Terraform Associate Cert Study

How do you install terraform on different OS?

// Mac OS brew install terraform // Windows choco install terraform https://learn.hashicorp.com/terraform/getting-started/install

How many ways you can configure provider versions?

1. With required_providers blocks under terraform block terraform { required_providers { aws = "~> 1.0" } } 2. Provider version constraints can also be specified using a version argument within a provider block. provider { version= "1.0" }

What is a remote-exec provisioner and when do we use it?

Another useful provisioner is remote-exec which invokes a script on a remote resource after it is created. This can be used to run a configuration management tool, bootstrap into a cluster, etc.

What does this symbol version = "~> 1.0" mean when defining versions?

Any version more than 1.0 and less than 2.0

How do you select alternate providers?

By default, resources use a default provider configuration inferred from the first word of the resource type name. For example, a resource of type aws_instance uses the default (un-aliased) aws provider configuration unless otherwise stated. resource "aws_instance" "foo" { provider = aws.west # ... }

What is the use of terraform being cloud-agnostic?

It simplifies management and orchestration, helping operators build large-scale multi-cloud infrastructures.

By default, provisioners that fail will also cause the Terraform apply itself to fail. How do you change this?

The on_failure setting can be used to change this. The allowed values are: continue: Ignore the error and continue with creation or destruction. fail: Raise an error and stop applying (the default behavior). If this is a creation provisioner, taint the resource. // Example resource "aws_instance" "web" { # ... provisioner "local-exec" { command = "echo The server's IP address is ${self.private_ip}" on_failure = "continue" } }

How do you apply constraints for the provider versions?

The required_providers setting is a map specifying a version constraint for each provider required by your configuration. terraform { required_providers { aws = ">= 2.7.0" } }

What are the types of provisioners?

local-exec remote-exec

How do you configure a Provider?

provider "google" { project = "acme-app" region = "us-central1" } The name given in the block header ("google" in this example) is the name of the provider to configure. Terraform associates each resource type with a provider by taking the first word of the resource type name (separated by underscores), and so the "google" provider is assumed to be the provider for the resource type name google_compute_instance. The body of the block (between { and }) contains configuration arguments for the provider itself. Most arguments in this section are specified by the provider itself; in this example both project and region are specific to the google provider.

What is the command to initialize the directory?

terraform init

How do you upgrade to the latest acceptable version of the provider?

terraform init --upgrade It upgrades to the latest acceptable version of each provider. This command also upgrades to the latest versions of all Terraform modules.

What is the command to show the execution plan and not apply?

terraform plan

How do you inspect the current state of the infrastructure applied?

terraform show When you applied your configuration, Terraform wrote data into a file called terraform.tfstate. This file now contains the IDs and properties of the resources Terraform created so that it can manage or destroy those resources going forward.

If your state file is too big and you want to list the resources from your state. What is the command?

terraform state list https://learn.hashicorp.com/terraform/getting-started/build#manually-managing-state

How do you manually taint a resource?

terraform taint resource.id

Does the taint command modify the infrastructure?

terraform taint resource.id This command will not modify infrastructure, but does modify the state file in order to mark a resource as tainted. Once a resource is marked as tainted, the next plan will show that the resource will be destroyed and recreated and the next apply will implement this change.

If different teams are working on the same configuration. How do you make files to have syntactically valid and internally consistent?

terraform validate This command will check and report errors within modules, attribute names, and value types. Validate your configuration. If your configuration is valid, Terraform will return a success message.

What is the naming scheme for provider plugins?

terraform-provider-<NAME>_vX.Y.Z

What is the name of the terraform state file?

terraform.tfstate

Third-party plugins should be manually installed. Is that true?

True

72. Expressions in provisioner blocks cannot refer to their parent resource by name. Is this true?

True The self object represents the provisioner's parent resource, and has all of that resource's attributes. For example, use self.public_ip to reference an aws_instance's public_ip attribute.

The command terraform init cannot install third-party plugins? True or false?

True. Install third-party providers by placing their plugin executables in the user plugins directory. The user plugins directory is in one of the following locations, depending on the host operating system. Once a plugin is installed, terraform init can initialize it normally. You must run this command from the directory where the configuration files are located.

What are the Providers?

