Why EC2 matters for compute in AWS - Challenge Your Understanding

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the primary benefit of using EC2 for compute?

Imagine you want to run a website. Why would you choose EC2 instead of your own computer?

A EC2 lets you rent virtual computers that can run your website anytime, without needing your own hardware.

B EC2 is a storage service that keeps your website files safe.

C EC2 automatically writes your website code for you.

D EC2 is a tool to design website graphics.

💡 Hint

Think about what you need to run a website 24/7 without buying a physical machine.

EC2 provides virtual servers you can use anytime, so you don't need to own or manage physical computers.

❓ Architecture

intermediate

Which EC2 feature helps you handle sudden traffic spikes?

You run an online store. Sometimes many people visit at once. Which EC2 feature helps your site stay fast?

A Elastic Load Balancer to spread traffic across multiple EC2 instances.

B EC2 Snapshots to save your data.

C EC2 Key Pairs to secure your login.

D EC2 Placement Groups to store files.

💡 Hint

Think about how to share work among many computers to avoid overload.

Elastic Load Balancer distributes incoming traffic to multiple EC2 instances, helping handle more visitors smoothly.

❓ security

advanced

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

You start an EC2 server but forget to assign a security group. What is the result?

A The instance will be open to the internet with no restrictions.

B The instance will automatically get a default security group.

C The instance will have no network access, blocking all inbound and outbound traffic.

D The instance will fail to launch.

💡 Hint

Security groups act like firewalls. What if none is set?

If you don't specify a security group when launching, the instance is automatically associated with the default security group for the VPC.

❓ service_behavior

advanced

How does EC2 Auto Scaling respond when CPU usage is high?

Your EC2 Auto Scaling group monitors CPU usage. When usage goes above 80%, what happens?

A It sends an alert but takes no action.

B It shuts down existing instances to save costs.

C It launches new EC2 instances to share the workload and reduce CPU usage.

D It automatically upgrades the CPU on existing instances.

💡 Hint

Think about how to keep performance steady when demand grows.

Auto Scaling adds more EC2 instances when CPU usage is high to handle more work smoothly.

✅ Best Practice

expert

Which practice improves EC2 cost efficiency for steady workloads?

You run a steady application on EC2 24/7. Which option best reduces your costs?

A Keep instances running without monitoring usage.

B Use On-Demand Instances only when traffic spikes.

C Launch Spot Instances without interruption handling.

D Purchase Reserved Instances to get a lower hourly rate for long-term use.

💡 Hint

Think about paying less when you know you will use the server for a long time.

Reserved Instances offer a discount for committing to use EC2 over a period, saving money for steady workloads.

Practice

1. What is the main benefit of using Amazon EC2 for computing tasks?

easy

A. It automatically writes code for your applications.

B. It stores large amounts of data permanently.

C. It manages your email communications.

D. It provides virtual servers that you can start and stop anytime.

Solution

1. Step 1: Understand EC2's purpose

   EC2 offers virtual computers (servers) in the cloud that you can control.

2. Step 2: Identify the key feature

   You can launch, stop, and scale these virtual servers anytime as needed.

3. Final Answer:

   It provides virtual servers that you can start and stop anytime. -> Option D

4. Quick Check:

   EC2 = virtual servers you control [OK]

Hint: EC2 = virtual computers you can manage anytime [OK]

Common Mistakes:

• Confusing EC2 with storage services
• Thinking EC2 writes code automatically
• Mixing EC2 with email or messaging services

2. Which of the following is the correct way to describe an EC2 instance?

easy

A. A virtual server you can launch in the cloud.

B. A database service for storing records.

C. A software tool for editing documents.

D. A physical server you buy and install in your office.

Solution

1. Step 1: Define EC2 instance

   An EC2 instance is a virtual server running in the cloud, not a physical machine.

2. Step 2: Match description

   A virtual server you can launch in the cloud. correctly states it is a virtual server you can launch anytime.

3. Final Answer:

   A virtual server you can launch in the cloud. -> Option A

4. Quick Check:

   EC2 instance = virtual cloud server [OK]

Hint: EC2 instance = virtual server, not physical [OK]

Common Mistakes:

• Thinking EC2 is a physical server
• Confusing EC2 with software tools
• Mixing EC2 with database services

3. Consider this scenario: You launch an EC2 instance, run a compute-heavy task, then stop the instance. What happens to the compute power and billing?

medium

A. Compute power stops and billing stops when the instance is stopped.

B. Compute power continues but billing stops when the instance is stopped.

C. Compute power stops but billing continues when the instance is stopped.

D. Compute power and billing continue even if the instance is stopped.

Solution

1. Step 1: Understand EC2 instance stop behavior

   When you stop an EC2 instance, the virtual server stops running, so compute power is no longer used.

2. Step 2: Understand billing during stop

   Billing for compute stops because you are not using the server, though storage may still be billed separately.

3. Final Answer:

   Compute power stops and billing stops when the instance is stopped. -> Option A

4. Quick Check:

   Stopped instance = no compute, no billing [OK]

Hint: Stop instance = stop compute and billing [OK]

Common Mistakes:

• Assuming billing continues after stopping
• Thinking compute runs when stopped
• Confusing storage billing with compute billing

4. You tried to launch an EC2 instance but got an error saying your account has reached the instance limit. What should you do to fix this?

medium

A. Change the instance type to a larger size.

B. Delete your AWS account and create a new one.

C. Request a limit increase from AWS support.

D. Restart your computer and try again.

Solution

1. Step 1: Identify the cause of the error

   A limit error means your AWS account has a maximum number of instances allowed, which you reached.

2. Step 2: Find the correct fix

   You can request AWS to increase this limit by contacting support, which is the proper solution.

3. Final Answer:

   Request a limit increase from AWS support. -> Option C

4. Quick Check:

   Instance limit error = request increase [OK]

Hint: Limit errors need AWS support request [OK]

Common Mistakes:

• Deleting account unnecessarily
• Changing instance size won't fix limits
• Restarting computer does not affect AWS limits

5. You want to run a web application that needs to handle sudden traffic spikes without delay. How does EC2 help you achieve this?

hard

A. By automatically writing code to optimize your app.

B. By letting you quickly launch more instances to add compute power as needed.

C. By storing all your data in a single large server.

D. By sending emails to users when traffic spikes.

Solution

1. Step 1: Understand traffic spikes and compute needs

   Sudden traffic spikes require more computing power to handle extra users smoothly.

2. Step 2: How EC2 supports scaling

   EC2 allows you to launch more virtual servers quickly, adding compute power to meet demand.

3. Final Answer:

   By letting you quickly launch more instances to add compute power as needed. -> Option B

4. Quick Check:

   EC2 enables fast scaling for traffic spikes [OK]

Hint: EC2 lets you add servers fast for traffic spikes [OK]

Common Mistakes:

• Thinking EC2 writes code automatically
• Confusing compute scaling with data storage
• Assuming EC2 manages emails for traffic