4.4 Lab - Advanced Docker Networking with Calico Plugin

Introduction

This lab is designed to provide an in-depth exploration into advanced Docker networking, highlighting the creation and management of overlay networks, and extending Docker's networking capabilities with the Calico network plugin. Calico provides additional networking features such as network policies for enhanced security and performance. Utilizing the Nano editor in a Linux environment, participants will gain hands-on experience in configuring sophisticated Docker networks.

Objectives

• Understand and implement Docker overlay networks.
• Install and configure the Calico network plugin for Docker.
• Create and apply Calico network policies to manage container communications effectively.

Lab Steps

Part 1: Setting Up Overlay Networks

Step 1: Preparing Your Environment

• Ensure Docker and Nano are installed on your Linux system. Install Nano if necessary with sudo apt-get install nano.

Step 2: Initializing Docker Swarm

• If not already configured, initialize Docker Swarm:

  docker swarm init
  

Step 3: Creating an Overlay Network

• Create an overlay network named overlay-net:

  docker network create --driver overlay overlay-net
  

Step 4: Deploying a Service

• Deploy a service to your overlay network:

  docker service create --name web-service --network overlay-net nginx
  

Part 2: Implementing Calico for Advanced Networking

Step 5: Installing Calico

• Follow the official Calico installation instructions for Docker environments. Installation usually involves downloading Calico components and running the Calico node. For the latest commands, refer to the Calico documentation.

Step 6: Creating a Calico Network

• Create a Docker network utilizing the Calico driver:

  docker network create --driver calico --ipam-driver calico-ipam calico-net
  

Step 7: Running Containers on the Calico Network

• Run two containers attached to calico-net:

  docker run --net calico-net --name container1 -dit alpine sh
  docker run --net calico-net --name container2 -dit alpine sh
  

Step 8: Creating and Applying a Calico Network Policy

• Use Nano to create a network policy file named policy.yaml. This policy will allow ICMP (ping) traffic between containers in calico-net.

  • Open Nano to edit policy.yaml:

    nano policy.yaml
    

  • Insert the following policy details, which define a policy to allow ping requests:

    apiVersion: projectcalico.org/v3
    kind: GlobalNetworkPolicy
    metadata:
      name: allow-ping
    spec:
      selector: all()
      types:
      - Ingress
      - Egress
      ingress:
      - action: Allow
        protocol: ICMP
      egress:
      - action: Allow
    

  • Save and exit Nano (CTRL+O, Enter, CTRL+X).

• Apply the policy using Calico's command-line tool (ensure calicoctl is installed and configured):

  calicoctl apply -f policy.yaml
  

Summary

Throughout this lab, you've successfully navigated the complexities of Docker's advanced networking features, from setting up overlay networks to integrating and configuring the Calico network plugin. The hands-on experience with creating and deploying services across overlay networks, coupled with the enhanced security and performance capabilities provided by Calico's network policies, equips you with the knowledge to manage intricate Docker networking scenarios. This lab underscores the importance of robust network configurations and policies in maintaining secure, efficient communication across containerized applications.