Docker Networking Lecture Notes

Introduction

• Docker Containers: Lightweight, fast, and widely used.
• Networking Mystery: Understanding how Docker networking works is crucial.
• Different Network Types: There are seven different network types in Docker.
• Objective: Explore the different Docker network types and their functions.

Requirements

• Prerequisites: Basic knowledge of Docker containers.
• Host Setup: A Linux virtual machine (VM) with Docker installed. Example used is Ubuntu Desktop on VirtualBox.
• Network Configuration: Use bridge adapter in VM settings to connect directly to the home network.

Default Bridge Network

• Installation: Install Docker on the Ubuntu VM.
• Check Interfaces: Before Docker install, ip addr show shows loopback and main network interface. Post-install, Docker adds docker0 virtual bridge interface.
• Docker Commands: docker network ls lists networks, docker run launches containers, docker network inspect bridge inspects networks.
• Deploying Containers: Use docker run -dit --rm --name <name> <image> to deploy containers. Containers get virtual interfaces connected to docker0 bridge.
• Interaction: Containers can communicate through their bridged network interfaces.
• Port Exposure: Manually expose ports using -p option while deploying containers to access services from the host network.

User-Defined Bridge Network

• Creation: Create using docker network create <name>.
• Benefits: Better isolation and built-in DNS for container communication.
• Commands: Use docker run --network <network_name> to deploy containers to this network.
• Container Communication: Containers in user-defined networks can communicate by name due to DNS.

Host Network

• Function: Containers share the host’s network stack.
• Deployment: Use --network host without port exposure.
• Scenario: Good for deploying VPN services where container needs direct host network access.

MacVLAN Network

• Concept: Connects containers directly to the physical network.
• Setup: Use docker network create -d macvlan --subnet=<subnet> --gateway=<gateway> -o parent=<interface>.
• Advantages: Containers get unique MAC addresses and can directly access the home network.
• Challenges: Requires promiscuous mode enabled on the switch port; no DHCP, static IP assignment required.

IPvlan Network

• Modes: L2 (Layer 2) and L3 (Layer 3).
• L2 Mode: Similar to MacVLAN but shares the host’s MAC address instead of having unique ones.
• L3 Mode: Focuses on IP routing, making host a router for containers. Uses static routes to connect networks.
• Command: Use --ipvlan-l3 options for creating an L3 network.

Overlay Network

• Usage: For multi-host Docker Swarm setups, interconnects containers across different hosts.
• Scenario: Ideal for large-scale applications with multiple Docker hosts.

None Network

• Feature: Provides total network isolation.
• Deployment: Use --network none to create containers with no network access, only loopback interface.
• Usage: For maximum isolation and security.

Conclusion

• Networking Skills: Docker networking is a vital skill for modern container-based applications.
• Application: Experiment with different networks in a lab setup and include the experience on your resume.
• Favorite Networks: Highlight favorites like MacVLAN and IPvlan for their advanced networking capabilities.
• Engagement: Encouraged to explore further and interact with each network type.

Additional Sections

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