[kcdc 2022] reduce system fragility with terraform

Speaker: Scott McAllister @stmcallister

For more, see the table of contents


  • Problem: onboarding same thing dozens of time
  • Infrastructure as code – fast to configure/scale, consistent, reduce errors, self documenting
  • AWS CloudFormation, Azure ARM, Terraform and Pulumi in this space. (Pulumi has been rising and is 2)
  • Terraform is declarative, Pulumi is imperative; use existing programming language


  • Declarative
  • Open source – most people use this oer enterprise
  • HCL – Hashicorp configuraton language
  • Manage infrastructure – build, change, version, single source of truth
  • No longer use UI; Terraform will overwrite changes
  • Hashicorp maintains Terraform engine


  • Hashicorp maintains a few large providers (ex: AWS)
  • Everything else run by community or other companies
  • Doc example https://registry.terraform.io/providers/PagerDuty/pagerduty/latest/docs


  • Practitioner writes infrastructure as code
  • init – takes definitions in directory, downloads providers
  • plan – want to do this so not billed before confirm
  • apply – changes pushed to environments. Runs plan first. Type ”yes” to confirm or use auto approve flag
  • destroy – wipe out everything have
  • Terraform state has data about config – ex; generated id. In JSON format

Good practices

  • Name service what is providing. Ex: ”Checkout API”
  • Version control system
  • Code review
  • Automated testing
  • Put tokens in environment variable rather than hard coding in script

HCL blocks

  • resource – you are going to manage it, create if not present, etc. Convention: providerName_endpoint. Then unique id – like a variable name within terraform. Ex: resource ”pagerduty_user” ”lisa”, Reference as pageruty_user.lisa.id
  • data – like a query. Get data about something that already exists in system. Reference as data.provider_user.id
  • required_providers – downloads binaries when run tf init. Recommend locking into a version or at least a major version

Data types

  • strings
  • numbers
  • [list, of, data]
  • { a: b, c:d } (complex object)

Can play for free: https://github.com/PagerDuty-Samples/pd-populate-dev-account


  • Can find syntax and logic errors in plan. Depends on provider
  • Libraries to convert to HCL. Ex: LDAP to HCL

My take

This served as both a good overview and a good review of the basics. I like that it had a lot of code in it. I’m taking the Terraform cert this month so nice timing for me to attend this talk. I really appreciate the link/API to play for free. Testing on AWS is scary :).

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