Infrastructure as Code with Terraform, including best practices and examples
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Azure DNS Private Resolver has a documented limit that reads like a feature: two DNS forwarding rulesets per outbound endpoint. The portal, however, behaves as though the limit is one. I had to try proving the documentation right, the portal wrong, and why you might actually want two rulesets on the same endpoint in the first place.
I build a lot of labs and demos in Azure, and I often start by creating resources manually in the portal. It's quick and easy to get something up and running. I am also keen to keep my Azure Lab environment costs as low as possible so I try to only run resources when I am using them. With a busy family life, three kids, a spaniel and a rather involved job, I don't have the time to be constantly building and tearing down environments so I use Terraform where I can to define the labs so I can spin them up and down as needed.
I have been working on a comprehensive approach to bringing network automation and documentation into a development style workflow. Rather than replacing the traditional ITSM approach to change management it moves infrastructure towards a CI/CD approach to releases with automation and baked in documentation.
In a recent blog post I wrote: "As network engineers we are used to the declarative model of configuration management and so this fits nicely into that mindset - you declare what you want and Terraform will make it so." But declaring what you want is only half the battle. The real challenge lies in how you structure that declaration to handle the messy reality of business requirements whilst maintaining the automation benefits that drew us to declarative tools in the first place.
There is an excellent Terraform provider for Netbox that allows you to manage your Netbox resources using Terraform. This is particularly useful for automating the management of network devices, IP addresses, and other resources in a consistent and repeatable manner. I have been working through the process of setting this up and have found it to be a powerful tool for a documentation first and a documentation as code approach to network management.