Launching an EC2 instance in AWS - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ service_behavior

intermediate

What happens when you launch an EC2 instance without specifying a security group?

You launch an EC2 instance but do not specify any security group. What is the default behavior regarding network access?

A The instance is launched with the default security group of the VPC, allowing inbound traffic only from other instances in the same group.

B The instance is launched with no security group, so all inbound and outbound traffic is blocked.

C The instance is launched with a security group that allows all inbound and outbound traffic.

D The instance launch fails because a security group must be specified.

💡 Hint

Think about what AWS does automatically if you don't specify a security group.

If you don't specify a security group, AWS assigns the default security group of the VPC to the instance. This group allows inbound traffic only from other instances in the same group and allows all outbound traffic.

❓ Configuration

intermediate

Which option correctly specifies a user data script to install Apache on an EC2 instance at launch?

You want to launch an EC2 instance and automatically install Apache web server using user data. Which user data script is correctly formatted for Amazon Linux 2?

A

sudo yum update -y
sudo yum install httpd -y
sudo systemctl start httpd
sudo systemctl enable httpd

B

#!/bin/bash
sudo yum update -y
sudo yum install httpd -y
sudo systemctl start httpd
sudo systemctl enable httpd

C

#!/bin/sh
sudo apt-get update
sudo apt-get install apache2 -y
sudo systemctl start apache2
sudo systemctl enable apache2

D

#!/bin/bash
sudo yum update
sudo yum install httpd
sudo service httpd start
sudo chkconfig httpd on

💡 Hint

Amazon Linux 2 uses yum and systemctl commands. The script must start with a shebang line.

The correct user data script starts with #!/bin/bash and uses yum to install Apache, then uses systemctl to start and enable the service. Option B matches this exactly.

❓ Architecture

advanced

You want to launch an EC2 instance that is accessible only from your office IP and can access the internet for updates. Which architecture setup is correct?

Choose the correct architecture to meet these requirements:

• EC2 instance accessible only from your office IP address.
• Instance can access the internet to download updates.
• Instance is in a private subnet.

A Place the instance in a private subnet with a NAT Gateway configured in a public subnet. Configure the security group to allow inbound traffic only from your office IP.

B Place the instance in a public subnet with an internet gateway. Configure the security group to allow inbound traffic only from your office IP.

C Place the instance in a private subnet with no NAT Gateway. Configure the security group to allow inbound traffic only from your office IP.

D Place the instance in a public subnet with a NAT Gateway. Configure the security group to allow inbound traffic from anywhere.

💡 Hint

Think about how instances in private subnets access the internet and how to restrict inbound access.

Instances in private subnets cannot access the internet directly. A NAT Gateway in a public subnet allows outbound internet access. Security groups restrict inbound traffic. Option A meets all requirements.

❓ security

advanced

What is the effect of launching an EC2 instance with an IAM role that has S3 read-only permissions?

You launch an EC2 instance and assign it an IAM role with permissions to read objects from S3 buckets. What is the expected behavior?

A The EC2 instance cannot access S3 buckets unless AWS credentials are manually configured on the instance.

B The EC2 instance can write to S3 buckets but cannot read objects.

C The EC2 instance can access and read objects from S3 buckets allowed by the IAM role without needing AWS credentials on the instance.

D The EC2 instance can access S3 buckets only if the security group allows outbound HTTP traffic.

💡 Hint

Consider how IAM roles provide permissions to EC2 instances.

IAM roles assigned to EC2 instances provide temporary credentials automatically. This allows the instance to access AWS services like S3 according to the role's permissions without manual credential management.

✅ Best Practice

expert

Which approach best ensures high availability for a web application running on EC2 instances?

You want to deploy a web application on EC2 instances with high availability and fault tolerance. Which setup follows AWS best practices?

A Deploy EC2 instances in multiple regions without a load balancer and manually distribute traffic.

B Deploy a single large EC2 instance in one Availability Zone with Elastic IP for static access.

C Deploy multiple EC2 instances in a single Availability Zone behind a Network Load Balancer without Auto Scaling.

D Deploy multiple EC2 instances across multiple Availability Zones behind an Elastic Load Balancer with Auto Scaling configured.

💡 Hint

Think about distributing load and handling failures automatically.

Using multiple instances across Availability Zones with a load balancer and Auto Scaling ensures the application remains available if one instance or zone fails and can handle traffic changes automatically.