Getting started with Network Automation using Vagrant + Libvirt

2022-07-20 4013 words 19 minutes

Contents

In this post, I’m going to walk you through how to set up an environment that can be used for testing what’s been called these days “Cloud Native Data Centers”, including underlay/overlay protocols, network automation scripts, zero-touch provisioning, monitoring, observability amongst many other things.

In order to build this, we’re going to use Vagrant combined with Libvirt, which uses KVM as the hypervisor. I’ve chosen Libvirt over Virtualbox due to its better scalability and portability beyond running some small tests in your home PC¹. You don’t normally see Virtualbox in Linux servers, but you do see KVM.

The great think about Vagrant is that it uses text files to describe the entire network topology, this allows us to use git for version control and to automate the creation of the test environment - no need to waste time pointing and clicking in a GUI.

There’s a bit of a learning curve understanding the text file that Vagrant uses to describe the topology (called Vagrantfile). Hopefully, after you read this blog post, you will be able to create you own topologies without any issues.

Network Topology

We’re going to build the following 3-stage Clos topology made up of two spines, four leaves, and two servers. Additionally, we have an out-of-band management network (purple) where all devices are connected to via their management interfaces through a Libvirt virtual bridge. Lastly, we have a mgmt-server connected to the virtual bridge only.

/posts/getting-started-with-vagrant-libvirt/images/base_topology.png — 3-stage Clos Network

OS versions

Switches: Cumulus VX 3.7.15
Servers: Ubuntu 20.04

Management IP Addressing

Assigned all via DHCP. The MGMT network has been configured explicitly in the Vagranfile to be 172.16.100.0/24.

The assigned DHCP allocations can bee seen running the following command:

virsh net-dhcp-leases vagrant-libvirt

If you’re not using the default vagrant-libvirt network, then you need to change the name there.

Installing Vagrant and Libvirt plugging²

After spending a lot of time trying to figure out how to make the libvirt plugin work with Vagrant (there seems to be tons of problems due to different versions being used) I’ve figured out that if you just run this script, it all works immediately:

https://github.com/vagrant-libvirt/vagrant-libvirt-qa/blob/main/scripts/install.bash

Click to see the above script - to run it: 'bash install.bash'

        
        
        
    
#!/bin/bash

set -o errexit -o pipefail -o noclobber -o nounset

DPKG_OPTS=(
    -o Dpkg::Options::="--force-confold"
)
VAGRANT_LIBVIRT_VERSION=${VAGRANT_LIBVIRT_VERSION:-"latest"}

function restart_libvirt() {
    service_name=${1:-libvirtd}
    # it appears there can be issues with libvirt being started before certain
    # packages that are required for create behaviour on first run. Restart to
    # ensure the daemon picks up the latest environment and can create a VM
    # on the first attempt. Otherwise will need to reboot
    sudo systemctl restart ${service_name}
}

function setup_apt() {
    export DEBIAN_FRONTEND=noninteractive
    export DEBCONF_NONINTERACTIVE_SEEN=true

    sudo sed -i "s/# deb-src/deb-src/" /etc/apt/sources.list
    sudo -E apt-get update
    sudo -E apt-get -y "${DPKG_OPTS[@]}" upgrade
    sudo -E apt-get -y build-dep vagrant ruby-libvirt
}

function setup_arch() {
    sudo pacman -Suyu --noconfirm --noprogressbar
    sudo pacman -Qs 'iptables' | grep "local" | grep "iptables " && sudo pacman -Rd --nodeps --noconfirm iptables
    # need to remove iptables to allow ebtables to be installed
    sudo pacman -S --needed --noprogressbar --noconfirm  \
        autoconf \
        automake \
        binutils \
        bridge-utils \
        dnsmasq \
        git \
        gcc \
        iptables-nft \
        libvirt \
        libxml2 \
        libxslt \
        make \
        openbsd-netcat \
        pkg-config \
        qemu \
        ruby \
        wget \
        ;
    sudo systemctl enable --now libvirtd
}

function setup_centos_7() {
    sudo yum -y update
    sudo yum -y install centos-release-qemu-ev
    sudo yum -y update
    sudo yum -y install \
        autoconf \
        automake \
        binutils \
        cmake \
        gcc \
        git \
        libguestfs-tools \
        libvirt \
        libvirt-devel \
        make \
        qemu \
        qemu-kvm-ev \
        ruby-devel \
        wget \
        ;
    restart_libvirt
}

