Whilst it is not only for network automation it seems to be everywhere when you are looking for resources and as previously mentioned if it's not Python then it's generally Ansible which is written also in Python.
I think I have mentioned this already but during the "Learn a programming language" section I chose Golang over Python for reasons around my company is developing in Go so that was a good reason for me to learn but if that was not the case then Python would have taken that time.
- Readability and ease of use - It seems that Python seems just makes sense. There don't seem to be the requirements around `{}` in the code to start and end blocks. Couple this with a strong IDE like VS Code you have a pretty easy start when wanting to run some python code.
Pycharm might be another IDE worth mentioning here.
- Libraries - The extensibility of Python is the real gold mine here, I mentioned before that this is not just for Network Automation but in fact, there are libraries plenty for all sorts of devices and configurations. You can see the vast amount here [PyPi](https://pypi.python.org/pypi)
When you want to download the library to your workstation, then you use a tool called `pip` to connect to PyPI and download it locally. Network vendors such as Cisco, Juniper, and Arista developed libraries to facilitate access to their devices.
- Powerful & Efficient - Remember during the Go days I went through the "Hello World" scenario and we went through I think 6 lines of code? In Python it is
I think it's important to note that it's possible that several years back there were scripts that might have interacted with your network devices to maybe automate the backup of configuration or to gather logs and other insights into your devices. The automation we are talking about here is a little different and that's because the overall networking landscape has also changed to suit this way of thinking better and enabled more automation.
- Software-Defined Network - SDN Controllers take the responsibility of delivering the control plane configuration to all devices on the network, meaning just a single point of contact for any network changes, no longer having to telnet or SSH into every device and also relying on humans to do this which has a repeatable chance of failure or misconfiguration.
- High-Level Orchestration - Go up a level from those SDN controllers and this allows for orchestration of service levels then there is the integration of this orchestration layer into your platforms of choice, VMware, Kubernetes, Public Clouds etc.
- Policy-based management - What do you want to have? What is the desired state? You describe this and the system has all the details on how to figure it out to become the desired state.
I wanted to make it possible for us to look at some of the tooling pre-mentioned but also get hands-on and learn how to automate the configuration of our networks.
We will build our lab out using [Eve-ng](https://www.eve-ng.net/) as mentioned before you can use a physical device but to be honest a virtual environment means that we can have a sandbox environment to test many different scenarios. Plus being able to play with different devices and topologies might be of interest.
For our walkthrough, we will be using VMware Workstation as I have a license via my vExpert but you can equally use VMware Player or any of the other options mentioned in the [documentation](https://www.eve-ng.net/index.php/documentation/installation/system-requirement/). Unfortunately we cannot use our previously used Virtual box!
Now we have our hypervisor software downloaded and installed, and we have the EVE-NG OVF downloaded. If you are using VMware Player please let me know if this process is the same.
When the import is complete increase the number of processors to 4 and the memory allocated to 8 GB. (This should be the case after import with the latest version if not then edit VM settings)
Also, make sure the Virtualise Intel VT-x/EPT or AMD-V/RVI checkbox is enabled. This option instructs the VMware workstation to pass the virtualisation flags to the guest OS (nested virtualisation) This was the issue I was having with GNS3 with Virtual Box even though my CPU allows this.
Sidenote & Rabbit hole: Remember I mentioned that this would not work with VirtualBox! Well yeah had the same issue with VMware Workstation and EVE-NG but it was not the fault of the virtualisation platform!
I have WSL2 running on my Windows Machine and this seems to remove the capability of being able to run anything nested inside of your environment. I am confused as to why the Ubuntu VM does run as it seems to take out the Intel VT-d virtualisation aspect of the CPU when using WSL2.
To resolve this we can run the following command on our Windows machine and reboot the system, note that whilst this is off then you will not be able to use WSL2.
The default username for the GUI is `admin` and the password is `eve` while the default username for SSH is `root` and the password is `eve` but this would have been changed if you changed during the setup.
