Estimated reading time: 6 minutes
Last updated on November 8th, 2024 at 04:58 pm
Table of Contents
Understanding Docker Networking Basics
Docker containers are lightweight units to run your application but effective communication is key to running it smoothly. Docker networks are the foundation for containerizing the application, providing a way to communicate with each other and outside the world.
Docker uses the namespaces concept to isolate containers including a network namespace by creating the virtual network environment. Containers within the same virtual network can communicate with each other out-of-the-box.
Type of Docker Networks
Docker provides the various networking drivers:
Bridge:
This is the default network driver and the most commonly used one allows to communicate containers with each other using an IP address.

Host:
Rather than creating a different virtual network, it connects the container directly to the Host network. No need to port forwarding instead explore directly on Host IP.

Overlay:
Allow to connect multiple Docker daemon as a single overlay network used in Docker Swarm mode.

Macvlan:
Assign the container a physical MAC address and provide a way to communicate directly on the host network.
IPvlan:
Unlike Macvlan, all IPvlan share the same MAC address as the physical host. Enable communication even on the external network.
Additional Reading:
Docker Network Overlay vs Bridge – Ultimate Difference
Docker Network External vs Internal: Simplified 3-Minute!
Implementing Docker Network Best Practices
1. Choose the Right Network Driver
Use the right tool for the job: Don’t just use the default bridge Docker network, select the right driver based on your needs.
The bridge network works for simple deployment without extra configuration while the overlay network is best suited for the Docker swarm
2. User-Defined Networks for Improved Isolation
As mentioned don’t rely on the default bridge network, create your custom networks for your application. Custom networks provide isolation and control over communication between them.
You can create a custom network with the below command:
# Define network
docker network create frontend_network
# Run container attach to network
docker run --network=frontend_network nginx:latest
3. Clear & Maintainable Naming Conventions
Giving a meaningful name to the Docker network makes it easy to remember and manage, especially when you run multiple large-scale deployments.
Docker Network Best Practices – Use descriptive names such as “backend_network” or “frontend_network” to define the clear purpose and avoid using generic names.
10 Docker Container Naming Convention Best Practices
Ensuring Security and Efficiency in Docker Networks
4. Network Segmentation for Security & Performance
Keeping your container in the same network might sound easy but it’s not secure.
Imagine your Database and Webserver in the same network, your Webserver doesn’t need access to the Database, and if the Webserver is compromised attacker can have access to the Database container.
Docker Network best practices to divide your networks based on application and security requirements that prevent unauthorized access and improve performance.
# Custom network for WebServer
docker network create frontend_network
# Custom network for Database or Backend
docker network create backend_network
Docker Container Security Cheatsheet: Don’t Get Hacked🔐
5. Avoid Subnet Overlaps
Subet is a set of IPs you can use from the bigger chuck of IPs, having the same IPs in the network can create a conflict.
Docker Network Best Practices – Avoid subnet overlapping in the Docker network to prevent connectivity issues. You can use the Subnet Calculator for planning your network range.
You can check your current Docker network configuration with docker network inspect
:
docker network inspect
6. Only Expose Required Ports
Exposing the unnecessary port to the host or external network can open up the attack surface. You don’t want to expose your Database container port to the host or external access from the internet.
Docker Network best practices – Only expose necessary container ports to enhance security and reduce the attack surface.
docker run -d -p 80:80 nginx_web_server
Carefully use the -p
flag when running the Docker container.
7. Leverage Docker Compose for Network Management
It’s challenging to manage multiple Docker container applications fortunately Docker Compose provides a simplified way to manage multi-container applications and the network.
Rather than relying on the network when running the individual container, Docker Network best practices use Docker Compose to write the whole service and network stack in the configuration file.
version: '3.8'
services:
# Frontend service
frontend:
image: nginx:latest
networks:
- frontend # Connect to the frontend network
ports:
- "80:80"
# Backend service (Python app)
backend:
image: python:latest
networks:
- backend # Connect to the backend network
networks:
# Define separate networks for frontend and backend
frontend:
backend:
Optimizing Communication and Troubleshooting in Docker Networks
8. Use DNS Resolution for Service Discovery
If you use the default Docker bridge network, you can’t communicate with the container using the name. Use the custom Docker network to leverage the built-in DNS resolution for service discovery using container names only.
You can use the service name to communicate between the containers:
DATABASE_URL=mysql://db_user:db_password@database:3306/db_name
9. Write Documentation for Effective Network Management
Maintain the comprehensive documentation for network-related configuration, diagrams, and important links. Good documentation helps in the long run for troubleshooting and effective network management.
Docker Network best practices, keep track of your changes, and update consistently using the source code management tools such as GIT.
Documentation is a love letter that you write to yourself six months from now.
Kathy Sierra
10. Monitoring & Logging: Increase Performance & Reliability
The things you can measure you can control. Keep an eye on your Docker container metrics for optimal performance and fine-tuning. Monitor network performance and bandwidth for your container containers.
Docker Network Best Practices – You can use tools like Prometheus and Grafana for monitoring and ELK stack, Elastic Search, Loagstash, and Kibana. for logging.
Conclusion: Best Practices for Docker Networking Success
Recap what we have learned from the 10 Docker Network Best Practices and implement it.
Key takeaways:
- Choose the Right Network Driver
- User-Defined Networks for Improved Isolation
- Clear & Maintainable Naming Conventions
- Network Segmentation for Security & Performance
- Avoid Subnet Overlaps
- Only Expose Required Ports
- Leverage Docker Compose for Network Management
- Use DNS Resolution for Service Discovery
- Write Documentation for Effective Network Management
- Monitoring & Logging: Increase Performance & Reliability
Stay updated with the latest trends and best practices for the Docker network. Continuously monitor and optimize your network configuration