Docker Volume and Network Management: Persistent Storage and Network Configuration

Docker Volume and Network Management

Docker containers are ephemeral by default — when a container is deleted, its data is lost too. Volumes solve this problem and ensure data persists independently of the container lifecycle. Docker networks manage communication between containers and with the outside world.

Docker Volume Types

Type	Description	Use Case
Named Volume	Managed by Docker	Database, application data
Bind Mount	Mount host directory	Development, config files
tmpfs Mount	Memory-based temporary	Sensitive temporary data

Named Volume Management

hljs bash

# Create a volume
docker volume create myapp-data

# List volumes
docker volume ls

# Inspect volume details
docker volume inspect myapp-data

# Remove a volume
docker volume rm myapp-data

# Remove unused volumes
docker volume prune

# Remove all volumes (careful!)
docker volume prune -a

Running Containers with Named Volumes

hljs bash

# Run MySQL with volume
docker run -d \
  --name mysql-db \
  -e MYSQL_ROOT_PASSWORD=StrongPass123! \
  -e MYSQL_DATABASE=myapp \
  -v mysql-data:/var/lib/mysql \
  -p 3306:3306 \
  mysql:8.0

# Run PostgreSQL with volume
docker run -d \
  --name postgres-db \
  -e POSTGRES_PASSWORD=StrongPass123! \
  -e POSTGRES_DB=myapp \
  -v postgres-data:/var/lib/postgresql/data \
  -p 5432:5432 \
  postgres:15

Using Bind Mounts

hljs bash

# Mount current directory into container
docker run -d \
  --name nginx-web \
  -v /home/user/website:/usr/share/nginx/html:ro \
  -p 80:80 \
  nginx:latest

# Bind mount for development
docker run -it \
  --name node-dev \
  -v $(pwd):/app \
  -w /app \
  -p 3000:3000 \
  node:20 \
  npm run dev

# Mount config file
docker run -d \
  --name nginx-custom \
  -v /etc/nginx/nginx.conf:/etc/nginx/nginx.conf:ro \
  -p 80:80 \
  nginx:latest

Volumes with Docker Compose

hljs yaml

# docker-compose.yml
version: '3.8'

services:
  db:
    image: mysql:8.0
    environment:
      MYSQL_ROOT_PASSWORD: StrongPass123!
      MYSQL_DATABASE: myapp
    volumes:
      - mysql-data:/var/lib/mysql
      - ./init.sql:/docker-entrypoint-initdb.d/init.sql:ro
    ports:
      - "3306:3306"

  app:
    image: myapp:latest
    volumes:
      - app-uploads:/app/uploads
      - ./config:/app/config:ro
    depends_on:
      - db

volumes:
  mysql-data:
    driver: local
  app-uploads:
    driver: local

Volume Backup and Restore

hljs bash

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

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

# Copy volume to another host
docker run --rm \
  -v mysql-data:/data \
  alpine tar czf - -C /data . | ssh user@remote-host 'docker run --rm -i -v mysql-data:/data alpine tar xzf - -C /data'

Docker Network Modes

Bridge Network (Default)

hljs bash

# Default bridge network
docker run -d --name web nginx
# Container gets 172.17.0.x IP

# Create custom bridge network
docker network create myapp-network

# Connect container to custom network
docker run -d \
  --name web \
  --network myapp-network \
  nginx

docker run -d \
  --name db \
  --network myapp-network \
  -e MYSQL_ROOT_PASSWORD=StrongPass123! \
  mysql:8.0

# Containers on custom network can find each other by name
docker exec web ping db  # Access via 'db' hostname

Host Network

hljs bash

# Run in host network mode (Linux only)
docker run -d \
  --name nginx-host \
  --network host \
  nginx
# Container uses host's network interface directly
# No port mapping needed

None Network

hljs bash

# Container with no network access
docker run -d \
  --name isolated \
  --network none \
  myapp

Docker Network Management

hljs bash

# List networks
docker network ls

# Inspect network details
docker network inspect myapp-network

# Create network with custom subnet
docker network create \
  --driver bridge \
  --subnet 172.20.0.0/16 \
  --gateway 172.20.0.1 \
  myapp-network

# Connect container to network
docker network connect myapp-network existing-container

# Disconnect container from network
docker network disconnect myapp-network existing-container

# Remove network
docker network rm myapp-network

# Remove unused networks
docker network prune

Networks with Docker Compose

hljs yaml

# docker-compose.yml
version: '3.8'

services:
  frontend:
    image: nginx:latest
    networks:
      - frontend-net
    ports:
      - "80:80"

  backend:
    image: myapp:latest
    networks:
      - frontend-net
      - backend-net

  db:
    image: mysql:8.0
    networks:
      - backend-net
    environment:
      MYSQL_ROOT_PASSWORD: StrongPass123!

networks:
  frontend-net:
    driver: bridge
  backend-net:
    driver: bridge
    internal: true  # No external access

Overlay Network (Docker Swarm)

hljs bash

# Initialize Swarm
docker swarm init

# Create overlay network
docker network create \
  --driver overlay \
  --attachable \
  swarm-network

# Create service on overlay network
docker service create \
  --name web \
  --network swarm-network \
  --replicas 3 \
  nginx

Troubleshooting Container Communication

hljs bash

# Get container IP address
docker inspect CONTAINER_NAME | grep IPAddress

# Ping test from inside container
docker exec CONTAINER_NAME ping -c 3 OTHER_CONTAINER

# Curl test from inside container
docker exec CONTAINER_NAME curl http://other-service:8080/health

# View network connections
docker exec CONTAINER_NAME netstat -tulpn

# Test DNS resolution
docker exec CONTAINER_NAME nslookup db

# Network statistics
docker stats CONTAINER_NAME

Conclusion

Docker volume and network management are the cornerstones of production-grade container infrastructure. Store your data safely with named volumes, isolate your containers with custom bridge networks, and define your entire infrastructure as code with Docker Compose. With these configurations on REXE servers, you can build reliable and scalable container environments.

Docker Volume and Network Management: Persistent Storage and Network Configuration

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