Basic

Question 1

Installation of Terraform

Answer 1

1. Download Terraform binaries
2. Set path
3. Run command: terraform -version

Question 2

Is Terraform a functional language?

Answer 2

No, it’s an declarative language

Question 3

What is “main.tf”? Where should we put this file?

Answer 3

This is main file from which Terraform starts it’s execution. It’s location should be “root” folder.

Question 4

What is the “general” syntax of any Terraform object?

Answer 4

… {}

Question 5

How to mention the provider in terraform?

Answer 5

It should be mentioned inside the “main.tf” file.
provider “aws” {
region = “ap-south-1”
}

Question 6

What is the “general” syntax of “resource” object?

Answer 6

resource { }

Question 7

How arguments are named inside any object?

Answer 7

It is named as “key-value” pair. The name should be all small and “snake-case”.
my_attrbute = “value”

Question 8

How to create instance via Terraform

Answer 8

resource "aws_instance" "myInstance" {
  ami = "asaas"
  instance_type = "t2.micro"
  vpc_security_group_ids = [ "id1", "id2"]
  user_data = "heredoc"
  tags = {
     name = "test"
  }
}

Question 9

What are different terraform files we should ignore from being pushing to source code?

Answer 9

.terraform
.tfstate
.tfstate.backup

Question 10

How to use “heredoc” inside the terraform?

Answer 10

user_data =

Question 11

How to create a security group resource in terraform?

Answer 11

resource "aws_security_group" "instance" {
   name = "mySecurityGroup"
   ingress = {
     from_port = 8080
     to_port = 8080
     protocol = "tcp"
     cidr_block = [ "0.0.0.0/0"]
 }
}

Question 12

What is interpolation syntax used in Terraform?

Answer 12

inside double quote and starting with $

“${}

Question 13

What is the general syntax of interpolation syntax in Terraform?

Answer 13

”${resourceType.resourceName.resourceAttribute}”

Question 14

What is the general syntax of variable object?

Answer 14

variable {
configs..[]
}

Question 15

What are the different config parameters which we can use inside the variable object?

Answer 15

1. description
2. type
3. default

Question 16

Are config arguments of variable object mandatory?

Answer 16

No, those are all optional.

Question 17

How Terraform searches for the value of “variable object”?

Answer 17

It searches in following order:

1. search is there any variable value passed in “apply” command with -var or -var-file option
2. If not found, it searches for the environment variable declared in format “TF_VAR_”
3. If not found, it fallback to the default value of the variable
4. If default value is not provided, it prompts the user during apply command

Question 18

What are different “types” supported by the “type” of the config argument of variable object?

Answer 18

string
list
map
set
boolean
tuple
bool
object
any

Question 19

Do we need to add double quote around string type?

Answer 19

No, we don’t need to put double quote around “type”

Question 20

How to access a variable in Terraform?

Answer 20

It is done by following interpolation syntax:

“${var.}

Question 21

What is output variable object? Why we need that?

Answer 21

Output variable is the “way” of printing output of any resource on console. It helps us to get the data.

Question 22

Write the syntax of output object?

Answer 22

output “public_ip” {
value = “${aws_resource.instance.public_ip}”
}

Question 23

When we gets the output value of output variable?

Answer 23

Right after “apply” command.

Question 24

Is it possible to get the output value without apply command?

Answer 24

yes, by using the output command:

terraform output

Question 25

Solve this scenario:
We ran the apply command and get the value of output variable. However, we forgot to store same somewhere safe. How can we retrieve it later on?

Answer 25

After apply command the “output” variables gets stored inside the “state” files. As long as we have state-file, we can retrieve it using following command:
»> terraform output

Question 26

What are main responsibilities of ASG?

Answer 26

1. Server provisioning

2. Health monitoring

Question 27

What is the Launch configuration and write down it’s syntax ?

Answer 27

Launch configuration is responsible for “launching” the EC2 machines. Its object is very similar to the “aws_instance” syntax:
resource “aws_launch_configuration” “myLC” {
image_id = “asfasf”
instance_type = “t2.micro”
security_groups = [“id1”, “id2”]
user_data =

Question 28

Can we provide “tags” in Launch configuration?

Answer 28

NO, the tags are provided by ASG to the machines.

Question 29

What is “meta” parameter in Terraform?

Answer 29

A meta parameter is something which is available in all resources.

Question 30

Explain “lifecycle” parameter object and its config?

Answer 30

lifecycle is a meta parameter, which controls the lifecycle of any resource. It’s object contains following config
“create_before_destory” = true/false

Question 31

What is done by “create_before_destroy” attribute of lifecycle parameter?

Answer 31

It ensures, new resource must be created before destruction of original resource.

Question 32

Is it mandatory to add “lifecycle” parameter in all dependent resources?

Answer 32

yes, it is mandatory, otherwise we will get “cyclic” dependency error.

Question 33

What is “data” source object and how to use same?

Answer 33

Data source object is required to fetch some data from the service provider. In order to use same, we need to create it’s object:
data “aws_availability_zones” “all” {}

Question 34

Is body of “data source” object always empty?

Answer 34

yes

Question 35

What’s the syntax of data source object?

Answer 35

data

Question 36

Does ASG requires “AZs” to create the instances?

Answer 36

Yes. It directs the “lC” to create EC2 min multiple AZs.

Question 37

Does Load balancer needs “AZs” to route the traffic?

Answer 37

yes, LB needs the AZ info to route the traffice

Question 38

What are the important config of a LB?

Answer 38

1. The availability zones, in which it will route the traffic
2. Security Groups for opening it’s required port
3. Listener object for port fowarding
4. Health checks of VMs

Question 39

Write the syntax of LB?

Answer 39

>>> resource “aws_elb” “elb” {
>>>  availability_zones = [”${data.aws_availability_zones.all.names”]
>>> security_groups = [”${aws_security_groups.elb.id}”]
>>> listener {
>>>  lb_port = 80
>>>  lb_protocol = “http”
>>>  instance_port = “${var.server_port}”
>>>  }
>>>  health_check {
>>>  target = “http:${var.server.port}/”
>>>  interval = 30
>>> timeout = 3
>>>. healthy_threshold = 2
>>>  unhealthy_threshold = 2
>>> }

Question 40

What are the main config of ASG

Answer 40

1. Launch configuration
2. LB
3. Availability zones
4. health check type

Question 41

Write syntax of ASG

Answer 41

resource "aws_autoscaling_group" "instanceASG" {
  max_size = 2
  min_size = 1
  launch_configuration = "${aws_launch_configuration.instance_launch_configuration.id}"
  availability_zones = "${data.aws_availability_zones.all.names}"
  health_check_type = "ELB"
  load_balancers = ["${aws_elb.elb.id}"]
  tag {
    key                 = "createdBy"
    propagate_at_launch = false
    value               = "Terraform"
  }
}