Nornir tasks are run against all or a subset of inventory members with the result formatted into a framework structured to show what was run against whom and the results. Tasks can be custom built python code or pre-built plugins that have been installed and imported.
The inventory is at the core of Nornir holding all the hosts that tasks will be run against and the variables that will be used by those tasks. Before any tasks can be run by Nornir the inventory has to be initialised.
If you have an understanding of Python and have been working with Ansible it is likely at some point you will get to the stage where you ask yourself ‘there has to be something better’. For network automation that better could well be Nornir.
Over the years I have built numerous IPsec VPNs on ASAs using crypto maps and an ACL for the interesting traffic. For a simple solution to join small sites with no need for routing these work great and keep the complexity down to a minimum. For more complex environments or cloud connectivity you are probably going to need to use VTIs, this post goes through the process of building VTI VPNs between an ASR and ASA.
This post explains how to configure EVE-NG as a DHCP server (isc-dhcp-server) assigning IPs to lab devices that are then dynamically NATed behind the primary EVE management IP address (iptables masquerade) to provide Internet breakout.
A trip down memory lane on how things have changed in labbing from using prehistoric switches bought on eBay through emulators that took longer to configure than the labs to the present day solutions that can programmatically build a multi-vendor lab in minutes. Kids today don’t know they are born…..
The 6th post in the ‘Automate Leaf and Spine Deployment’ series goes through the validation of the fabric once deployment has been completed. A desired state validation file is built from the contents of the variable files and compared against the devices actual state to determine whether the fabric and all the services that run on top of it comply.
The 5th post in the ‘Automate Leaf and Spine Deployment’ series goes through the deployment of the services that run on top of the fabric. These services are grouped into 3 categories, tenant, interface and routing. Services are configured only on the leaf and border switches, the spines have no need for them as they just route the VXLAN encapsulated packets with no knowledge or care of what is within them.
The 4th post in the ‘Automate Leaf and Spine Deployment’ series goes through the creation of the base and fabric config snippets and their deployment to devices. Loopbacks, NVE and intra-fabric interfaces are configured and both the underlay and overlay routing protocol peerings formed leaving the fabric in a state ready for services to be added.
The 3rd post in the ‘Automate Leaf and Spine Deployment’ series goes the through the variables from which the core fabric declaration is made and how this transposes into a dynamic inventory. This uses only the base and fabric roles to create the fabric ready for the service sub-roles (tenant, interface and route) to be deployed on top of the fabric at a later stage.
The 2nd post in the ‘Automate Leaf and Spine Deployment’ series describes process used for validating the variable files format and content. The idea behind this offline pre-validation is to catch any errors in the variable files before device configuration is attempted. Fail fast based on logic instead of failing halfway through a build. It wont catch everything but will eliminate a lot of the needless errors that would break a fabric build.
This series of posts will describe the process of deploying a NXOS Leaf and spine fabric in a declarative manner using Ansible. This came from my project for the IPSpace Building Network Automation Solutions course and was used in part when we were deploying leaf and spine fabrics in our Data Centers. I originally only planned to build tenants and do fabric validation but over time this has morphed into a full blown fabric deployment.