Terraform apply for execution - Step-by-Step Execution

Process Flow - Terraform apply for execution

Write Terraform config

↓

terraform init

↓

terraform plan

↓

terraform apply

↓

Resources created/updated

↓

terraform state updated

↓

Infrastructure ready

This flow shows how Terraform applies configuration to create or update cloud resources, updating the state to reflect changes.

Execution Sample

Terraform

resource "aws_s3_bucket" "example" {
  bucket = "my-unique-bucket-12345"
  acl    = "private"
}

terraform apply

This code creates a private AWS S3 bucket named 'my-unique-bucket-12345' when 'terraform apply' is run.

Process Table

Step	Action	Evaluation	Result
1	Read Terraform config	Parse resource block	Resource aws_s3_bucket.example identified
2	terraform init	Initialize backend and providers	Providers downloaded, backend configured
3	terraform plan	Compare desired state with current state	Plan shows 1 resource to add
4	terraform apply - confirm	User confirms apply	Apply starts
5	Create aws_s3_bucket.example	Send API request to AWS	Bucket created successfully
6	Update terraform state	Record new resource in state file	State updated with aws_s3_bucket.example
7	Apply complete	No errors	Infrastructure matches config

💡 All resources created successfully, terraform state updated, apply finished

Status Tracker

Variable	Start	After Step 3	After Step 6	Final
terraform_state	empty	shows planned resource	includes aws_s3_bucket.example	final with created resource
resource_status	not created	planned to create	created	created

Key Moments - 3 Insights

Why does terraform plan show changes before apply?

terraform plan compares current state with config and shows what will change; see execution_table step 3.

What happens if user does not confirm apply?

Apply stops before making changes; no resources created; see execution_table step 4.

How does terraform know what resources exist after apply?

It updates the state file after successful creation; see execution_table step 6.

Visual Quiz - 3 Questions

Look at the execution table, at which step is the AWS bucket actually created?

A Step 3

B Step 5

C Step 6

D Step 7

💡 Hint

Check the 'Action' and 'Result' columns in execution_table row 5.

According to variable_tracker, what is the state of 'resource_status' after step 3?

A planned to create

B not created

C created

D deleted

💡 Hint

Look at 'resource_status' value under 'After Step 3' in variable_tracker.

If the user declines confirmation at step 4, what happens to the terraform state?

A State is updated with new resource

B State is deleted

C State remains unchanged

D State is partially updated

💡 Hint

Refer to key_moments about user confirmation and execution_table step 4.

Concept Snapshot

Terraform apply runs after init and plan.
It creates or updates resources to match config.
User confirmation is required before changes.
State file updates after successful apply.
Apply stops if user declines confirmation.

Full Transcript

Terraform apply is the command that makes your cloud resources match your configuration. First, you write your config file describing resources like an AWS S3 bucket. Then you run 'terraform init' to prepare providers. Next, 'terraform plan' shows what changes will happen. When you run 'terraform apply', Terraform asks for confirmation. After you confirm, it creates or updates resources by calling cloud APIs. Once done, it updates the state file to remember what exists. If you do not confirm, no changes happen. This process ensures your cloud matches your desired setup safely and clearly.

Practice

1. What does the terraform apply command do in simple terms?

easy

A. It backs up your cloud resources to local storage.

B. It creates or changes cloud resources based on your configuration.

C. It only shows a list of resources without making changes.

D. It deletes all your cloud resources immediately.

Solution

1. Step 1: Understand the purpose of terraform apply

   The command is used to make your cloud setup real by creating or updating resources defined in your configuration files.

2. Step 2: Compare options with command behavior

   Only It creates or changes cloud resources based on your configuration. correctly describes this behavior. Options A, B, and C describe actions terraform apply does not perform.

3. Final Answer:

   It creates or changes cloud resources based on your configuration. -> Option B

4. Quick Check:

   terraform apply = create/change resources [OK]

Hint: Remember: apply means 'make changes happen' [OK]

Common Mistakes:

• Thinking terraform apply only shows plans without applying
• Confusing terraform apply with terraform destroy
• Assuming terraform apply backs up resources

2. Which of the following is the correct syntax to run terraform apply without asking for approval?

easy

A. terraform apply -skip-confirm

B. terraform apply --no-approval

C. terraform apply -auto-approve

D. terraform apply --force

Solution

1. Step 1: Recall terraform apply options for skipping approval

   The official option to skip manual approval is -auto-approve.

