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4.4 Container Data Management

Managing data within Docker containers is essential for persisting changes, sharing data between containers, and ensuring data integrity. Understanding container data management is crucial for effectively working with Docker.

Data Persistence:

By default, Docker containers are ephemeral, meaning that any changes made inside a container are lost when the container is stopped or removed. To persist data, you can use Docker volumes or bind mounts.

Docker Volumes:

  • Docker volumes are a preferred method for managing persistent data within containers.
  • Volumes provide a way to store and share data between containers and between the host machine and containers.
  • You can create a volume using the docker volume create command. For example:
docker volume create volume-name
  • To use a volume, you can mount it to a specific path inside the container using the -v or --volume option with the docker run command. For example:
docker run -v volume-name:/container-path image-name
  • The data stored in a volume persists even if the container is stopped or removed.

Bind Mounts:

  • Bind mounts allow you to mount a directory from the host machine into a container.
  • With bind mounts, changes made inside the container are directly reflected in the host directory, and vice versa.
  • To use a bind mount, you can specify the host directory path and the container directory path using the -v or --volume option with the docker run command. For example:
docker run -v /host-path:/container-path image-name
  • Bind mounts provide a convenient way to work with existing directories on the host machine.

Data Sharing between Containers:

Docker volumes and bind mounts can be used to share data between containers. Multiple containers can mount the same volume, allowing them to access and modify shared data. This enables the creation of distributed and interconnected applications where multiple containers work together.

Data Integrity and Backup:

It's important to ensure the integrity and backup of container data. Regularly backing up volumes or the underlying directories used for bind mounts is crucial for data preservation. Docker also provides backup and restore mechanisms, as well as third-party tools, for managing container data backups.


In the upcoming chapter, we will delve into the world of Docker volumes and explore their significance in containerization. Docker volumes provide a way to persist and manage data within containers, allowing you to separate data from the container itself.

Understanding Docker volumes is crucial for building scalable and resilient applications, as it enables data sharing, data persistence, and seamless container upgrades. So, get ready to discover the power of Docker volumes and learn how to effectively manage data in your Docker containers.