Docker Volumes vs Bind Mounts: Choosing Storage, Backing Up Data, and Fixing Permission Errors

# Create a volume
docker volume create mydata

# List volumes
docker volume ls

# Inspect volume details
docker volume inspect mydata

# Mount a volume
docker run -d \
  -v mydata:/var/lib/postgresql/data \
  --name postgres \
  postgres:16

# Prune unused volumes
docker volume prune

# Basic bind mount
docker run -d \
  -v /host/path:/container/path \
  nginx

# Read-only mount
docker run -d \
  -v /etc/nginx/conf.d:/etc/nginx/conf.d:ro \
  nginx

# Mount the current directory (for development)
docker run -it \
  -v $(pwd):/app \
  -w /app \
  node:20 bash

docker run -d \
  --tmpfs /run:rw,noexec,nosuid,size=64m \
  --tmpfs /tmp \
  nginx

# Backup — extract the volume as a tar archive
docker run --rm \
  -v mydata:/data \
  -v $(pwd):/backup \
  alpine tar czf /backup/mydata-$(date +%Y%m%d).tar.gz -C /data .

# Restore
docker run --rm \
  -v mydata:/data \
  -v $(pwd):/backup \
  alpine tar xzf /backup/mydata-20250101.tar.gz -C /data

# Copy between volumes
docker run --rm \
  -v source_vol:/from \
  -v dest_vol:/to \
  alpine cp -a /from/. /to/

# Check UID inside the container
docker run --rm nginx id

# Match the host UID
docker run -d \
  --user 1000:1000 \
  -v $(pwd)/data:/app/data \
  myapp

# Set permissions in the Dockerfile
# RUN chown -R node:node /app
# USER node

version: '3.8'
services:
  db:
    image: postgres:16
    volumes:
      - pgdata:/var/lib/postgresql/data   # named volume
      - ./init.sql:/docker-entrypoint-initdb.d/init.sql:ro  # bind mount

  app:
    image: myapp
    volumes:
      - ./src:/app/src   # bind mount for development

volumes:
  pgdata:               # volume declaration
    driver: local