function setup_centos() {
    sudo dnf -y update
    sudo dnf -y install \
        @virt \
        autoconf \
        automake \
        binutils \
        byacc \
        cmake \
        gcc \
        gcc-c++ \
        git \
        libguestfs-tools \
        libvirt \
        libvirt-devel \
        make \
        qemu-kvm \
        rpm-build \
        ruby-devel \
        wget \
        zlib-devel \
        ;
    restart_libvirt
}

function setup_debian() {
    setup_apt
    sudo -E apt-get -y "${DPKG_OPTS[@]}" install \
        dnsmasq \
        ebtables \
        git \
        libvirt-clients \
        libvirt-daemon \
        libvirt-daemon-system \
        qemu \
        qemu-system-x86 \
        qemu-utils \
        wget \
        ;
    restart_libvirt
}

function setup_fedora() {
    sudo dnf -y update
    sudo dnf -y install \
        @virtualization \
        autoconf \
        automake \
        binutils \
        byacc \
        cmake \
        gcc \
        gcc-c++ \
        git \
        libguestfs-tools \
        libvirt-devel \
        make \
        wget \
        zlib-devel \
        ;
    restart_libvirt
}

function setup_ubuntu_1804() {
    setup_apt
    sudo -E apt-get -y "${DPKG_OPTS[@]}" install \
        git \
        libvirt-bin \
        qemu \
        wget \
        ;
    restart_libvirt
}

function setup_ubuntu() {
    setup_apt
    sudo -E apt-get -y "${DPKG_OPTS[@]}" install \
        git \
        libvirt-clients \
        libvirt-daemon \
        libvirt-daemon-system \
        qemu \
        qemu-system-x86 \
        qemu-utils \
        wget \
        ;
    restart_libvirt
}

function setup_distro() {
    local distro=${1}
    local version=${2:-}

    if [[ -n "${version}" ]] && [[ $(type -t setup_${distro}_${version} 2>/dev/null) == 'function' ]]
    then
        eval setup_${distro}_${version}
    else
        eval setup_${distro}
    fi
}


function download_vagrant() {
    local version=${1}
    local pkgext=${2}
    local pkg="vagrant_${1}_x86_64.${pkgext}"

    wget --no-verbose https://releases.hashicorp.com/vagrant/${version}/${pkg} -O /tmp/${pkg}.tmp
    mv /tmp/${pkg}.tmp /tmp/${pkg}
}

function install_rake_arch() {
    sudo pacman -S --needed --noprogressbar --noconfirm  \
        ruby-bundler \
        rake
}

function install_rake_centos() {
    sudo yum -y install \
        rubygem-bundler \
        rubygem-rake
}

function install_rake_debian() {
    sudo apt install -y \
        bundler \
        rake
}

function install_rake_fedora() {
    sudo dnf -y install \
        rubygem-rake
}

function install_rake_ubuntu() {
    install_rake_debian $@
}

function install_vagrant_arch() {
    sudo pacman -S --needed --noprogressbar --noconfirm  \
        vagrant
}

function install_vagrant_centos() {
    local version=$1

    download_vagrant ${version} rpm
    sudo -E rpm -Uh --force /tmp/vagrant_${version}_x86_64.rpm
}

function install_vagrant_debian() {
    local version=$1

    download_vagrant ${version} deb
    sudo -E dpkg -i /tmp/vagrant_${version}_x86_64.deb
}

function install_vagrant_fedora() {
    install_vagrant_centos $@
}

function install_vagrant_ubuntu() {
    install_vagrant_debian $@
}

function build_libssh() {
    local dir=${1}

    mkdir -p ${dir}-build
    pushd ${dir}-build
    cmake ${dir} -DOPENSSL_ROOT_DIR=/opt/vagrant/embedded/
    make
    sudo cp lib/libssh* /opt/vagrant/embedded/lib64
    popd
}

function build_krb5() {
    local dir=${1}

    pushd ${dir}/src
    ./configure
    make
    sudo cp -P lib/crypto/libk5crypto.* /opt/vagrant/embedded/lib64/
    popd
}

function setup_rpm_sources_centos() {
    typeset -n basedir=$1
    pkg="$2"
    rpmname="${3:-${pkg}}"

