What is Terraform (Iac Tool) and How to Install Terraform ?



Infrastructure as code (IaC) tools allow you to manage infrastructure with configuration files rather than through a graphical user interface. IaC allows you to build, change, and manage your infrastructure in a safe, consistent, and repeatable way by defining resource configurations that you can version, reuse, and share.

Terraform is HashiCorp’s infrastructure as code tool. It lets you define resources and infrastructure in human-readable, declarative configuration files, and manages your infrastructure’s lifecycle. Using Terraform has several advantages over manually managing your infrastructure:

  • Terraform can manage infrastructure on multiple cloud platforms.

  • The human-readable configuration language helps you write infrastructure code quickly.

  • Terraform's state allows you to track resource changes throughout your deployments.

  • You can commit your configurations to version control to safely collaborate on infrastructure.

Manage any infrastructure

Terraform plugins called providers let Terraform interact with cloud platforms and other services via their application programming interfaces (APIs). HashiCorp and the Terraform community have written over 1,000 providers to manage resources on Amazon Web Services (AWS), Azure, Google Cloud Platform (GCP), Kubernetes, Helm, GitHub, Splunk, and DataDog, just to name a few. Find providers for many of the platforms and services you already use in the Terraform Registry. If you don't find the provider you're looking for, you can write your own.


Modules:

Modules are containers for multiple resources that are used together. A module consists of a collection of .tf and/or .tf.json files kept together in a directory.

Modules are the main way to package and reuse resource configurations with Terraform.


To deploy infrastructure with Terraform:

  • Scope - Identify the infrastructure for your project.

  • Author - Write the configuration for your infrastructure.

  • Initialize - Install the plugins Terraform needs to manage the infrastructure.

  • Plan - Preview the changes Terraform will make to match your configuration.

  • Apply - Make the planned changes.

Track your infrastructure

Terraform keeps track of your real infrastructure in a state file, which acts as a source of truth for your environment. Terraform uses the state file to determine the changes to make to your infrastructure so that it will match your configuration.



Steps to Install Terraform on macOS:

raghavendrakambhampati@RaghavendrasMBP ~ % brew tap hashicorp/tap
Updating Homebrew...
==> Auto-updated Homebrew!
Updated 2 taps (homebrew/core and homebrew/cask).
==> New Formulae
clang-format@11                      fnlfmt                               libsigrokdecode                      spdx-sbom-generator                  uuu
datafusion                           go-critic                            mdzk                                 twty
==> Updated Formulae
Updated 2335 formulae.
==> New Casks
azirevpn            betterdummy         breitbandmessung    codeql              inso                keycombiner         ppsspp              tev                 ultracopier
==> Updated Casks
Updated 487 casks.
==> Deleted Casks
anzeigenchef   archi          bearychat      blooo          breakaway      collabshot     cytoscape      eudic-es       fritzing       tuntap         videobox       zipcleaner

==> Tapping hashicorp/tap
Cloning into '/usr/local/Homebrew/Library/Taps/hashicorp/homebrew-tap'...
remote: Enumerating objects: 1627, done.
remote: Counting objects: 100% (381/381), done.
remote: Compressing objects: 100% (255/255), done.
remote: Total 1627 (delta 253), reused 218 (delta 126), pack-reused 1246
Receiving objects: 100% (1627/1627), 294.23 KiB | 3.06 MiB/s, done.
Resolving deltas: 100% (949/949), done.
Tapped 1 cask and 11 formulae (42 files, 415.8KB).
raghavendrakambhampati@RaghavendrasMBP ~ % brew install hashicorp/tap/terraform
==> Downloading https://releases.hashicorp.com/terraform/1.0.10/terraform_1.0.10_darwin_amd64.zip
######################################################################## 100.0%
==> Installing terraform from hashicorp/tap
🍺  /usr/local/Cellar/terraform/1.0.10: 3 files, 75.8MB, built in 6 seconds

To Verify the installation, run the below commands to validate:

raghavendrakambhampati@RaghavendrasMBP ~ % terraform -help
Usage: terraform [global options] <subcommand> [args]

The available commands for execution are listed below.
The primary workflow commands are given first, followed by
less common or more advanced commands.

