Someone using my netsim-tools sent me an intriguing question: “Would it be possible to get network topology graphs out of the tool?”

I did something similar a long while ago for a simple network automation project (and numerous networking engineers built really interesting stuff while attending the Building Network Automation Solutions course), so it seemed like a no-brainer. As always, things aren’t as easy as they look.

Initial implementation of Noël Boulene’s automated provisioning of NSX-T distributed firewall rules changed NSX-T firewall configuration based on Terraform configuration files. To make the deployment fully automated he went a step further and added a full-blown CI/CD pipeline using GitHub Actions and Terraform Cloud.

Not everyone is as lucky as Noël – developers in his organization already use GitHub and Terraform Cloud, making his choices totally frictionless.

In December 2020, I got sick-and-tired of handcrafting Vagrantfiles and decided to write a tool that would, given a target networking lab topology in a text file, produce the corresponding Vagrantfile for my favorite environment (libvirt on Ubuntu). Nine months later, that idea turned into a pretty comprehensive tool targeting networking engineers who like to work with CLI and text-based configuration files. If you happen to be of the GUI/mouse persuasion, please stop reading; this tool is not for you.

During those nine months, I slowly addressed most of the challenges I always had creating networking labs. Here’s how I would typically approach testing a novel technology or software feature:

Noël Boulene decided to automate provisioning of NSX-T distributed firewall rules as part of his Building Network Automation Solutions hands-on work.

What makes his solution even more interesting is the choice of automation tool: instead of using the universal automation hammer (aka Ansible) he used Terraform, a much better choice if you want to automate service provisioning, and you happen to be using vendors that invested time into writing Terraform provisioners.

One of the major challenges of using netsim-tools was the installation process – pull the code from GitHub, install the prerequisites, set up search paths… I knew how to fix it (turn the whole thing into a Python package) but I was always too busy to open that enormous can of worms.

That omission got fixed in summer 2021; netsim-tools is now available on PyPI and installed with pip3 install netsim-tools.

Two interesting container images were released in June/July 2021:

• Michael Kashin managed to package Cumulus VX into a container image (more details).
• Roman Dodin managed to persuade Nokia to release SR Linux as a container.

Both images can be downloaded with no strings attached (two major wins for the good guys) and are supported with the latest release of netsim-tools:

netsim-tools release 0.7 is published, bringing you the following goodies (including stuff published a week ago as release 0.6.3):

• Cumulus VX support on libvirt and virtualbox.
• EIGRP configuration module
• BGP IPv6 address family
• Controlled BGP community propagation

Other changes include:

One of the students in our Building Network Automation Solutions online course asked an interesting question:

I’m building an IPsec multi-vendor automation solution and am now facing the challenge of vendor-specific parameter names. For example, to select the AES-128 algorithm, Juniper uses ‌aes-128-cbc, Arista aes128, and Checkpoint AES-128.

I guess I need a kind of Rosetta stone to convert the IKE/IPSEC parameters from a standard parameter to a vendor-specific one. Should I do that directly in the Jinja2 template, or in the Ansible playbook calling the template?

Both options are awkward. It would be best to have a lookup table mapping parameter values from the data model into vendor-specific keywords, for example:

Last week we pushed out netsim-tools release 0.6.2. It’s a maintenance release, so mostly full of bug fixes apart from awesome contributions by Leo Kirchner who

• Made vSRX 3.0 work on AMD CPU (warning: totally unsupported).
• Figured out how to use vagrant mutate to use virtualbox version of Cisco Nexus 9300v Vagrant box with libvirt

Other bug fixes include:

• Numerous fixes in Ansible installation playbook
• LLDP on all vSRX interfaces as part of initial configuration
• Changes in FRR configuration process to use bash or vtysh as needed
• connect.sh executing inline commands with docker exec

I love hearing real-life “how did I start my automation journey” stories. Here’s what one of ipSpace.net subscribers sent me:

• Make peace with your network engineering soul and mind and open up to the possibility that the world has moved on to something else when it comes to consuming apps and software. Back in 2017, this was very hard on me :)

TL&DR: If you’d like to see how easy it is to deploy a full-blown OSPF+BGP network with netsim-tools together with Containerlab and FRRouting, check out this Katacoda scenario.

What is Katacoda? An awesome environment that allows content authors to create scenarios running on Linux VMs accessible through a web browser. I can only hope they’ll fix the quirks and keep going – I have so many ideas what could be done with it.

Why FRR? Not too long ago Jeroen van Bemmel sent me a link to a simple Katacoda scenario he created to demonstrate how to set up netsim-tools and containerlab. His scenario got the tools installed and set up, but couldn’t create a running network as there are almost no usable Network OS images on Docker Hub (that is accessible from within Katacoda) – the only image I could find was FRR.

TL&DR: If you want to test BGP, OSPF, IS-IS, or SR-MPLS in a virtual lab, you might build the lab faster with netsim-tools release 0.6.

In the netsim-tools release 0.6 I focused on adding routing protocol functionality:

• IS-IS on Cisco IOS/IOS XE, Cisco NX-OS, Arista EOS, FRR, and Junos.
• BGP on the same set of platforms, including support for multiple autonomous systems, EBGP, IBGP full mesh, IBGP with route reflectors, next-hop-self control, and BGP/IGP interaction.
• Segment Routing with MPLS on Cisco IOS XE and Arista EOS.

You’ll also get:

I know the title sounds like a buzzword-bingo-winning clickbait, but it’s true. Adrian Giacometti decided to merge the topics of two ipSpace.net online courses and automated deployment of AWS security rules using Terraform within GitLab CI pipeline, with Slack messages serving as manual checks and approvals.

Not only did he do a great job mastering- and gluing together so many diverse bits and pieces, he also documented the solution and published the source code:

• Part 1: Cloud & Network automation challenge: Deploy Security Rules in a DevOps/GitOps world with AWS, Terraform, GitLab CI, Slack, and Python (special guest FastAPI)
• Part 2: AWS, Terraform and FastAPI
• Part 3: GitLab CI, Slack, and Python
• Source code: aegiacometti/devops_cloud_challenge · GitLab

Want to build something similar? Join our Network Automation and/or Public Cloud course and get started. Need something similar in your environment? Adrian is an independent consultant and ready to work on your projects.

The reader asking about infrastructure-as-code in public cloud deployments also wondered whether he has any chance at mastering on-premises network automation due to lack of programming skills.

I am starting to get concerned about not knowing automation, IaC, or any programming language. I didn’t go to college, like a lot of my peers did, and they have some background in programming.

First of all, thanks a million to everyone needs to become a programmer hipsters for thoroughly confusing people. Now for a tiny bit of reality.

TL&DR: If you happen to like working with containers, you could use netsim-tools release 0.5 to provision your container-based Arista EOS labs.

Why does it matter? Lab setup is blindingly fast, and it’s easier to integrate your network devices with other containers, not to mention the crazy idea of running your network automation CI pipeline on Gitlab CPU cycles. Also, you could use the same netsim-tools topology file and provisioning scripts to set up container-based or VM-based lab.

What is containerlab? A cool project that builds realistic virtual network topologies with containers. More details…