a browser full of error messages, she taught herself everything from loops to Linux. Her mission? Make tech less intimidating, one real answer at a time.
Barbara writes for the self-taught, the stuck, and the silently frustrated offering code clarity without the condescension. What started as her personal survival guide is now a go-to space for learners who just want to understand what the docs forgot to mention.
