Terraform Basics Flashcards
Providers, Resources, State File, Keys, Variable Types, User Input, Dependencies, Built-In Functions, Versioning, Modules (70 cards)
Write a basic **provider block **for AWS for region “eu-west-2”
provider "aws" {
region = "eu-west-2"
}What are “1” and “2” in the resource block? Provide examples for creating an EC2 instance.
resource "1" "2" {
...
}
1: Resource Type
ex: “aws_instance”
2: Resource Name
ex: “my_instance”
terraform init creates a ____ file called ____
State file
terraform.tfstate
What happens if you:
1. terraform apply
2. Delete the terraform.tfstate file
3. terraform apply again
Why does this happen?
The resources are created a second time.
This is because there is no state file to tell Terraform which resources already exist.
One way to avoid hard-coding variables into Terraform is by using ____ variables that are set in the Windows CLI with the ____ command or in Linux with the ____ command
Env variables
Linux: export
Windows CLI: setx
Another way to avoid hard-coding variables into Terraform, specifically for AWS, is to use ____, which stores credentials in a ____ folder.
AWS CLI
Stores variables in a hidden folder
Declare a** string** variable called “vpcname” with a default value “myvpc”
variable "vpcname" {
type = "string"
default = "myvpc"
}Declare a number variable called “sshport” with a default value 22
variable "sshport" {
type = "number"
default = 22
}Declare a boolean variable called “enableDebug” that defaults to false
variable "enableDebug" {
type = bool
default = false
}What behavior does a list variable mimic from other languages?
Declare a list of strings variable called “mylist” with default entries of “First” and “Second”
List is like an array.
variable "mylist" {
type = list(string)
default = ["First", "Second"]
}
What is a map variable?
Declare a map variable called “mymap” with default values of your choice.
A map is a set of one or more key-value pairs.
variable "mymap" {
type = "map"
default = {
Key1 = "Value1"
Key2 = "Value 2"
}
}
- Declare a string variable called “vpcname” with default value “myvpc”
- Declare a list variable called “mylist” with default values “First” and “Second”
- Declare an aws_vpc resource called “myvpc” with CIDR block “10.0.0.0/16”, a tag called “Name” equal to the value of the vpcname variable, and a tag called “Item” equal to the value of the first item in “mylist”.
variable "vpcname" {
type = "string"
default = "myvpc"
}
variable "mylist" {
type = "list"
default = ["First", "Second"]
}
aws_vpc "myvpc" {
cidr_block = "10.0.0.0/16"
tags = {
Name = var.vpcname
Item = var.mylist[0]
}
}What is string interpolation? How do you do it in terraform?
Replace the value inside of a string with a variable.
“My name is ${var.name}”
variable "mymap" {
type = map
default = {
Key1 = "Value1"
Key2 = "Value2"
}
}
How do you reference the value of Key1 from this variable?
var.mymap[“Key1”]
What denotes a variable as being set by user input?
What are the rules for when Terraform prompts for this input?
A variable that lacks a default value.
Always prompted with plan
Only prompted with apply if there is no saved value from plan
Declare a string variable called “instance_name” that prompts the user “Set the name of the Instance”.
variable "instance_name" {
type = string
description = "Set the name of the Instance"
}How would you reference the “id” attribute of a resource that is created?
Give an example for an EC2 instance called “myinstance”
Hint: ____.____.id
resource type.resource name.id
ex: aws_instance.myinstance.id
Given that your Terraform is creating an EC2 instance called “mySQL_instance”, create an output to display it’s ID.
output "instanceid" {
value = aws_instance.mySQL_instance.id
}What is the only step in which outputs are available? Why?
apply because the resource must actually be created.
Fill in the block to assign tags from a map variable called “my-tags” to the instance:
aws_instance "my-instance" {
ami = "ami-053b0d53c279acc90"
instance_type = "t2.micro"
tags = \_\_\_\_
}
tags = var.my-tags
Variable types:
A ____ is an ordered collection that allows duplicates. Uses ____ characters to contain items.
A ____ is an unordered collection with unique values. Uses ____ characters to contain items.
A ____ is an unordered collection of key-value pairs with unique keys. Uses ____ characters to contain items.
A ____ is a fixed-length, ordered collection that allows multiple data types. Uses ____ characters to contain items.
Which types can be used with for_each to create multiple EC2 instances? Why?
A list is ordered and allows duplicates. Uses brackets.["First", "Second", "Second", "Third"]
A set is unordered and must be unique values. Uses brackets.["John", "Joe", "Jim"]
A map is unordered key-value pairs and must be unique keys. Uses curly brackets.
{
Key1 = Value1
Key2 = Value2
}
A tuple is ordered, fixed-length, and allows multiple data types. Uses brackets. Used to contain multiple values in a strict structure. ["web-server", 8080, true]
Can use for_each with sets or maps to create multiple EC2 instances because they enforce unique values.
Fill in the block to create a separate EC2 instance for each item in the set.
variable instance_names {
type = set(string)
default = ["First", "Second", "Third"]
}
resource "aws_instance" "example" {
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
ami = "ami-053b0d53c279acc90"
tags = {
Name = \_\_\_\_\_\_
}
}
variable instance_names {
type = set(string)
default = ["First", "Second", "Third"]
}
resource "aws_instance" "example" {
for_each = var.instance_names
ami = "ami-053b0d53c279acc90"
tags = {
Name = each.value
}
}When using for_each to loop through a list, Terraform provides ____ for accessing the values.
When using for_each to loop through a map, Terraform provides ____ for accessing the values.
**List: ** each.value
**Map: ** each.key, each.value
What is a dynamic block? What 2 variable types is it usually paired with? What 2 components are usually in the dynamic block?
A way to generate multiple blocks dynamically from a list or map variable.
Paired with list or map variable.
Usually there’s also a for_each and a content block.