    [[ ! -d ${pkg} ]] && git clone https://git.centos.org/rpms/${pkg}
    pushd ${pkg}
    nvr=$(rpm -q --queryformat "${pkg}-%{version}-%{release}" ${rpmname})
    nv=$(rpm -q --queryformat "${pkg}-%{version}" ${rpmname})
    git checkout $(git tag -l | grep "${nvr}\$" | tail -n1)
    into_srpm.sh -d c8s
    pushd BUILD
    tar xf ../SOURCES/${nv}.tar.*z

    basedir=$(realpath ${nv})
    popd
    popd
}

function patch_vagrant_centos_8() {
    mkdir -p patches
    pushd patches
    [[ ! -d centos-git-common ]] && git clone https://git.centos.org/centos-git-common
    export PATH=$(readlink -f ./centos-git-common):$PATH
    chmod a+x ./centos-git-common/*.sh

    setup_rpm_sources_centos LIBSSH_DIR libssh
    build_libssh ${LIBSSH_DIR}

    setup_rpm_sources_centos KRB5_DIR krb5 krb5-libs
    build_krb5 ${KRB5_DIR}

    popd
}

function setup_rpm_sources_fedora() {
    typeset -n basedir=$1
    pkg="$2"
    rpmname="${3:-${pkg}}"

    nvr=$(rpm -q --queryformat "${pkg}-%{version}-%{release}" ${rpmname})
    nv=$(rpm -q --queryformat "${pkg}-%{version}" ${rpmname})
    mkdir -p ${pkg}
    pushd ${pkg}

    [[ ! -e ${nvr}.src.rpm ]] && dnf download --source ${rpmname}
    rpm2cpio ${nvr}.src.rpm | cpio -imdV
    rm -rf ${nv}
    tar xf ${nv}.tar.*z

    basedir=$(realpath ${nv})
    popd
}

function patch_vagrant_fedora() {
    mkdir -p patches
    pushd patches

    setup_rpm_sources_fedora LIBSSH_DIR libssh
    build_libssh ${LIBSSH_DIR}

    setup_rpm_sources_fedora KRB5_DIR krb5 krb5-libs
    build_krb5 ${KRB5_DIR}

    popd
}

function install_vagrant() {
    local version=${1}
    local distro=${2}
    local distro_version=${3:-}

    echo "Installing vagrant version '${version}'"

    eval install_vagrant_${distro} ${version}

    if [[ -n "${distro_version}" ]] && [[ $(type -t patch_vagrant_${distro}_${distro_version} 2>/dev/null) == 'function' ]]
    then
        echo "running patch_vagrant_${distro}_${distro_version}"
        eval patch_vagrant_${distro}_${distro_version}
    elif [[ $(type -t patch_vagrant_${distro} 2>/dev/null) == 'function' ]]
    then
        echo "running patch_vagrant_${distro}"
        eval patch_vagrant_${distro}
    else
        echo "no patch functions configured for ${distro} ${distro_version}"
    fi
}

function install_vagrant_libvirt() {
    local distro=${1}

    echo "Testing vagrant-libvirt version: '${VAGRANT_LIBVIRT_VERSION}'"
    if [[ "${VAGRANT_LIBVIRT_VERSION:0:4}" == "git-" ]]
    then
        eval install_rake_${distro}
        if [[ ! -d "./vagrant-libvirt" ]]
        then
            git clone https://github.com/vagrant-libvirt/vagrant-libvirt.git
        fi
        pushd vagrant-libvirt
        git checkout ${VAGRANT_LIBVIRT_VERSION#git-}
        rm -rf ./pkg
        rake build
        vagrant plugin install ./pkg/vagrant-libvirt-*.gem
        popd
    elif [[ "${VAGRANT_LIBVIRT_VERSION}" == "latest" ]]
    then
        vagrant plugin install vagrant-libvirt
    else
        vagrant plugin install vagrant-libvirt --plugin-version ${VAGRANT_LIBVIRT_VERSION}
    fi
}


OPTIONS=o
LONGOPTS=vagrant-only,vagrant-version:

# -pass arguments only via   -- "$@"   to separate them correctly
! PARSED=$(getopt --options=$OPTIONS --longoptions=$LONGOPTS --name "$0" -- "$@")
if [[ ${PIPESTATUS[0]} -ne 0 ]]
then
    echo "Invalid options provided"
    exit 2
fi

eval set -- "$PARSED"

VAGRANT_ONLY=0

while true; do
    case "$1" in
        -o|--vagrant-only)
            VAGRANT_ONLY=1
            shift
            ;;
        --vagrant-version)
            VAGRANT_VERSION=$2
            shift 2
            ;;
        --)
            shift
            break
            ;;
        *)
            echo "Programming error"
            exit 3
            ;;
    esac
done

echo "Starting vagrant-libvirt installation script"

