Network simulation with Containerlab

Containerlab is a tool for provisioning networking labs built with containers. It is free.

Before we begin, The following requirements must be satisfied to let containerlab tool run successfully:

• A user should have sudo privileges to run containerlab.
• A Linux server/VM and Docker installed.
• Load container images (e.g. Nokia SR Linux, Arista cEOS) that are not downloadable from a container registry. Containerlab will try to pull images at runtime if they do not exist locally.

first we need install docker, in this case we use ubuntu 24.04

Remove all old version of docker

for pkg in docker.io docker-doc docker-compose docker-compose-v2 podman-docker containerd runc; do sudo apt-get remove $pkg; done

Set up Docker’s apt Repository

# Add Docker's official GPG key:
sudo apt-get update
sudo apt-get install ca-certificates curl
sudo install -m 0755 -d /etc/apt/keyrings
sudo curl -fsSL <https://download.docker.com/linux/ubuntu/gpg> -o /etc/apt/keyrings/docker.asc
sudo chmod a+r /etc/apt/keyrings/docker.asc

# Add the repository to Apt sources:
echo \\\\
  "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] <https://download.docker.com/linux/ubuntu> \\\\
  $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | \\\\
  sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
sudo apt-get update

Install docker

sudo apt-get install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

Verify the docker successfully installed

docker version

Begin install the containerlab

To install all components at once, run the following command on any of the supported OSes:

curl -sL <https://containerlab.dev/setup> | sudo -E bash -s "all"

Once installed, containerlab manages the labs defined in the so-called topology definition, clab files.

Deploying a lab

example topology:

user can write a topology definition file from scratch example:

mkdir ~/demolab
cd ~/demolab
nano demolab.clab.yaml

name: demolab

topology:
  nodes:
    srl_sw1:
      kind: nokia_srlinux
      image: ghcr.io/nokia/srlinux
    srl_sw2:
      kind: nokia_srlinux
      image: ghcr.io/nokia/srlinux

  links:
    - endpoints: ["srl_sw1:e1-1", "srl_sw2:e1-1"]

on that topology we use nokia srlinux image, before we deploy the lab we can pull that images with

docker pull ghcr.io/nokia/srlinux

Deploy lab

containerlab deploy

deploy command will automatically lookup a file matching the *.clab.y*ml patter to select it.

Accessing the node:

now we can see two container is running indicated two nokia srl switch is running.
to access the node we can use ssh

ssh admin@clab-demolab-srl-sw1

Removing Lab

To remove the lab, use the destroy command that takes a topology file as an argument:

containerlab destroy