Main commands:
  init          Prepare your working directory for other commands
  validate      Check whether the configuration is valid
  plan          Show changes required by the current configuration
  apply         Create or update infrastructure
  destroy       Destroy previously-created infrastructure

All other commands:
  console       Try Terraform expressions at an interactive command prompt
  fmt           Reformat your configuration in the standard style
  force-unlock  Release a stuck lock on the current workspace
  get           Install or upgrade remote Terraform modules
  graph         Generate a Graphviz graph of the steps in an operation
  import        Associate existing infrastructure with a Terraform resource
  login         Obtain and save credentials for a remote host
  logout        Remove locally-stored credentials for a remote host
  output        Show output values from your root module
  providers     Show the providers required for this configuration
  refresh       Update the state to match remote systems
  show          Show the current state or a saved plan
  state         Advanced state management
  taint         Mark a resource instance as not fully functional
  test          Experimental support for module integration testing
  untaint       Remove the 'tainted' state from a resource instance
  version       Show the current Terraform version
  workspace     Workspace management

Global options (use these before the subcommand, if any):
  -chdir=DIR    Switch to a different working directory before executing the
                given subcommand.
  -help         Show this help output, or the help for a specified subcommand.
  -version      An alias for the "version" subcommand.

raghavendrakambhampati@RaghavendrasMBP ~ % terraform -help plan
Usage: terraform [global options] plan [options]

  Generates a speculative execution plan, showing what actions Terraform
  would take to apply the current configuration. This command will not
  actually perform the planned actions.

  You can optionally save the plan to a file, which you can then pass to
  the "apply" command to perform exactly the actions described in the plan.

Plan Customization Options:

  The following options customize how Terraform will produce its plan. You
  can also use these options when you run "terraform apply" without passing
  it a saved plan, in order to plan and apply in a single command.

  -destroy            Select the "destroy" planning mode, which creates a plan
                      to destroy all objects currently managed by this
                      Terraform configuration instead of the usual behavior.

  -refresh-only       Select the "refresh only" planning mode, which checks
                      whether remote objects still match the outcome of the
                      most recent Terraform apply but does not propose any
                      actions to undo any changes made outside of Terraform.

  -refresh=false      Skip checking for external changes to remote objects
                      while creating the plan. This can potentially make
                      planning faster, but at the expense of possibly planning
                      against a stale record of the remote system state.

  -replace=resource   Force replacement of a particular resource instance using
                      its resource address. If the plan would've normally
                      produced an update or no-op action for this instance,
                      Terraform will plan to replace it instead.

  -target=resource    Limit the planning operation to only the given module,
                      resource, or resource instance and all of its
                      dependencies. You can use this option multiple times to
                      include more than one object. This is for exceptional
                      use only.

  -var 'foo=bar'      Set a value for one of the input variables in the root
                      module of the configuration. Use this option more than
                      once to set more than one variable.

  -var-file=filename  Load variable values from the given file, in addition
                      to the default files terraform.tfvars and *.auto.tfvars.
                      Use this option more than once to include more than one
                      variables file.

Other Options:

  -compact-warnings   If Terraform produces any warnings that are not
                      accompanied by errors, shows them in a more compact form
                      that includes only the summary messages.

  -detailed-exitcode  Return detailed exit codes when the command exits. This
                      will change the meaning of exit codes to:
                      0 - Succeeded, diff is empty (no changes)
                      1 - Errored
                      2 - Succeeded, there is a diff

  -input=true         Ask for input for variables if not directly set.

  -lock=false         Don't hold a state lock during the operation. This is
                      dangerous if others might concurrently run commands
                      against the same workspace.

  -lock-timeout=0s    Duration to retry a state lock.

  -no-color           If specified, output won't contain any color.

  -out=path           Write a plan file to the given path. This can be used as
                      input to the "apply" command.

  -parallelism=n      Limit the number of concurrent operations. Defaults to 10.

  -state=statefile    A legacy option used for the local backend only. See the
                      local backend's documentation for more information.


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