DISTRO=${DISTRO:-$(awk -F= '/^ID=/{print $2}' /etc/os-release | tr -d '"' | tr '[A-Z]' '[a-z]')}
DISTRO_VERSION=${DISTRO_VERSION:-$(awk -F= '/^VERSION_ID/{print $2}' /etc/os-release | tr -d '"' | tr '[A-Z]' '[a-z]' | tr -d '.')}

[[ ${VAGRANT_ONLY} -eq 0 ]] && setup_distro ${DISTRO} ${DISTRO_VERSION}

if [[ -z ${VAGRANT_VERSION+x} ]]
then
    VAGRANT_VERSION="$(
        wget -qO - https://checkpoint-api.hashicorp.com/v1/check/vagrant 2>/dev/null | \
            tr ',' '\n' | grep current_version | cut -d: -f2 | tr -d '"'
        )"
fi

install_vagrant ${VAGRANT_VERSION} ${DISTRO} ${DISTRO_VERSION}

[[ ${VAGRANT_ONLY} -eq 0 ]] && install_vagrant_libvirt ${DISTRO}

echo "Finished vagrant-libvirt installation script"

Once the installation is finished, let’s confirm everything works by trying to build an Ubuntu 20.04 VM.

You can find all the pre-built Vagrant boxes here just make sure you select libvirt as your provider - if you want to use an image not listed there, you’ll need to build it yourself.³

Let’s build our first Vagrant box. Below we have the equivalent to “hello world” for Vagrant:

        
        
        
    
lab@lab-HP-Z620-Workstation:~/NetworkAuto/clos$ vagrant init generic/ubuntu2004
A `Vagrantfile` has been placed in this directory. You are now
ready to `vagrant up` your first virtual environment! Please read
the comments in the Vagrantfile as well as documentation on
`vagrantup.com` for more information on using Vagrant.
lab@lab-HP-Z620-Workstation:~/NetworkAuto/clos$ vagrant up
Bringing machine 'default' up with 'libvirt' provider...
...output trimmed...
    default: Key inserted! Disconnecting and reconnecting using new SSH key...
==> default: Machine booted and ready!

As you can see, it created the Vagrantfile for us. Later, we’ll cover how to create this file from scratch.

And here, we have our Ubuntu VM up and running:

        
        
        
    
lab@lab-HP-Z620-Workstation:~/NetworkAuto/clos$ vagrant ssh
vagrant@ubuntu2004:~$ cat /etc/*release*  | grep VERSION
VERSION="20.04.4 LTS (Focal Fossa)"
VERSION_ID="20.04"
VERSION_CODENAME=focal
vagrant@ubuntu2004:~$

At this point, we’ve confirmed that Vagrant is working fine with the Libvirt plugging, so let’s delete the VM:

        
lab@lab-HP-Z620-Workstation:~/NetworkAuto/clos$ vagrant destroy -f
==> default: Removing domain...
==> default: Deleting the machine folder

Building ‘Vagrantfile’

As mentioned, Vagrant models everything using a file called “Vagrantfile” written in Ruby. In this section, we’re going to explore the following three individual components:

How Vagrant models devices
How Vagrant models P2P network links
How to run scripts at build time

I’m going to use the link between leaf01 and server01 to describe the above components of a Vagrantfile.

How to model a device

First, we set the following variables:

        
# Global Variables
SWITCH_OS = "CumulusCommunity/cumulus-vx"
SWITCH_VERSION = "3.7.15"
SERVER_OS= "generic/ubuntu2004"

Then, we define the device’s name, software and VM settings (we’re skipping the interfaces for now):

        
        
        
    
####################################
########## leaf01 config ###########
####################################

config.vm.define "leaf01" do |device|
    device.vm.hostname = "leaf01"
    device.vm.box = SWITCH_OS
    device.vm.box_version = SWITCH_VERSION
    device.vm.synced_folder ".", "/vagrant", disabled: true

    # VM settings
    device.vm.provider :libvirt do |domain|
        domain.memory = 768
        domain.cpus = 1
    end

#####################################
########## server01 config ##########
#####################################

config.vm.define "server01" do |device|
    device.vm.hostname = "server01"
    device.vm.box = SERVER_OS
    device.vm.synced_folder ".", "/vagrant", disabled: true

    # VM settings
    device.vm.provider :libvirt do |domain|
        domain.memory = 768
        domain.cpus = 1
    end

The vm.synced_folder set to disable is to stop default Vagrant behaviour of sharing the project folder with the VM. You can find more details here https://www.vagrantup.com/docs/synced-folders.

