KodeKloud Notes

Welcome to this hands-on lab on OpenTofu commands. Here, you’ll learn how to visualize, validate, plan, and apply your infrastructure-as-code (IaC) configurations using the tofu CLI. By the end of this guide, you’ll be comfortable generating dependency graphs, troubleshooting HCL errors, and managing provider plugins.

1. Visualizing Resources

To inspect resource dependencies, generate a DOT graph:

tofu graph > graph.dot

You can then render graph.dot with Graphviz to visualize your IaC topology.

Subcommand	Purpose	Example
tofu graph	Generate DOT-format dependency graph	`tofu graph > graph.dot`
tofu validate	Validate HCL configuration	`tofu validate`
tofu plan	Create an execution plan	`tofu plan`
tofu apply	Apply the planned changes	`tofu apply`
tofu fmt	Format Terraform/OpenTofu files	`tofu fmt`
tofu state	Inspect or modify the state file	`tofu state show local_file.key_data`
tofu providers	Manage provider plugins	`tofu providers --help`

2. Validating Configuration

Before creating any resources, validate your HCL syntax and catch typos:

Change into your project directory:

cd /root/opentofu-projects/project-shazam

Run the validator:
```
tofu validate
```

The image shows a Visual Studio Code interface with a task description on the left about fixing configuration errors using the `tofu validate` command. On the right, there's a terminal and file explorer open, displaying a project directory structure.

If you see:

Error: An argument named "dsa_bits" is not expected here.
  on main.tf line 8, in resource "tls_private_key" "private_key":
   8:   dsa_bits = 2048

Did you mean "rsa_bits"?

Warning

Always match algorithm-specific arguments. In this case, replace dsa_bits with rsa_bits for an RSA key.

Correct the block in main.tf:

resource "tls_private_key" "private_key" {
  algorithm = "RSA"
  rsa_bits  = 2048
}

Re-run tofu validate until no errors remain.

3. Planning and Applying

3.1 Generating a Plan

Create an execution plan to preview changes:

tofu plan

You’ll see which resources will be added, changed, or destroyed.

3.2 First Apply Attempt

Apply the plan:

tofu apply

If you encounter:

Error: Provider produced inconsistent final plan
...
inconsistent values for sensitive attribute

it means the syntax was valid but some resource arguments are incompatible.

4. Fixing the TLS Resource Block

Ensure your main.tf includes only RSA-compatible settings and the local file resource:

resource "local_file" "key_data" {
  filename        = "/tmp/.pki/private_key.pem"
  content         = tls_private_key.private_key.pem
  file_permission = "0400"
}

resource "tls_private_key" "private_key" {
  algorithm = "RSA"
  rsa_bits  = 2048
}

resource "tls_cert_request" "csr" {
  private_key_pem = file("/tmp/.pki/private_key.pem")
  depends_on      = [local_file.key_data]

  subject {
    common_name  = "flexit.com"
    organization = "FlexIT Consulting Services"
  }
}

Re-initialize, plan, and apply:

tofu init
tofu plan
tofu apply

If tofu apply completes without errors, your configuration is now correct.

5. Formatting Code

Keep your files consistent:

tofu fmt

This enforces HCL canonical style across all .tf files.

6. Inspecting State

Query the state for a specific resource:

cd ~/opentofu-projects/project-shazam
tofu state show local_file.key_data

Check the filename attribute (e.g., /tmp/.pki/private_key.pem) to confirm it matches expectations.

7. Providers Subcommands

OpenTofu uses providers to interact with external APIs. To list available provider commands:

tofu providers --help

Common subcommands include:

mirror
list
install
remove

8. Reviewing Downloaded Providers

Without browsing the directory directly, list installed plugins:

tofu providers

The image shows a coding environment with a file explorer and a code editor displaying a JSON file related to Terraform configuration. There is also a terminal at the bottom with commands related to navigating directories and managing provider plugins.

You should see entries like:

registry.opentofu.org/hashicorp/aws
registry.opentofu.org/hashicorp/local

Links and References

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