ansible_automation_EX457

This guide will walk through setting up GNS3 on and Ubuntu 20.04 host in GCP

Create Ubuntu 20.04 host and enable nested virtualization on GCP

Create a boot disk from a public image

gcloud compute disks create nested-vm-disk --type=pd-standard --zone=northamerica-northeast1-c --image-family=ubuntu-2004-lts --image-project=ubuntu-os-cloud

Create a custom image from the boot disk

gcloud compute images create nested-ubuntu-2004 --source-disk nested-vm-disk --source-disk-zone northamerica-northeast1-c --licenses "https://www.googleapis.com/compute/v1/projects/vm-options/global/licenses/enable-vmx"
gcloud compute disks delete nested-vm-disk

Create a virtual machine in Google Compute Engine

gcloud compute instances create gns3host --zone northamerica-northeast1-c --min-cpu-platform "Intel Cascade Lake" --image nested-ubuntu-2004 --machine-type=n2-standard-2 --boot-disk-size=300GB --boot-disk-type=pd-standard

Open ports used to connect to GNS3

gcloud compute firewall-rules create gns3-inbound --description="open up the ports used by gns3" --direction=INGRESS --priority=1000 --network=default --action=ALLOW --rules=tcp:3080,tcp:5000-10000 --source-ranges=0.0.0.0/0

Install GNS3 on Ubuntu host

Update and upgrade all the installed packages

sudo apt update && sudo apt upgrade -y

Add gns3 repo ant install the server

sudo add-apt-repository ppa:gns3/ppa -y

Add IOU (Cisco IOS on Unix) support

sudo dpkg --add-architecture i386      

Remove docker if already installed

sudo apt remove docker docker.io -y

Add docker gpg key and repo

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
sudo add-apt-repository \
"deb [arch=amd64] https://download.docker.com/linux/ubuntu \
   $(lsb_release -cs) stable"

Install all required software

sudo apt update
sudo apt install gns3-server gns3-iou qemu-kvm docker-ce net-tools uml-utilities iptables-persistent -y

Check KVM

kvm-ok

Add gns3 user and to the required groups

sudo useradd gns3 --create-home
sudo passwd gns3
sudo usermod -aG ubridge,libvirt,kvm,docker gns3

Set up GNS3 service

sudo touch /etc/systemd/system/gns3.service
sudo vi /etc/systemd/system/gns3.service

Save this file

[Unit]
Description=GNS3 server
Wants=network-online.target
After=network.target network-online.target

[Service]
Type=forking
User=gns3
Group=gns3
PermissionsStartOnly=true
ExecStartPre=/bin/mkdir -p /var/log/gns3 /var/run/gns3
ExecStartPre=/bin/chown -R gns3:gns3 /var/log/gns3 /var/run/gns3
ExecStart=/usr/bin/gns3server --log /var/log/gns3/gns3.log \
 --pid /var/run/gns3/gns3.pid --daemon
ExecReload=/bin/kill -s HUP $MAINPID
Restart=on-abort
PIDFile=/var/run/gns3/gns3.pid

[Install]
WantedBy=multi-user.target

Set file permissions and configure GNS3 service to start on boot

sudo chown root /etc/systemd/system/gns3.service
sudo systemctl enable gns3.service

Set firewall rules to allow connection from remote dev environment

sudo ufw allow 3080/tcp
sudo ufw allow 5000:10000/tcp

Set up tap interface to allow communication from Ubuntu host to GNS3 objects via Cloud

sudo modprobe tun
sudo tunctl -t tap0
sudo ifconfig tap0 10.0.0.1 netmask 255.255.255.0 up
sudo ifconfig

Set NAT forwarding

sudo iptables -t nat -A POSTROUTING -o ens4 -j MASQUERADE
sudo iptables -A FORWARD -i tap0 -j ACCEPT
sudo iptables -t nat -vxnL
sudo tcpdump -i tap0  -s 1500
sudo tcpdump -i ens4  -s 1500 port not 22

Install Python 3.10, Pip and Ansible

sudo apt install software-properties-common -y
sudo add-apt-repository ppa:deadsnakes/ppa
sudo apt install python3.10
sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.8 1
sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.10 2
sudo update-alternatives --config python3
python3 --version
sudo apt install python3-pip
pip --version
pip install ansible paramiko ansible-pylibssh netaddr
ansible --version

Configure GNS3

Now you can log into GNS3 and configure the installation

1. Go to Edit > Preferences and then click on Server
2. Make sure Enable local server is unchecked
3. Under Remote main server enter the ephemeral public IP address of you GCE instance
4. All other settings on this page can stay default
5. Click on IOS on Unix and enter the IOU license
6. Configure IOU device templates under IOU devices
7. Click OK Next create a new project and add routers, a switch and a cloud SSH to each router inside GNS3 to get SSH keys stored

ssh -o KexAlgorithms=+diffie-hellman-group-exchange-sha1 -c aes256-cbc developer@10.0.0.10

Basic config for IOS routers (developer/C1sco12345)

conf t
hostname R1
int e1/3
ip address 10.0.0.10 255.255.255.0
no shut
ip domain-name gns3.local
crypto key gen rsa mod 1024
username developer priv 15 secret C1sco12345
enable secret C1sco12345
line vty 0 4
login local
transport input ssh
exit
exit
wr mem

Basic config for IOS-XE routers (developer/C1sco12345)

conf t
no service call-home 
no call-home
hostname R1
int e1/3
ip address 10.0.0.10 255.255.255.0
no shut
ip domain-name gns3.local
crypto key gen rsa mod 1024
username developer priv 15 secret C1sco12345
enable secret C1sco12345
restconf
ip http secure-server
ip http authentication local
line vty 0 4
login local
transport input ssh
exit
exit
wr mem

Basic config for switches (developer/C1sco12345)

conf t
hostname S1
vlan 100
exit
int vlan 100
ip address 10.0.0.20 255.255.255.0
no shut
int range e1/0 - 3
switchport access vlan 100
ip domain-name gns3.local
crypto key gen rsa mod 1024
username developer priv 15 secret C1sco12345
enable secret C1sco12345
line vty 0 4
login local
transport input ssh
exit
exit
wr mem

Basic config for vyos (vyos/vyos)

First you must install the VyOS image

1. Create template with VyOS gns3 appliance and VyOS iso
2. After booting run 'install image'
3. Run through wizard selecting the defaults
4. When installation prompts which file to choose for config boot, choose second option: /opt/vyatta/etc/config.boot.default
5. When installation finishes poweroff
6. Note location of GNS3 project folder
7. Exit GNS3
8. ssh to host server and cd to project folder
9. su gns3
10. qemu-img commit virtioa.qcow2
11. cp virtioa.qcow2 /home/gns3/GNS3/images/QEMU/vyos.qcow2
12. chmod 700 /home/gns3/GNS3/images/QEMU/vyos.qcow2
13. Open GNS3 back up and locate the VyOS template
14. Edit HDD tab to set Disk image to vyos.qcow2 and Disk interface to virtio
15. Edit CD/DVD to remove the iso

conf
set system host-name V1
set system domain-name gns3.local
set interfaces ethernet eth6 address 10.0.0.14/24
set interfaces ethernet eth0 address 10.1.3.2/30
set interfaces ethernet eth1 address 10.1.5.1/30
set service ssh port '22'
commit
save

Basic config for arista (admin)

enable
zerotouch cancel
enable
conf t
hostname A1
int management 1
ip address 10.0.0.30/24
no shut
exit
management api http-commands
protocol https port 443
protocol http port 80
no shutdown
exit
ip route 0.0.0.0/0 10.0.0.1
wr
exit