How to model a P2P link

Libvirt uses tunnels to represent P2P links based on:

Protocol: TCP or UDP
Source IP
Destination IP
Source Port
Destination Port

Each link needs to be uniquely identified, therefore using different IPs with the same port numbers or vice-versa is sufficient.
For the sake of simplicity, I’m keeping port 9999 unchanged and using different IPs to uniquely identify the link.

        
        
        
    
####################################
########## leaf01 config ##########
####################################

    # Link leaf01 swp3  ----> server01 eth1
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.18",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.17",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "swp3",
      auto_config: false


####################################
########## server01 config ##########
####################################

    # Link server01 eth1  ----> leaf01 swp3
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.17",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.18",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "eth1",
      auto_config: false

How to preconfigure devices

Another very useful feature of Vagrant is the option of running scripts at provisioning time. Once Vagrant builds the VM and can access it, it’ll run the scripts described in the Vagrantfile.

        
####################################
########## leaf01 config ##########
####################################

device.vm.provision "shell", inline: $switches_script, :args => ["leaf01", "3"]

####################################
########## server01 config ##########
####################################

device.vm.provision "shell", inline: $switches_script, :args => ["leaf01", "3"]

If your script doesn’t need arguments, you can delete the :args section.

Final Vagrantfile modelling our full network topology

Now, it’s time to see everything put together in the final Vagranfile, but before that, let’s discuss a few things.

First, how to set an env variable so that Vagrant’s default provider is change from Virtualbox to Libvirt:

        
# Set libvirt as the default provider
ENV['VAGRANT_DEFAULT_PROVIDER'] = 'libvirt'

Second, in the following table I’ve put together the tunnel IP mappings we’re going to use to build the P2P links in the Vagrantfile.

For the UDP ports I’m going to use the same across all links to make things easier (port 9999), only the IPs will change.

Device A	Intf A	IP A	UDP Port A	Device B	Intf B	IP B	UDP Port B
spine01	swp1	127.0.100.1	9999	leaf01	swp1	127.0.100.2	9999
spine01	swp2	127.0.100.3	9999	leaf02	swp1	127.0.100.4	9999
spine01	swp3	127.0.100.5	9999	leaf03	swp1	127.0.100.6	9999
spine01	swp4	127.0.100.7	9999	leaf04	swp1	127.0.100.8	9999
spine02	swp1	127.0.100.9	9999	leaf01	swp2	127.0.100.10	9999
spine02	swp2	127.0.100.11	9999	leaf02	swp2	127.0.100.12	9999
spine02	swp3	127.0.100.13	9999	leaf03	swp2	127.0.100.14	9999
spine02	swp4	127.0.100.15	9999	leaf04	swp2	127.0.100.16	9999
server01	eth1	127.0.100.17	9999	leaf01	swp3	127.0.100.18	9999
server04	eth1	127.0.100.19	9999	leaf04	swp3	127.0.100.20	9999

Third, the below changes:

        
        
        
    
    config.vm.provider :libvirt do |domain|
        # Change the default allowed number of interfaces from 8 to 52
        domain.nic_adapter_count = 52
        # Change the MGMT network subnet and its default name
        domain.management_network_name = "clos_fabric_mgmt_network"
        domain.management_network_address = "172.16.100.0/24"

Finally, here’s the final Vagranfile:

Click to see the full output

        
        
        
    
# -*- mode: ruby -*-
# vi: set ft=ruby :

# Set ENV variables
ENV['VAGRANT_DEFAULT_PROVIDER'] = 'libvirt'

# Global Variables
SWITCH_OS = "CumulusCommunity/cumulus-vx"
SWITCH_VERSION = "3.7.15"
SERVER_OS= "generic/ubuntu2004"


# Build scripts
$switches_script = <<EOF
sudo net add hostname $1
sudo net add vrf mgmt
sudo net add int swp1-$2
sudo net commit
EOF

$servers_script = <<EOF
sudo ip link set eth1 up
sudo apt-get install net-tools -y
sudo apt-get install inetutils-traceroute -y
sudo apt-get install lldpd -y
EOF

$mgmt_server_script = <<EOF
sudo apt-get install net-tools -y
sudo apt-get install inetutils-traceroute -y
sudo apt-get install lldpd -y
EOF

