containerization-and-devops
Class 5 - Docker Volumes and Bind Mounts (Hands-on)
Objective
- To understand Docker data persistence concepts
- To differentiate between Volumes and Bind Mounts
- To verify data persistence across container restarts
Environment Used
- Host OS: Windows 11
- Linux Environment: WSL (Ubuntu 24.04)
- Container Platform: Docker Engine
- Terminal: WSL Ubuntu
Experiment Execution with Screenshots
🔹 Step 1: Check Existing Docker Volumes
Initially verifies if any volumes exist.
docker volume ls
🔹 Step 2: Create a Named Volume
Creates a volume named testvol1 and verifies it.
docker volume create testvol1
docker volume ls
🔹 Step 3: Mount Volume to Container and Create File
Mounts the volume to /home/app and writes data.
docker run -it --rm -v testvol1:/home/app ubuntu /bin/bash
echo "sapid=500121882" >> /home/app/sapid.txt
cat /home/app/sapid.txt
exit
🔹 Step 4: Verify Data Persistence
Runs a new container and checks if file persists.
docker run -it --rm -v testvol1:/home/app ubuntu /bin/bash
cat /home/app/sapid.txt
🔹 Step 5: Bind Mount with Host Directory
Creates a host folder and mounts it to container.
docker run -it --rm -v $(pwd)/hostfolder:/data ubuntu /bin/bash
echo "Hello from bind mount" >> /data/test.txt
cat /data/test.txt
exit
🔹 Step 6: Verify Data on Host System
Checks file directly from host directory.
cat hostfolder/test.txt
🔹 Step 7: Create Another Named Volume
Creates volume myvolume.
docker volume create myvolume
docker volume ls
🔹 Step 8: Write Data into Named Volume
Mounts myvolume and writes data.
docker run -it --rm -v myvolume:/data ubuntu /bin/bash
echo "Hello from named volume" >> /data/file.txt
cat /data/file.txt
exit
🔹 Step 9: Verify Named Volume Persistence
Runs new container to confirm data persistence.
docker run -it --rm -v myvolume:/data ubuntu /bin/bash
cat /data/file.txt
Result
Docker volumes and bind mounts were successfully created and tested.
Data persisted across multiple container executions.
Learning Outcome
- Understood difference between Volumes and Bind Mounts
- Verified persistent storage in Docker
- Observed data sharing between container and host
- Learned practical data management techniques in Docker