Hands-on: Docker Storage Demystified
Are you ready to dive into the world of Docker storage solutions? Docker is known for its agility and efficiency, but understanding storage management can be a bit tricky. In this hands-on guide, we will walk you through each step, providing not just the “how” but also the “why” behind each action. Let’s explore the world of Docker storage together.
Step 1: Start the AWS EC2 instance running Docker
Before we dive into Docker storage, we need a platform to work on. We’ll start by launching an AWS EC2 instance configured for Docker usage. Amazon Web Services (AWS) provides a robust and flexible environment for running Docker containers.
Why? AWS offers scalability, security, and reliability, making it an excellent choice for Docker deployments.
After setting up the EC2 instance log on to it via ssh.
Step 2: Cleaning the Environment
Maintaining a clean Docker environment is crucial. We start by running:
docker system prune -a -f --volumesThis command cleans up unused containers, images, and volumes, saving disk space and reducing clutter in your Docker setup.
Why? Regular cleaning prevents resource wastage and ensures your system runs smoothly.
Step 3: Create a New Directory
Next, we create a dedicated directory for our Docker images. We run:
mkdir docker-volumes
cd docker-volumesHaving an organized structure makes it easier to manage and access your Docker images and configurations. Organizing your work ensures a clear and structured workflow.
Step 4: Download and Unzip Task Files
Now we fetch the task files we need. By running:
wget https://tcb-bootcamps.s3.amazonaws.com/tcb5001-devopscloud-bootcamp/v2/module5-docker/files/module5-docker.zip
sudo apt install unzip
unzip module5-docker.zip
cd handsontask/volumes
We download the necessary resources for our Docker project. These files contain configurations and code needed to build and run Docker containers.
Step 5: Build the Docker Image
Before building our image, let’s check the content of this directory housing files used to build our docker image.
It’s time to create our Docker image:
docker build . -t tcb-img-upload-file:v1.0
Building a Docker image is a fundamental step in containerization. You define your application and its dependencies in a Dockerfile, and this image can be used to launch containers consistently. Docker images encapsulate your application, ensuring portability and reproducibility.
Check your Docker images:
docker images
Step 6: Running a Container Without Data Persistence
We launch a container without data persistence using:
docker run --rm -d -p 8081:3000 --name ctr-upload-file tcb-img-upload-file:v1.0
This means that when the container is stopped, any data changes within it are lost. Sometimes, you need containers with no data persistence for temporary tasks or stateless applications.
List files in the container and upload directory:
docker exec <containerid> ls
ls uploads
Stop the container:
docker stop <containerid>Run the container again:
docker run --rm -d -p 8081:3000 --name ctr-upload-file tcb-img-upload-file:v1.0List files in the container and upload directory:
docker exec <containerid> ls
ls uploads
Step 7: Creating a Volume
We explore Docker volumes, a way to manage data persistence. We run:
docker volume ls
docker volume create upload-files
docker volume ls
sudo ls -l /var/lib/docker/volumes
sudo ls -l /var/lib/docker/volumes
Docker volumes offer a more robust way to handle data storage in containers, with various use cases. Volumes ensure data survives container destruction and allow the sharing of data between containers.
Stop the container:
docker stop <containerid>Step 8: Volume Persistence Managed by Docker
Run the container with a Docker volume:
docker run --rm -d -p 8081:3000 --name ctr-upload-file -v upload-files:/app/uploads tcb-img-upload-file:v1.0
docker inspect <containerid> | grep volume
This setup ensures data stored in the volume survives container restarts or replacements. Volume persistence is crucial for databases, file storage, and other stateful applications.
Upload a new file
we will access our application via the web browser on port 8081 and try a upload a file
List files in the container and upload directory:
docker exec <containerid> ls
ls uploadswe should see our uploaded docker file in the uploads volume of our containers.
Stop the container:
docker stop <containerid>Run the container with the Docker volume again:
docker run --rm -d -p 8081:3000 --name ctr-upload-file -v upload-files:/app/uploads tcb-img-upload-file:v1.0
This setup ensures data stored in the volume survives container restarts or replacements. Volume persistence is crucial for databases, file storage, and other stateful applications.
Step 9: Bind Mount — Folder/Directory Persistence Managed by You:
Stop the container:
docker stop <containerid>Create a backup directory and get the current path:
mkdir bkp-upload
pwdRun the container with a bind mount:
docker run --rm -d -p 8081:3000 --name ctr-upload-file -v /home/ubuntu/docker-volumes/handsontask/volumes/bkp-upload:/app/uploads tcb-img-upload-file:v1.0We use bind mounts, giving you control over directory persistence. Bind mounts are perfect for fine-grained control over data storage, especially when working with host-specific paths.
Step 10: Updating an Application File in Real Time without Building Image Process
Stop the container:
docker stop <containerid>Run the container with a bind mount to the templates directory:
docker run --rm -d -p 8081:3000 --name ctr-upload-file -v /home/ubuntu/docker-volumes/handsontask/volumes/templates:/app/templates tcb-img-upload-file:v1.0
We showcase real-time application file updates without rebuilding the Docker image. This demonstrates how Docker simplifies application maintenance and updates.
Navigated the fascinating world of Docker storage. From understanding basic cleaning practices to mastering data persistence with volumes and bind mounts, you’ve built a strong foundation for containerized applications. Docker’s versatility and scalability make it a fantastic choice for modern DevOps and cloud computing. Happy containerizing!
