Difference between revisions of "Docker/C3/Docker-Networking/English"

Title Slide

Learning Objectives

• Fundamentals of Docker networking.
• Connecting containers and establishing communication links.
• Configuring port exposure and service exposure.
• Deleting docker network

System Requirements

• Ubuntu Linux OS version 22.04
• Docker version 27.0.2

Prerequisite

• You must have basic knowledge of using Linux terminal
• For pre-requisite Linux tutorials, please visit this website

Fundamentals of Docker networking

• Docker networking involves various components and configurations
• Docker uses network namespaces to isolate network resources.
• Docker facilitates this through network links and service discovery mechanisms

Types of Docker networks

• Bridge Network:It is the default network type
• Host Network: The Containers share the host’s network stack
• Overlay Network: It enables communication between containers
• Macvlan Network: It assigns a MAC address to each container, making it appear as a physical device
• None Network: It disables networking for the container

Create a Docker network Type command docker network create newnetwork in terminal

Highlight network id

Let us first create a docker network.

To create a docker network

Type docker space network space create space newnetwork and press Enter

Here, newnetwork is the name of the network.

We can see a network id as output related to the created network.

docker network ls

docker network ls

Here you can see all the docker networks

with newnetwork

Highlight container id

We will be using a nginx docker image.

We'll start a container and connect it to the network using the command as shown.

This command runs a container named container1 and connects it to newnetwork.

Highlight container id

Type the command as shown.

Here the nginx container is serving as the server

And we will use the curl container to act as the client

Now, both containers are connected to the same network.

They can communicate with each other.

Highlight response

The containers will return a webpage response.

The response will contain nginx welcome page in html format

Ports expose Docker container services to the host or other networks

docker run -d -p 8080:80 nginx

docker space run space hyphen d space hyphen p space 8080:80 space nginx and press Enter

This command exposes port 80 of the container nginx to port 8080 on the host.

Now, service is running on port 80 within the container.

We can access this via port 8080 on the host machine

Type the URL http://localhost:8080

Open the web browser and type the url

http://localhost:8080

docker network ls

All the docker network with network id will appear

Let us see how to delete a created network.

Type

docker space network space ls

Here we can see all the docker networks

Let us remove the third network from the list.

copy the network_id

Type docker space network space rm and paste the id.

To fix this error we have to first stop all the containers using the network newnetwork

Type the command as shown.

It displays the container id that are stopped which used newnetwork as network

Type docker network ls

To remove the network we will use the remove command with network id.

Let us remove the third network from the list.

copy the network id

Type docker space network space rm and paste the id.

The network newnetwork is successfully removed with network id as shown.

A warning will appear

WARNING! This will remove all custom networks not used by at least one container.

Are you sure you want to continue? [y/N]

For that type

docker space network space prune

A warning will appear.

Type y and press Enter to continue removing the docker networks

Summary

In this tutorial, we learnt about

• Fundamentals of Docker networking
• Connecting containers and establishing communication links
• Configuring port exposure and service exposure
• Deleting docker network

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