# Spine and Leaf Fabric - including servers

Vagrant.configure("2") do |config|

    config.vm.provider :libvirt do |domain|
        # Change the default allowed number of interfaces from 8 to 52
        domain.nic_adapter_count = 52
        # Change the MGMT network subnet and its default name
        domain.management_network_name = "clos_fabric_mgmt_network"
        domain.management_network_address = "172.16.100.0/24"

  end

################################
###### mgmt-server config ######
################################

config.vm.define "mgmt-server" do |device|
    device.vm.hostname = "mgmt-server"
    device.vm.box = SERVER_OS
    device.vm.synced_folder ".", "/vagrant", disabled: true

    # VM settings
    device.vm.provider :libvirt do |domain|
        domain.memory = 4096
        domain.cpus = 4
    end

    # No data plane links

    device.vm.provision "shell", inline: $mgmt_server_script
  end

####################################
########## spine01 config ##########
####################################

  config.vm.define "spine01" do |device|
    device.vm.box = SWITCH_OS
    device.vm.box_version = SWITCH_VERSION
    device.vm.synced_folder ".", "/vagrant", disabled: true
    device.vm.hostname = "spine01"

    # VM settings
    device.vm.provider :libvirt do |domain|
        domain.memory = 768
        domain.cpus = 1
    end

    # Link spine01 swp1  ----> leaf01 swp1
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.1",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.2",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "swp1",
      auto_config: false

    # Link spine01 swp2  ----> leaf02 swp1
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.3",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.4",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "swp2",
      auto_config: false

    # Link spine01 swp3  ----> leaf03 swp1
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.5",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.6",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "swp3",
      auto_config: false

    # Link spine01 swp4  ----> leaf04 swp1
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.7",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.8",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "swp4",
      auto_config: false

    # Call script + provide values for its variables
    device.vm.provision "shell", inline: $switches_script, :args => ["spine01", "4"]

  end


####################################
########## spine02 config ##########
####################################

config.vm.define "spine02" do |device|
    device.vm.box = SWITCH_OS
    device.vm.box_version = SWITCH_VERSION
    device.vm.synced_folder ".", "/vagrant", disabled: true
    device.vm.hostname = "spine02"

    # VM settings
    device.vm.provider :libvirt do |domain|
        domain.memory = 768
        domain.cpus = 1
    end

    # Link spine02 swp1  ----> leaf01 swp2
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.9",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.10",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "swp1",
      auto_config: false

    # Link spine02 swp2  ----> leaf02 swp2
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.11",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.12",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "swp2",
      auto_config: false

    # Link spine02 swp3  ----> leaf03 swp2
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.13",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.14",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "swp3",
      auto_config: false

    # Link spine02 swp4  ----> leaf04 swp2
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.15",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.16",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "swp4",
      auto_config: false


    device.vm.provision "shell", inline: $switches_script, :args => ["spine02", "4"]

  end


####################################
########## leaf01 config ##########
####################################

config.vm.define "leaf01" do |device|
    device.vm.box = SWITCH_OS
    device.vm.box_version = SWITCH_VERSION
    device.vm.synced_folder ".", "/vagrant", disabled: true
    device.vm.hostname = "leaf01"

    # VM settings
    device.vm.provider :libvirt do |domain|
        domain.memory = 768
        domain.cpus = 1
    end

    # Link leaf01 swp1  ----> spine01 swp1
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.2",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.1",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "swp1",
      auto_config: false

    # Link leaf01 swp2  ----> spine02 swp1
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.10",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.9",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "swp2",
      auto_config: false

    # Link leaf01 swp3  ----> server01 eth1
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.18",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.17",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "swp3",
      auto_config: false


    device.vm.provision "shell", inline: $switches_script, :args => ["leaf01", "3"]

  end




####################################
########## leaf02 config ##########
####################################

config.vm.define "leaf02" do |device|
    device.vm.box = SWITCH_OS
    device.vm.box_version = SWITCH_VERSION
    device.vm.synced_folder ".", "/vagrant", disabled: true
    device.vm.hostname = "leaf02"

    # VM settings
    device.vm.provider :libvirt do |domain|
        domain.memory = 768
        domain.cpus = 1
    end

    # Link leaf02 swp1  ----> spine01 swp2
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.4",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.3",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "swp1",
      auto_config: false

    # Link leaf02 swp2  ----> spine02 swp2
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.12",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.11",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "swp2",
      auto_config: false


    device.vm.provision "shell", inline: $switches_script, :args => ["leaf02", "2"]

  end



####################################
########## leaf03 config ##########
####################################

config.vm.define "leaf03" do |device|
    device.vm.box = SWITCH_OS
    device.vm.box_version = SWITCH_VERSION
    device.vm.synced_folder ".", "/vagrant", disabled: true
    device.vm.hostname = "leaf03"

