How to Migrate Docker Volumes Between Servers: A DevOps Guide

Migrating a Docker volume between servers is a common task in cloud and DevOps environments, ensuring persistent container data is seamlessly transferred. This guide explains how to copy Docker volumes from one server to another using scp, a secure and efficient method for server migration.

Why Migrate Docker Volumes?

In DevOps and cloud computing, migrating a server along with its Docker volumes is crucial when:

• Upgrading infrastructure (e.g., moving to a more powerful server).

• Changing cloud providers (e.g., AWS to Azure).

• Creating backups of critical data.

• Scaling applications by replicating environments.

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Prerequisites for Docker Volume Migration

Before proceeding, ensure you have:
✔ Access to Both Servers:

• Old Server (Source): 34.225.255.81

• New Server (Destination)`
  ✔ SSH Key-Based Authentication:

• Public SSH key of the new server added to the authorized_keys file on the old server.
  ✔ Sudo Privileges:

• Required for accessing and copying /var/lib/docker/volumes/.

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Step-by-Step Guide to Copy Docker Volumes Between Servers

1. Generate SSH Key on the New Server (If Not Already Done)

Run this command on the new server:

ssh-keygen -t rsa -b 4096

This generates a key pair in ~/.ssh/id_rsa.

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2. Add SSH Key to the Old Server for Secure Access

Copy the public SSH key to the old server using:

ssh-copy-id azureuser@34.225.255.81

Alternatively, use:

cat ~/.ssh/id_rsa.pub | ssh azureuser@34.225.255.81 "mkdir -p ~/.ssh && cat >> ~/.ssh/authorized_keys"

This enables passwordless authentication, improving security and automation in DevOps workflows.

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3. Copy Docker Volume Using SCP

On the new server, run:

scp -r azureuser@34.225.255.81:/var/lib/docker/volumes/azureuser_mysql-data .

Explanation:

• scp -r: Recursively copies directories.

• azureuser@34.225.255.81:/var/lib/docker/volumes/azureuser_mysql-data: Source volume directory.

• . : Destination (current directory) on the new server.

To place it directly in /var/lib/docker/volumes/ on the new server, use:

scp -r azureuser@34.225.255.81:/var/lib/docker/volumes/azureuser_mysql-data /var/lib/docker/volumes/

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4. Set Correct Permissions on the New Server

After copying, update ownership and restart Docker to recognize the volume:

sudo chown -R root:docker /var/lib/docker/volumes/azureuser_mysql-data
sudo systemctl restart docker

This ensures the volume is accessible to containers in the DevOps pipeline.

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5. Verify the Migrated Docker Volume

List the Docker volumes on the new server:

docker volume ls

Run a container to check if the volume data is intact:

docker run --rm -v azureuser_mysql-data:/data busybox ls /data

If files are listed, the migration was successful.

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Conclusion

Migrating a Docker volume between servers is essential in DevOps, cloud computing, and infrastructure scaling. By leveraging scp and SSH key-based authentication, you can efficiently move persistent data between environments with minimal downtime.

For automated DevOps workflows, consider integrating Ansible or Terraform for seamless infrastructure migration. 🚀