Zero-downtime deployment pattern in Terraform - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a new AWS EC2 instance resource.

Terraform

resource "aws_instance" "app_server" {
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = "[1]"
}

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Ac5.xlarge

Bt2.micro

Cm5.large

Dt3.micro

Attempts:

3 left

💡 Hint

Common Mistakes

Using an instance type that is too large for simple applications.

Using an instance type that is deprecated or unavailable in the region.

The 't3.micro' instance type is a common choice for lightweight applications and supports burstable CPU performance.

2fill in blank

medium

Complete the code to create an AWS Elastic Load Balancer (ELB) resource.

Terraform

resource "aws_elb" "app_elb" {
  name               = "app-elb"
  availability_zones = ["us-west-2a", "us-west-2b"]
  listener {
    instance_port     = 80
    instance_protocol = "HTTP"
    lb_port           = [1]
    lb_protocol       = "HTTP"
  }
}

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A443

B8080

C80

D22

Attempts:

3 left

💡 Hint

Common Mistakes

Using port 443 without configuring HTTPS.

Using a non-standard port that clients won't connect to.

The load balancer port should be 80 to accept HTTP traffic on the standard web port.

3fill in blank

hard

Fix the error in the code to properly attach instances to the ELB.

Terraform

resource "aws_elb_attachment" "app_attachment" {
  elb      = aws_elb.app_elb.name
  instance = [1]
}

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Aaws_instance.app_server.public_dns

Baws_instance.app_server.id

Caws_instance.app_server.private_ip

Daws_instance.app_server.name

Attempts:

3 left

💡 Hint

Common Mistakes

Using the instance name or IP instead of the ID.

Using an attribute that does not uniquely identify the instance.

The ELB attachment requires the instance ID, which uniquely identifies the EC2 instance.

4fill in blank

hard

Fill both blanks to create a lifecycle rule that prevents Terraform from destroying the old instance immediately.

Terraform

resource "aws_instance" "old_app_server" {
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = "t3.micro"

  lifecycle {
    [1] = true
    [2]  = true
  }
}

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Acreate_before_destroy

Bprevent_destroy

Cignore_changes

Dreplace_triggered_by

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing 'ignore_changes' with lifecycle control.

Not using 'create_before_destroy' causing downtime.

The 'create_before_destroy' ensures the new instance is created before the old one is destroyed, and 'prevent_destroy' protects the resource from accidental deletion.

5fill in blank

hard

Fill all three blanks to define a Terraform output that shows the ELB DNS name after deployment.

Terraform

output "elb_dns_name" {
  value = [1].[2].[3]
}

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Aaws_elb

Bapp_elb

Cdns_name

Dname

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'name' instead of 'dns_name' for the ELB attribute.

Mixing resource names or types incorrectly.

The output references the ELB resource 'aws_elb.app_elb' and accesses its 'dns_name' attribute to show the load balancer's DNS.