2. Step 2: Verify other options

   Options B, C, and D are not valid terraform flags and will cause errors.

3. Final Answer:

   terraform apply -auto-approve -> Option C

4. Quick Check:

   -auto-approve skips approval [OK]

Hint: Use -auto-approve to skip approval prompt [OK]

Common Mistakes:

• Using incorrect flags like --no-approval
• Trying to use --force which is invalid
• Assuming terraform apply never asks for approval

3. Given this terraform apply output snippet:

Plan: 2 to add, 1 to change, 0 to destroy.

What will happen after you approve the apply?

medium

A. Two resources will be created, one resource will be updated, none deleted.

B. Two resources will be deleted, one created, none updated.

C. One resource will be created, two updated, none deleted.

D. No changes will happen because destroy count is zero.

Solution

1. Step 1: Interpret the plan summary

   The plan says 2 to add means 2 new resources will be created, 1 to change means 1 existing resource will be updated, and 0 to destroy means no resources will be deleted.

2. Step 2: Match the plan to the options

   Only Two resources will be created, one resource will be updated, none deleted. correctly describes this outcome. Options A, C, and D misunderstand the counts.

3. Final Answer:

   Two resources will be created, one resource will be updated, none deleted. -> Option A

4. Quick Check:

   Plan add=2, change=1, destroy=0 [OK]

Hint: Add = create, change = update, destroy = delete [OK]

Common Mistakes:

• Mixing up add and destroy counts
• Assuming zero destroy means no changes at all
• Confusing change with destroy

4. You run terraform apply but get an error: Error: No configuration files found. What is the likely cause?

medium

A. You ran terraform apply in a directory without terraform files.

B. You forgot to initialize terraform with terraform init.

C. You used the wrong terraform version.

D. You did not approve the plan before applying.

Solution

1. Step 1: Understand the error message

   The error says no configuration files found, meaning terraform cannot find any .tf files in the current folder.

2. Step 2: Evaluate options

   You ran terraform apply in a directory without terraform files. matches this cause. You forgot to initialize terraform with terraform init. would cause a different error about initialization. You used the wrong terraform version. is unlikely to cause this specific error. You did not approve the plan before applying. is unrelated because approval happens after plan generation.

3. Final Answer:

   You ran terraform apply in a directory without terraform files. -> Option A

4. Quick Check:

   No .tf files = error [OK]

Hint: Check current folder for .tf files before apply [OK]

Common Mistakes:

• Assuming terraform init missing causes this error
• Thinking approval is needed before apply runs
• Blaming terraform version without checking files

5. You want to automate terraform apply in a CI/CD pipeline but avoid manual approval. Which command and practice is best?

hard

A. Use terraform apply --force to skip all checks.

B. Run terraform apply directly without plan or approval.

C. Run terraform plan only, then manually approve changes later.

D. Use terraform apply -auto-approve after running terraform plan and saving the plan file.

Solution

1. Step 1: Understand CI/CD automation needs

   Automation requires no manual approval and safe application of changes. Saving a plan file ensures the exact changes are applied.

2. Step 2: Evaluate command options

   Use terraform apply -auto-approve after running terraform plan and saving the plan file. correctly uses terraform plan to create a plan file, then applies it with -auto-approve to skip manual confirmation. Run terraform apply directly without plan or approval. skips planning, which is risky. Run terraform plan only, then manually approve changes later. requires manual approval, not automated. Use terraform apply --force to skip all checks. uses an invalid flag.

3. Final Answer:

   Use terraform apply -auto-approve after running terraform plan and saving the plan file. -> Option D

4. Quick Check:

   Plan then apply with -auto-approve for automation [OK]

Hint: Plan first, then apply with -auto-approve in automation [OK]

Common Mistakes:

• Skipping plan step in automation
• Using invalid flags like --force
• Expecting manual approval in CI/CD