    # VM settings
    device.vm.provider :libvirt do |domain|
        domain.memory = 768
        domain.cpus = 1
    end

    # Link leaf03 swp1  ----> spine01 swp3
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.6",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.5",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "swp1",
      auto_config: false

    # Link leaf03 swp2  ----> spine02 swp3
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.14",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.13",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "swp2",
      auto_config: false


    device.vm.provision "shell", inline: $switches_script, :args => ["leaf03", "2"]

  end

####################################
########## leaf04 config ##########
####################################

config.vm.define "leaf04" do |device|
    device.vm.box = SWITCH_OS
    device.vm.box_version = SWITCH_VERSION
    device.vm.synced_folder ".", "/vagrant", disabled: true
    device.vm.hostname = "leaf04"

    # VM settings
    device.vm.provider :libvirt do |domain|
        domain.memory = 768
        domain.cpus = 1
    end

    # Link leaf04 swp1  ----> spine01 swp4
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.8",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.7",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "swp1",
      auto_config: false

    # Link leaf04 swp2  ----> spine02 swp4
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.16",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.15",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "swp2",
      auto_config: false

    # Link leaf04 swp3  ----> server04 eth1
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.20",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.19",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "swp3",
      auto_config: false


    device.vm.provision "shell", inline: $switches_script, :args => ["leaf04", "3"]

  end


####################################
########## server01 config ##########
####################################


config.vm.define "server01" do |device|
    device.vm.hostname = "server01"
    device.vm.box = SERVER_OS
    device.vm.synced_folder ".", "/vagrant", disabled: true

    # VM settings
    device.vm.provider :libvirt do |domain|
        domain.memory = 768
        domain.cpus = 1
    end

    # Link server01 eth1  ----> leaf01 swp3
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.17",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.18",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "eth1",
      auto_config: false

      device.vm.provision "shell", inline: $servers_script
  end


####################################
########## server04 config ##########
####################################


config.vm.define "server04" do |device|
    device.vm.hostname = "server04"
    device.vm.box = SERVER_OS
    device.vm.synced_folder ".", "/vagrant", disabled: true

    # VM settings
    device.vm.provider :libvirt do |domain|
        domain.memory = 768
        domain.cpus = 1
    end

    # Link server01 eth1  ----> leaf04 swp3
    device.vm.network :private_network,
      :libvirt__tunnel_type => "udp",
      :libvirt__tunnel_local_ip => "127.0.100.19",
      :libvirt__tunnel_local_port => "9999",
      :libvirt__tunnel_ip => "127.0.100.20",
      :libvirt__tunnel_port => "9999",
      :libvirt__iface_name => "eth1",
      auto_config: false

      device.vm.provision "shell", inline: $servers_script
  end



end

Running ‘vagrant up’

Time to bring up the topology. Once we have our Vagranfile completed, we go inside the directory where the file is and run:

        
        
        
    
lab@lab-HP-Z620-Workstation:~/NetworkAuto/test_libvirt_tunnels$ vagrant up
Bringing machine 'mgmt-server' up with 'libvirt' provider...
Bringing machine 'spine01' up with 'libvirt' provider...
Bringing machine 'spine02' up with 'libvirt' provider...
Bringing machine 'leaf01' up with 'libvirt' provider...
Bringing machine 'leaf02' up with 'libvirt' provider...
Bringing machine 'leaf03' up with 'libvirt' provider...
Bringing machine 'leaf04' up with 'libvirt' provider...
Bringing machine 'server01' up with 'libvirt' provider...
Bringing machine 'server04' up with 'libvirt' provider...
...output trimmed...

Let’s check the status after the ‘vagrant up’ command finished:

        
        
        
    
lab@lab-HP-Z620-Workstation:~/NetworkAuto/test_libvirt_tunnels$ vagrant status
Current machine states:

mgmt-server               running (libvirt)
spine01                   running (libvirt)
spine02                   running (libvirt)
leaf01                    running (libvirt)
leaf02                    running (libvirt)
leaf03                    running (libvirt)
leaf04                    running (libvirt)
server01                  running (libvirt)
server04                  running (libvirt)

This environment represents multiple VMs. The VMs are all listed
above with their current state. For more information about a specific
VM, run `vagrant status NAME`.

