Task 1.1: Explain what IaC is

• ADescribe the infrastructure in configuration files that a tool applies through APIs

  Correct

  IaC means managing infrastructure with configuration files rather than through a graphical console, so the files, not people, drive the changes.

• BRecord a screen video of each console session so the steps can be repeated exactly

  Incorrect

  A recording still documents a manual process; a person has to repeat every click, which is what IaC replaces.

• CTake a snapshot image of each finished server and restore that image in every new environment

  Incorrect

  Images capture one machine's disk. They do not describe or manage the networks, DNS and other infrastructure around it.

• DMove the wiki page into version control so that every edit to the console steps gets a review

  Incorrect

  Versioning a manual procedure helps review, but the infrastructure is still built by hand. IaC versions files that a tool executes.

Infrastructure as code replaces manual, console-driven provisioning with configuration files that a tool such as Terraform applies through each platform's API, safely and repeatably.

• AThe configuration lists each API call in sequence, and Terraform runs them from top to bottom

  Incorrect

  That is the procedural model of a script. Terraform does not run blocks as a sequence of commands.

• BThe configuration is compiled into a shell script that the cloud provider runs on its side

  Incorrect

  Terraform does not produce scripts for the provider. Its providers call the platform APIs directly.

• CThe configuration describes only what to change since the last run, like a migration file

  Incorrect

  A Terraform configuration describes the whole desired infrastructure, not a delta; Terraform calculates the changes itself.

• DThe configuration states the end result; Terraform works out the API calls and their order

  Correct

  Terraform's language is declarative. You describe the desired end state and Terraform handles the underlying logic instead of step-by-step instructions.

Declarative configuration describes what should exist and leaves the steps to Terraform; a script encodes the steps themselves.

• ATerraform reads files in alphabetical order, so the VPC block must move into main.tf above the subnet

  Incorrect

  Terraform loads all .tf files in the directory together as one configuration. File names and block order do not set the creation order.

• BTerraform orders the work from the references, so the VPC is created before its subnet

  Correct

  Terraform builds a resource graph to determine dependencies; the subnet's reference to the VPC places it after the VPC whatever the file order.

• CTerraform creates resources in the order their blocks appear, so the reviewer must reorder the blocks

  Incorrect

  Block order has no effect on execution in a declarative configuration; the graph does.

• DTerraform creates every resource at the same time and retries the subnet until the VPC exists

  Incorrect

  Terraform does run independent resources in parallel, but it waits for dependencies instead of retrying blindly.

Order in files means nothing to Terraform. References between resources become edges in the dependency graph, and Terraform walks that graph, running independent nodes in parallel.

• AEdit the storage value in the configuration, review the plan and apply

  Correct

  Terraform manages infrastructure throughout its lifecycle with the same workflow, so later changes go through the configuration as well.

• BWrite a second configuration that contains only the storage change for this cluster

  Incorrect

  A second configuration for one change would split management of the same object.

• CChange the storage in the console and add a note to the repository

  Incorrect

  A console change leaves the configuration describing the old value.

• DRun terraform init with the new storage value as an option

  Incorrect

  init prepares the working directory; it does not take resource values.

IaC covers the whole life of the infrastructure. Every change, not only the first build, goes through the files and the plan.

• APassing YAML files to terraform apply with a -config option

  Incorrect

  Terraform has no YAML configuration format or -config option.

• BWriting the definitions directly into terraform.tfstate before running apply

  Incorrect

  State records what Terraform manages; it is never a way to declare new infrastructure.

• CWriting the configuration in JSON syntax in files that end in .tf.json

  Correct

  Terraform reads configuration in its native syntax (.tf) and in a JSON-based variant (.tf.json) meant for files generated by programs.

• DSaving the definitions as a plan file and applying that plan

  Incorrect

  Plan files are produced by terraform plan, not written by other tools.

Configuration is plain text in either HCL or JSON, so both people and programs can produce it.

• ALogic is allowed only inside provisioners, which run shell commands

  Incorrect

  Provisioners run commands on resources; configuration logic lives in expressions.

• BIt stays declarative but has variables, conditionals, for expressions and functions

  Correct

  Terraform expressions include conditionals, for expressions and built-in functions, which compute values while the configuration still describes an end state.

• CTerraform has an imperative mode that is switched on with a command-line flag

  Incorrect

  There is no imperative mode; Terraform is always declarative.

• DSeparate copies are the only option, because variables cannot change which resources exist

  Incorrect

  Input variables exist precisely to customize a configuration without copying it.

Declarative does not mean static. Expressions compute the values of the end state you describe.

• ADNS records in a hosted DNS service

  Incorrect

  DNS records are a documented example of a high-level component Terraform manages.

• BListener rules on a cloud load balancer

  Incorrect

  Networking components such as load balancers are managed through the cloud provider's API.

• CObject storage buckets and their access policies

  Incorrect

  Storage is one of the low-level components Terraform manages through a provider.

• DPhysical patch cables between two switches

  Correct

  Terraform manages infrastructure through APIs. A physical cable has no API, so no provider can create or change it.

The limit of IaC with Terraform is the API. Something that cannot be driven through an API cannot be described in configuration and applied.