Why EC2 matters for compute in AWS - Visual Breakdown

Process Flow - Why EC2 matters for compute

User needs computing power

↓

Choose EC2 service

↓

Select instance type (CPU, RAM)

↓

Launch virtual server

↓

Run applications on EC2

↓

Scale up/down as needed

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Pay only for used compute

This flow shows how a user picks EC2 to get computing power, launches a virtual server, runs apps, and scales while paying only for what they use.

Execution Sample

AWS

Launch EC2 instance with t3.micro
Run web server on EC2
Scale instance count
Stop instance when done

This example shows starting a small EC2 server, running a web app, adjusting capacity, and stopping to save cost.

Process Table

Step	Action	EC2 State	Compute Available	Cost Impact
1	User requests EC2 instance	No instances running	0 vCPUs, 0 RAM	$0
2	EC2 launches t3.micro instance	1 instance running	2 vCPUs, 1 GiB RAM	Small hourly cost
3	User deploys web server	Instance running	2 vCPUs, 1 GiB RAM	Cost continues
4	User scales to 3 instances	3 instances running	6 vCPUs, 3 GiB RAM	Cost triples
5	User stops all instances	No instances running	0 vCPUs, 0 RAM	Cost returns to $0

💡 User stops instances, so no compute is running and no cost is incurred.

Status Tracker

Variable	Start	After Step 2	After Step 4	After Step 5
Instances Running	0	1	3	0
Total vCPUs	0	2	6	0
Total RAM (GiB)	0	1	3	0
Hourly Cost	$0	Small	Triple Small	$0

Key Moments - 3 Insights

Why does cost increase when scaling instances?

Because each EC2 instance uses compute resources billed hourly, so more instances mean more cost as shown in execution_table step 4.

Does EC2 keep charging when instances are stopped?

No, as shown in execution_table step 5, stopping instances releases compute and stops billing.

Why choose EC2 instead of a physical server?

EC2 lets you quickly get compute power without buying hardware, and you pay only for what you use, shown by the flow from step 1 to 5.

Visual Quiz - 3 Questions

Look at the execution_table, how many vCPUs are available after step 4?

A 2 vCPUs

B 3 vCPUs

C 6 vCPUs

D 0 vCPUs

💡 Hint

Check the 'Compute Available' column at step 4 in execution_table.

At which step does the cost return to zero?

A Step 2

B Step 5

C Step 3

D Step 4

💡 Hint

Look at the 'Cost Impact' column in execution_table for when cost is $0.

If the user launches 5 instances instead of 3 at step 4, what happens to the total RAM?

A 5 GiB RAM

B 3 GiB RAM

C 1 GiB RAM

D 0 GiB RAM

💡 Hint

Each instance has 1 GiB RAM; multiply by number of instances in variable_tracker.

Concept Snapshot

EC2 provides virtual servers (instances) for compute.
Choose instance type based on CPU and RAM needs.
Launch instances to run apps and scale as needed.
Pay only for running instances by the hour.
Stop instances to save cost when not in use.

Full Transcript

EC2 matters for compute because it lets users quickly get virtual servers with chosen CPU and RAM. Users launch instances to run applications and can scale the number of instances up or down. They pay hourly only for the compute they use. When instances are stopped, billing stops. This flexibility and pay-as-you-go model make EC2 a key service for cloud computing.

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