A provider is a plugin that Terraform uses to translate the API interactions with the service. A provider is responsible for understanding API interactions and exposing resources. Because Terraform can interact with any API, you can represent almost any infrastructure type as a resource in Terraform. https://www.terraform.io/docs/configuration/providers.html

What is Provider Plugin Cache?

By default, terraform init downloads plugins into a subdirectory of the working directory so that each working directory is self-contained. As a consequence, if you have multiple configurations that use the same provider then a separate copy of its plugin will be downloaded for each configuration. Given that provider plugins can be quite large (on the order of hundreds of megabytes), this default behavior can be inconvenient for those with slow or metered Internet connections. Therefore Terraform optionally allows the use of a local directory as a shared plugin cache, which then allows each distinct plugin binary to be downloaded only once.

How multi-cloud deployment is useful?

By using only a single region or cloud provider, fault tolerance is limited by the availability of that provider. Having a multi-cloud deployment allows for more graceful recovery of the loss of a region or entire provider.

What are Provisioners?

If you need to do some initial setup on your instances, then provisioners let you upload files, run shell scripts, or install and trigger other software like configuration management tools, etc.

Where do you describe all the components or your entire datacenter so that Terraform provision those?

Configuration files ends with *.tf

What is plug-in based architecture?

Defining additional features as plugins to your core platform or core application. This provides extensibility, flexibility and isolation

What is Provider initialization and why do we need?

Each time a new provider is added to configuration -- either explicitly via a provider block or by adding a resource from that provider -- Terraform must initialize the provider before it can be used. Initialization downloads and installs the provider's plugin so that it can later be executed.

What is the Terraform State?

Every time you run Terraform, it records information about what infrastructure it created in a Terraform state file. By default, when you run Terraform in the folder /some/folder, Terraform creates the file /some/folder/terraform.tfstate. This file contains a custom JSON format that records a mapping from the Terraform resources in your configuration files to the representation of those resources in the real world.

What are the use cases of Terraform?

Heroku App Setup Multi-Tier Applications Self-Service Clusters Software Demos Disposable Environments Software Defined Networking Resource Schedulers Multi-Cloud Deployment https://www.terraform.io/intro/use-cases.html

What are Day 0 and Day 1 activities?

IaC can be applied throughout the lifecycle, both on the initial build, as well as throughout the life of the infrastructure. Commonly, these are referred to as Day 0 and Day 1 activities. "Day 0" code provisions and configures your initial infrastructure. "Day 1" refers to OS and application configurations you apply after you've initially built your infrastructure.

How using IaC make it easy to provision infrastructure?

IaC makes it easy to provision and apply infrastructure configurations, saving time. It standardizes workflows across different infrastructure providers (e.g., VMware, AWS, Azure, GCP, etc.) by using a common syntax across all of them.

When terraform mark the resources are tainted?

If a resource successfully creates but fails during provisioning, Terraform will error and mark the resource as "tainted". A resource that is tainted has been physically created, but can't be considered safe to use since provisioning failed.

What do we need to use a remote-exec?

In order to use a remote-exec provisioner, you must choose an ssh or winrm connection in the form of a connection block within the provisioner. Here is an example provider "aws" { profile = "default" region = "us-west-2" } resource "aws_key_pair" "example" { key_name = "examplekey" public_key = file("~/.ssh/terraform.pub") } resource "aws_instance" "example" { key_name = aws_key_pair.example.key_name ami = "ami-04590e7389a6e577c" instance_type = "t2.micro" connection { type = "ssh" user = "ec2-user" private_key = file("~/.ssh/terraform") host = self.public_ip } provisioner "remote-exec" { inline = [ "sudo amazon-linux-extras enable nginx1.12", "sudo yum -y install Nginx", "sudo systemctl start Nginx" ] } }

How do you try experimental features?

In releases where experimental features are available, you can enable them on a per-module basis by setting the experiments argument inside a terraform block: terraform { experiments = [example] }

What is the purpose of the Terraform State?

