Docker volume is an essential feature to manage data in containerized applications. It is a powerful orchestration tool designed for simplifying managing and deploying multi-container applications using Docker. One of the most critical aspects is managing persistent data using volumes. This blog will reveal the importance of volumes in Docker Compose for data persistence and give you a practice guide to effectively use them.
What are Docker Volumes?
Docker volumes play a critical role in managing persistent data for containerized applications. Unlike temporary containers, docker volumes ensure that the critical data remains intact even when the container is updated or removed.
Portability is one of the key advantages of volumes over bind mounts and it can be moved easily between different hosts or containers. On the other hand, bind mounts are tied to a fixed location on the host system. In addition to that volumes support various storage drivers. Its let organizations to pick the most suitable storage solution for their needs which improves scalability, efficiency and data management in containerized environments.
Different Types of Docker Volumes
Docker volumes is a great way to help store and manage data outside the file system of a container. They act as separate storage spaces that containers can access. This makes it easier to keep your data even if a container stops, restarts or even gets deleted. Volumes also let multiple containers to share the same data.
On the basis of how you want to store and share data, you can choose the right docker volume.
Here are the main types of volumes:
- Anonymous Volumes: Anonymous volumes are temporary storage places that are automatically created without any name. During a container’s run, these are used mainly for short-term data.
- Named Volumes: These come with specific names and are separately managed. Named volumes allow several containers to share data. It is best for long-term storage, especially in production.
Other Types of Volumes:
- Host Volumes: These are directly stored on the host machine where Docker runs.
- Remote Volumes: These volumes are stored on a remote server which makes it possible for sharing data across different Docker hosts.
- Third-Party Volume Plugins: These plugins connect Docker to external storage like cloud services or distributed file systems.
It is crucial to pick the right volume type to make sure data is stored, shared, and managed properly on the basis of your needs.
Docker CLI Commands for Managing Volumes
- Docker has various commands that help in managing volumes:Docker volume ls – All volumes are showed on the host machine
- Docker run -v – Attaches file or a host directory to container
- Docker volume crea – Creates a new name volume
Creating and Managing Docker VolumesCrete a named volume
- Create a Docker Volume (Implicitly)
The easiest way to create a volume is by using the docker run command with the -v (or –volume) flag:
[docker run -it –rm –name nginx -p 8080:80 -v demo-earthly:/usr/share/nginx/html nginx]
If the source (before the 🙂 is a name, Docker will check if the volume exists. If not, it creates one.
If the source is a path, Docker uses a bind mount. To confirm the volume exists, use:
[docker volume ls]
- Declare a Volume in a Dockerfile
Use the VOLUME command to define a volume inside a Dockerfile.
- Build and Run the Image
Whenever a new container starts, Docker creates an anonymous volume and copies the content of /usr/share/nginx/html into it.
- View and Manage Volumes
Use docker volume ls to list all available volumes. Use docker volume inspect demo-earthly to get details of a specific volume.
- Mount a Volume to a Container
When you start a container to attach a volume, use the -v or –volume option:
[Docker run -it-v demo-volume:/data uhuntu]
To mount a read-only volume:
[Docker run -it -v demo-volume:/data:ro ubuntu]
Try to write to the folder inside the container:
[Echo “test” > /data/test]
This command will fail as the volume is read-only (ro).
- Using the – – mount Option
Use – -mount as an alternative to -v. Docker creates it automatically if the volume doesn’t exist.
- Configuration Volumes with docker-compose
You can use docker-compose for automating it instead of managing volumes for multiple containers manually.
Conclusion
Docker volumes help store and manage data in containers. They keep data safe even when containers stop and make sharing data between containers easy. By learning how to create, use, and manage volumes, you can keep your data persistent, accessible, and secure. Whether you’re building a small app or running a large system, Docker volumes give you the flexibility and control needed to manage data smoothly.
About SpringPeople:
SpringPeople is world’s leading enterprise IT training & certification provider. Trusted by 750+ organizations across India, including most of the Fortune 500 companies and major IT services firms, SpringPeople is a premier enterprise IT training provider. Global technology leaders like SAP, AWS, Google Cloud, Microsoft, Oracle, and RedHat have chosen SpringPeople as their certified training partner in India.
With a team of 4500+ certified trainers, SpringPeople offers courses developed under its proprietary Unique Learning Framework, ensuring a remarkable 98.6% first-attempt pass rate. This unparalleled expertise, coupled with a vast instructor pool and structured learning approach, positions SpringPeople as the ideal partner for enhancing IT capabilities and driving organizational success.
