Docker Cheatsheet

Volumes

Use this Docker reference while you build software engineering projects, review code for technical interview prep, or polish examples for a software engineer resume.

Volume Types

Type	Syntax	Use case
Named volume	`-v mydata:/app/data`	Managed by Docker; survive container removal
Bind mount	`-v /host/path:/ctr/path`	Dev: sync host source into container
Anonymous volume	`-v /app/data`	Throwaway; removed with `--rm`
tmpfs mount	`--tmpfs /run`	In-memory; not persisted, not shared

Named Volumes

docker volume create mydata             # create
docker volume ls                        # list
docker volume inspect mydata            # full metadata + mountpoint
docker volume rm mydata                 # remove (must not be in use)
docker volume prune                     # remove all unused volumes
docker volume prune --filter "label!=keep"

# Use in docker run
docker run -d -v mydata:/app/data postgres:17

Bind Mounts

# Absolute path required
docker run -d -v /home/user/app:/app node:22 npm start

# Current directory shorthand
docker run -it -v "$(pwd)":/app -w /app node:22 bash

# Read-only bind mount
docker run -v "$(pwd)/config":/etc/app/config:ro myapp

tmpfs Mounts

docker run --tmpfs /run:rw,noexec,nosuid,size=64m myapp

Compose Volume Syntax

services:
  db:
    image: postgres:17
    volumes:
      - pgdata:/var/lib/postgresql/data       # named volume
      - ./init.sql:/docker-entrypoint-initdb.d/init.sql:ro  # bind mount

  app:
    image: myapp
    volumes:
      - .:/app                                # dev bind mount
      - /app/node_modules                     # anonymous (exclude node_modules)

volumes:
  pgdata:                                     # Docker-managed named volume

  # External volume (created outside Compose)
  external_vol:
    external: true

  # NFS volume
  nfs_data:
    driver: local
    driver_opts:
      type: nfs
      o: addr=192.168.1.10,rw
      device: ":/exports/data"

Backup and Restore

# Backup a volume to a tar archive
docker run --rm \
  -v mydata:/data \
  -v "$(pwd)":/backup \
  alpine tar czf /backup/mydata.tar.gz -C /data .

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

Inspecting Volume Contents

# Spin up a throwaway container to browse
docker run --rm -it -v mydata:/data alpine sh

# Or copy out a file
docker run --rm -v mydata:/data alpine cat /data/file.txt

Volume Drivers

# AWS EFS (via rexray or native plugin)
docker volume create \
  --driver rexray/efs \
  --opt size=10 \
  efsvolume

docker plugin install rexray/s3fs S3FS_REGION=us-east-1

For production stateful workloads, prefer named volumes over bind mounts — they are portable across host paths and manageable via docker volume commands.