Exploring Docker Networking and Understanding Cloud Networking

Introduction

Containers are heavily used in modern cloud environments. Cloud services such as Kubernetes, Amazon ECS, Azure Kubernetes Service (AKS), and Google Kubernetes Engine (GKE) rely on container networking.

In this tutorial, you will create multiple Docker containers and explore how they communicate using Docker networks.

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Lab Environment

Host:

• Windows 11

• Docker Desktop

Containers:

• PHP Container

• MySQL Container

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Part 1: Default Bridge Network

Run:

docker run -d --name web nginx

Check:

docker network ls

Expected:

bridge
host
none

Inspect:

docker network inspect bridge

Observation

Container automatically joins bridge network.

Cloud Networking Analogy

Equivalent to:

Virtual Network
   |
 Multiple VMs

or

AWS VPC

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Part 2: Create Custom Network

Create:

docker network create appnet

Verify:

docker network ls

Cloud Networking Analogy

Equivalent to:

AWS VPC
Azure VNet
Google VPC

A custom Docker network acts like a cloud virtual network.

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Part 3: Connect Containers

Run MySQL:

docker run -d ^
--name db ^
--network appnet ^
mysql:8

Run PHP:

docker run -d ^
--name web ^
--network appnet ^
php:8.3-apache

Inspect:

docker network inspect appnet

Observation

Containers discover each other automatically.

PHP can reach:

db

without knowing the IP address.

Cloud Networking Analogy

Equivalent to:

Private DNS
Service Discovery
Internal Load Balancer

used in Kubernetes and cloud platforms.

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Part 4: Port Mapping

Run:

docker run -d ^
-p 8080:80 ^
nginx

Access:

http://localhost:8080

Observation

External users access container through mapped port.

Cloud Networking Analogy

Equivalent to:

Public IP
Load Balancer
NAT Rule

Concept:

Internet
     |
 Port Mapping
     |
 Container

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Part 5: Container Isolation

Create:

docker network create backend

Run database:

docker run -d ^
--name db ^
--network backend ^
mysql:8

Do not publish ports.

Observation

Database is hidden.

Only backend applications can access it.

Cloud Networking Analogy

Equivalent to:

Private Database Subnet

used for:

• Amazon RDS

• Azure SQL

• Cloud SQL

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Part 6: Docker Compose Architecture

Example:

services:

  web:
    image: php:8.3-apache

  db:
    image: mysql:8

Docker Compose automatically creates:

Application Network

Cloud Networking Analogy

Equivalent to:

Infrastructure as Code

such as:

• AWS CloudFormation

• Azure ARM Templates

• Terraform

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Part 7: Mapping Docker Networking to Cloud Networking

Docker	Cloud Equivalent
Bridge Network	VPC / VNet
Container	VM / Pod
Custom Network	Private Network
Port Mapping	Public IP / NAT
Container DNS	Service Discovery
Docker Compose	Infrastructure as Code
Overlay Network	SDN Overlay
Container Cluster	Kubernetes Cluster

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What Students Learned

After completing this tutorial students understand:

• Container networking

• Service discovery

• Port publishing

• Network isolation

• Private and public services

• Cloud-native networking concepts

These concepts directly prepare students for Kubernetes, ECS, AKS, GKE, VPCs, VNets, and cloud load balancing.