Mapping to the Real World Terraform requires some sort of database to map Terraform config to the real world because you can't find the same functionality in every cloud provider. You need to have some kind of mechanism to be cloud-agnostic Metadata Terraform must also track metadata such as resource dependencies, pointer to the provider configuration that was most recently used with the resource in situations where multiple aliased providers are present. Performance When running a terraform plan, Terraform must know the current state of resources in order to effectively determine the changes that it needs to make to reach your desired configuration. For larger infrastructures, querying every resource is too slow. Many cloud providers do not provide APIs to query multiple resources at once, and the round trip time for each resource is hundreds of milliseconds. So, Terraform stores a cache of the attribute values for all resources in the state. This is the most optional feature of Terraform state and is done only as a performance improvement. Syncing When two people works on the same file and doing some changes to the infrastructure. Its very important for everyone to be working with the same state so that operations will be applied to the same remote objects. https://www.terraform.io/docs/state/purpose.html

Where is the location of the CLI configuration File?

On Windows, the file must be named named terraform.rc and placed in the relevant user's %APPDATA% directory. On all other systems, the file must be named .terraformrc (note the leading period) and placed directly in the home directory of the relevant user. The location of the Terraform CLI configuration file can also be specified using the TF_CLI_CONFIG_FILE environment variable.

When does the terraform does not recommend using provisions?

Passing data into virtual machines and other compute resources https://www.terraform.io/docs/provisioners/#passing-data-into-virtual-machines-and-other-compute-resources Running configuration management software https://www.terraform.io/docs/provisioners/#running-configuration-management-software

What are the advantages of Terraform?

Platform Agnostic State Management Operator Confidence https://learn.hashicorp.com/terraform/getting-started/intro

How do you initialize any Provider?

Provider initialization is one of the actions of terraform init. Running this command will download and initialize any providers that are not already initialized.

When you run "terraform init" command, all the providers are installed in the current working directory. Is this true?

Providers downloaded by "terraform init" are only installed for the current working directory; other working directories can have their own installed provider versions. Note that "terraform init" cannot automatically download providers that are not distributed by HashiCorp. See Third-party Plugins below for installation instructions.

Are provisioners runs only when the resource is created or destroyed?

Provisioners are only run when a resource is created or destroyed. Provisioners that are run while destroying are Destroy provisioners. They are not a replacement for configuration management and changing the software of an already-running server, and are instead just meant as a way to bootstrap a server.

What is multi-cloud deployment?

Provisioning your infrastructure into multiple cloud providers to increase fault-tolerance of your applications.

Why do we need Multiple Provider instances?

Some of the example scenarios: a. multiple regions for a cloud platform b. targeting multiple Docker hosts c. multiple Consul hosts, etc.

Terraform also does not automatically roll back and destroy the resource during the apply when the failure happens. Why?

Terraform also does not automatically roll back and destroy the resource during the apply when the failure happens, because that would go against the execution plan: the execution plan would've said a resource will be created, but does not say it will ever be deleted. If you create an execution plan with a tainted resource, however, the plan will clearly state that the resource will be destroyed because it is tainted. https://learn.hashicorp.com/terraform/getting-started/provision

How can Terraform build infrastructure so efficiently?

Terraform builds a graph of all your resources, and parallelizes the creation and modification of any non-dependent resources. Because of this, Terraform builds infrastructure as efficiently as possible, and operators get insight into dependencies in their infrastructure.

What is the CLI configuration File?

The CLI configuration file configures per-user settings for CLI behaviors, which apply across all Terraform working directories. It is named either .terraformrc or terraform.rc

What is Ideompodent in terms of IaC?

The idempotent characteristic provided by IaC tools ensures that, even if the same code is applied multiple times, the result remains the same.

What is a local-exec provisioner and when do we use it?

The local-exec provisioner executing a command locally on your machine running Terraform. We use this when we need to do something on our local machine without needing any external URL

How do you configure the required version of Terraform CLI can be used with your configuration?

The required_version setting can be used to constrain which versions of the Terraform CLI can be used with your configuration. If the running version of Terraform doesn't match the constraints specified, Terraform will produce an error and exit without taking any further actions.

Where do you put terraform configurations so that you can configure some behaviors of Terraform itself?

The special terraform configuration block type is used to configure some behaviors of Terraform itself, such as requiring a minimum Terraform version to apply your configuration. terraform { # ... }

How do you constrain the provider version?

To constrain the provider version as suggested, add a required_providers block inside a terraform block: terraform { required_providers { aws = "~> 1.0" } }

How do you enable Provider Plugin Cache?