Ok, looking good, it seems all VMs are up and running. Let’s see if the devices got their MGMT IP via DHCP:

        
        
        
    
lab@lab-HP-Z620-Workstation:~/NetworkAuto/test_libvirt_tunnels$ virsh net-list
 Name                       State    Autostart   Persistent
-------------------------------------------------------------
 clos_fabric_mgmt_network   active   no          yes
 default                    active   yes         yes

lab@lab-HP-Z620-Workstation:~/NetworkAuto/test_libvirt_tunnels$ virsh net-dhcp-leases clos_fabric_mgmt_network
 Expiry Time           MAC address         Protocol   IP address          Hostname      Client ID or DUID
------------------------------------------------------------------------------------------------------------
 2022-07-23 08:23:10   52:54:00:32:b8:46   ipv4       172.16.100.183/24   mgmt-server   ...output trimmed...
 2022-07-23 08:23:26   52:54:00:5e:59:fd   ipv4       172.16.100.59/24    leaf03        -
 2022-07-23 08:23:27   52:54:00:62:24:7c   ipv4       172.16.100.47/24    leaf02        -
 2022-07-23 08:23:27   52:54:00:80:ed:99   ipv4       172.16.100.159/24   spine01       -
 2022-07-23 08:23:29   52:54:00:84:d2:b9   ipv4       172.16.100.18/24    leaf04        -
 2022-07-23 08:23:20   52:54:00:9d:2a:3c   ipv4       172.16.100.132/24   server01      ...output trimmed...
 2022-07-23 08:23:27   52:54:00:c3:fa:1a   ipv4       172.16.100.112/24   leaf01        -
 2022-07-23 08:23:27   52:54:00:e2:b4:67   ipv4       172.16.100.50/24    spine02       -
 2022-07-23 08:23:20   52:54:00:ef:9b:e8   ipv4       172.16.100.11/24    server04      ...output trimmed...

Great, time for the final test, LLDP outputs:

        
        
        
    
lab@lab-HP-Z620-Workstation:~/NetworkAuto/test_libvirt_tunnels$ vagrant ssh spine01 -c "sudo net show lldp"

LocalPort  Speed  Mode     RemoteHost  RemotePort
---------  -----  -------  ----------  ----------
swp1       1G     Default  leaf01      swp1
swp2       1G     Default  leaf02      swp1
swp3       1G     Default  leaf03      swp1
swp4       1G     Default  leaf04      swp1
Connection to 172.16.100.159 closed.
lab@lab-HP-Z620-Workstation:~/NetworkAuto/test_libvirt_tunnels$ vagrant ssh spine02 -c "sudo net show lldp"

LocalPort  Speed  Mode     RemoteHost  RemotePort
---------  -----  -------  ----------  ----------
swp1       1G     Default  leaf01      swp2
swp2       1G     Default  leaf02      swp2
swp3       1G     Default  leaf03      swp2
swp4       1G     Default  leaf04      swp2
Connection to 172.16.100.50 closed.
lab@lab-HP-Z620-Workstation:~/NetworkAuto/test_libvirt_tunnels$ vagrant ssh server01 -c "sudo lldpcli show nei summary"
-------------------------------------------------------------------------------
LLDP neighbors:
-------------------------------------------------------------------------------
Interface:    eth1, via: LLDP
  Chassis:
    ChassisID:    mac 52:54:00:c3:fa:1a
    SysName:      leaf01
  Port:
    PortID:       ifname swp3
    PortDescr:    swp3
    TTL:          120
-------------------------------------------------------------------------------
Connection to 172.16.100.132 closed.
lab@lab-HP-Z620-Workstation:~/NetworkAuto/test_libvirt_tunnels$ vagrant ssh server04 -c "sudo lldpcli show nei summary"
-------------------------------------------------------------------------------
LLDP neighbors:
-------------------------------------------------------------------------------
Interface:    eth1, via: LLDP
  Chassis:
    ChassisID:    mac 52:54:00:84:d2:b9
    SysName:      leaf04
  Port:
    PortID:       ifname swp3
    PortDescr:    swp3
    TTL:          120
-------------------------------------------------------------------------------
Connection to 172.16.100.11 closed.
lab@lab-HP-Z620-Workstation:~/NetworkAuto/test_libvirt_tunnels$

As we can see from the LLDP outputs above, our topology is up and working as per our diagram. In terms of data plane, we don’t have anything configured yet, but we can manage all devices from either our host machine or using the mgmt-server VM.

In conclusion, we’ve reached our goal. We’ve got a topology ready to start running our various automation scripts or to test all the new fancy technologies.