Terraform with AWS

I'm training my writing in English, please, in case of mistakes, be patient and be happy :)

01 - Start

Links of reference to the documentation to HashiCorp - Terraform

To create a S3 Bucket https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/s3_bucket#

Step by step to create resource(s)

1. To init Terraform

$ terraform init

2. To view what will execute on plan

$ terraform plan

3. To apply the file manifest

$ terraform apply

02 - Change and Destroy

When I change simple data and execute

$ terraform plan

the output is

aws_s3_bucket.my-test-bucket: Refreshing state... [id=my-tf-test-bucket-devops-lab-9043943867348987878986743]

Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following
symbols:
  ~ update in-place

Terraform will perform the following actions:

  # aws_s3_bucket.my-test-bucket will be updated in-place
  ~ resource "aws_s3_bucket" "my-test-bucket" {
        id                          = "my-tf-test-bucket-devops-lab-9043943867348987878986743"
      ~ tags                        = {
          ~ "UpdateAt"    = "2023-01-20" -> "2023-01-21"
            # (4 unchanged elements hidden)
        }
      ~ tags_all                    = {
          ~ "UpdateAt"    = "2023-01-20" -> "2023-01-21"
            # (4 unchanged elements hidden)
        }
        # (9 unchanged attributes hidden)

        # (2 unchanged blocks hidden)
    }

Plan: 0 to add, 1 to change, 0 to destroy.

───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────

Note: You didn't use the -out option to save this plan, so Terraform can't guarantee to take exactly these actions if you run
"terraform apply" now.

---

If you change the resource name for example, and run the command terraform plan observe that the output on the end message is any like as

Plan: 1 to add, 0 to change, 1 to destroy.

To the resource be destroy and a new be created

$ terraform plan -out="tfplan.out"

to execute changes, run

$ terraform apply "tfplan.out"

the output will be any like that

aws_s3_bucket.my-test-bucket: Destroying... [id=my-tf-test-bucket-devops-lab-90439478986743change]
aws_s3_bucket.my-test-bucket: Destruction complete after 1s
aws_s3_bucket.my-test-bucket: Creating...
aws_s3_bucket.my-test-bucket: Creation complete after 4s [id=my-tf-test-bucket-devops-lab-90439478986743change1]

Apply complete! Resources: 1 added, 0 changed, 1 destroyed.

🤪 Congrats

03 - Working with variables

Here, we did work with variables. If you don't have the parameter default when executing the command the prompt show to input data.

This, propose flexibility in the hour to provide your infra.

Other option to work without default parameter is especifing on command line, for example

$ TF_VAR_aws_profile=eric-useast1 terraform plan

or

Using a flag

$ terraform plan -var="aws_profile=eric-useast1" -var="instance_type=t3.large"

In the example above, the prompt won't be shown.

Now, we work with a file with variables and, tfor work hin, just run using the flag like

$ terraform plan -var-file="prod.tfvars"

04 - Working with interpolation, locals and outputs

• Interpolation, see in the practice browsing on folder in file s3.tf

code bucket = "${random_pet.bucket.id}-${var.environment}"

• When we use one or more values repeatedly, we can create a file called locals.tf

• Using outputs to expose information, we study more deeply in the future

terraform plan -out="tfplan.out"
random_pet.bucket: Refreshing state... [id=evenly-secondly-solely-dear-kiwi]
aws_s3_bucket.this: Refreshing state... [id=evenly-secondly-solely-dear-kiwi-dev]
aws_s3_object.this: Refreshing state... [id=config/ips.json]

Changes to Outputs:
  + bucket_domain_name = "evenly-secondly-solely-dear-kiwi-dev.s3.amazonaws.com"
  + bucket_name        = "evenly-secondly-solely-dear-kiwi-dev"
  + buckt_arn          = "arn:aws:s3:::evenly-secondly-solely-dear-kiwi-dev"
  + name               = "evenly-secondly-solely-dear-kiwi-dev/config/ips.json"

You can apply this plan to save these new output values to the Terraform state, without changing any real infrastructure.

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Links of reference

Interpolation https://developer.hashicorp.com/terraform/language/expressions/strings#interpolation

Provider Random resource random_pet https://registry.terraform.io/providers/hashicorp/random/latest/docs/resources/pet

Outputs https://developer.hashicorp.com/terraform/language/values/outputs

05 - Modules

In this module, we create a public bucket to host a static website

http://rarely-terribly-vaguely-boss-cockatoo.s3-website-us-east-1.amazonaws.com/

Link of reference

https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/s3_bucket

https://github.com/hashicorp/terraform-template-dir/blob/master/variables.tf