To enable the plugin cache, use the plugin_cache_dir setting in the CLI configuration file. plugin_cache_dir = "$HOME/.terraform.d/plugin-cache" Alternatively, the TF_PLUGIN_CACHE_DIR environment variable can be used to enable caching or to override an existing cache directory within a particular shell session:

How do we define multiple Provider configurations?

To include multiple configurations for a given provider, include multiple provider blocks with the same provider name, but set the alias meta-argument to an alias name to use for each additional configuration. # The default provider configuration provider "aws" { region = "us-east-1" } # Additional provider configuration for west coast region provider "aws" { alias = "west" region = "us-west-2" }

By default, provisioners that fail will also cause the Terraform apply itself to fail. Is this true?

True

Terraform assumes an empty default configuration for any provider that is not explicitly configured. A provider block can be empty. Is this true?

True

Terraform supports both cloud and on-premises infrastructure platforms. Is this true?

True

When you are using plugin cache you end up growing cache directory with different versions. Whose responsibility to clean it?

User Terraform will never itself delete a plugin from the plugin cache once it's been placed there. Over time, as plugins are upgraded, the cache directory may grow to contain several unused versions which must be manually deleted.

Why do we need to initialize the directory?

When you create a new configuration — or check out an existing configuration from version control — you need to initialize the directory // Example provider "aws" { profile = "default" region = "us-east-1" } resource "aws_instance" "example" { ami = "ami-2757f631" instance_type = "t2.micro" } Initializing a configuration directory downloads and installs providers used in the configuration, which in this case is the aws provider. Subsequent commands will use local settings and data during initialization.

You applied the infrastructure with terraform apply and you have some tainted resources. You run an execution plan now what happens to those tainted resources?

When you generate your next execution plan, Terraform will not attempt to restart provisioning on the same resource because it isn't guaranteed to be safe. Instead, Terraform will remove any tainted resources and create new resources, attempting to provision them again after creation. https://learn.hashicorp.com/terraform/getting-started/provision

What is the location of the user plugins directory?

Windows: %APPDATA%\terraform.d\plugins All other systems: ~/.terraform.d/plugins

Only constants are allowed inside the terraform block. Is this correct?

Yes Within a terraform block, only constant values can be used; arguments may not refer to named objects such as resources, input variables, etc, and may not use any of the Terraform language built-in functions.

How do you define destroy provisioner and give an example?

You can define destroy provisioner with the parameter when provisioner "remote-exec" { when = "destroy" # <...snip...> }

What is Infrastructure as Code?

You write and execute the code to define, deploy, update, and destroy your infrastructure

What are the benefits of IaC?

a. Automation We can bring up the servers with one script and scale up and down based on our load with the same script. b. Reusability of the code We can reuse the same code c. Versioning We can check it into version control and we get versioning. Now we can see an incremental history of who changed what, how is our infrastructure actually defined at any given point of time, and we have this transparency of documentation. IaC makes changes idempotent, consistent, repeatable, and predictable.

How do you configure Multiple Provider Instances?

alias You can optionally define multiple configurations for the same provider, and select which one to use on a per-resource or per-module basis.

What is cloud-agnostic in terms of provisioning tools?

cloud-agnostic and allows a single configuration to be used to manage multiple providers, and to even handle cross-cloud dependencies.

How do you define provisioners?

resource "aws_instance" "example" { ami = "ami-b374d5a5" instance_type = "t2.micro" provisioner "local-exec" { command = "echo hello > hello.txt" } } Provisioner block within the resource block. Multiple provisioner blocks can be added to define multiple provisioning steps. Terraform supports multiple provisioners. https://learn.hashicorp.com/terraform/getting-started/provision

How do you manually install terraform?

step 1: Download the zip fille step 2: mv ~/Downloads/terraform /usr/local/bin/terraform

What is the command to create infrastructure?

terraform apply

If different teams are working on the same configuration. How do you make files to have consistent formatting?

terraform fmt This command automatically updates configurations in the current directory for easy readability and consistency.

What are the meta-arguments that are defined by Terraform itself and available for all provider blocks?

version: Constraining the allowed provider versions alias: using the same provider with different configurations for different resources

Is Terraform cloud-agostic?

yes

What should you use to set both a lower and upper bound on versions for each provider?

~> terraform { required_providers { aws = "~> 2.7.0" } }