Cost optimization pillar in AWS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main goal of the Cost Optimization pillar in cloud architecture?

The main goal is to use cloud resources efficiently to reduce costs while maintaining performance and reliability.

beginner

Name one common strategy to reduce cloud costs.

One common strategy is to use reserved instances or savings plans to get discounts for long-term usage.

beginner

Why is monitoring cloud usage important for cost optimization?

Monitoring helps identify unused or underused resources so you can stop or resize them to save money.

intermediate

What does 'right-sizing' mean in the context of cost optimization?

Right-sizing means choosing the right size and type of cloud resources to match your actual needs without overspending.

intermediate

How can automation help with cost optimization?

Automation can turn off resources when not needed and scale resources automatically to avoid paying for unused capacity.

Which AWS service helps track and analyze your cloud spending?

A Amazon EC2

B Amazon S3

C AWS Cost Explorer

D AWS Lambda

AWS Cost Explorer provides tools to visualize and manage your AWS costs and usage.

What is a benefit of using reserved instances in AWS?

A Unlimited storage

B Lower cost for long-term usage

C Automatic backups

D Faster network speed

Reserved instances offer significant discounts compared to on-demand pricing when you commit to use for a period.

What does 'right-sizing' help prevent?

A Security breaches

B Data loss

C Slow internet

D Overpaying for resources you don't need

Right-sizing ensures you only pay for the resources that fit your actual workload.

Which action can reduce costs by stopping resources when not in use?

A Automation

B Manual backups

C Increasing storage

D Adding more users

Automation can schedule stopping or scaling down resources to save money during idle times.

Why should you regularly review your cloud usage?

A To find and remove unused resources

B To increase costs

C To add more users

D To slow down performance

Regular reviews help identify resources that are no longer needed, reducing unnecessary spending.

Explain the key strategies used in the Cost Optimization pillar to reduce cloud expenses.

Think about how to avoid paying for unused or oversized resources.

Describe how automation can help maintain cost efficiency in cloud environments.

Consider how machines can manage resources better than humans for cost savings.

Practice

1. Which AWS tool helps you understand and analyze your cloud spending over time?

easy

A. EC2 Dashboard

B. CloudTrail

C. Cost Explorer

D. IAM

Solution

1. Step 1: Identify AWS tools for cost management

   Cost Explorer is designed to analyze and visualize AWS spending over time.

2. Step 2: Compare other tools' purposes

   CloudTrail tracks API calls, EC2 Dashboard manages instances, IAM manages access, none focus on cost analysis.

3. Final Answer:

   Cost Explorer -> Option C

4. Quick Check:

   Cost analysis tool = Cost Explorer [OK]

Hint: Cost Explorer = spending analysis tool [OK]

Common Mistakes:

• Confusing CloudTrail with cost tool
• Thinking EC2 Dashboard shows costs
• Mixing IAM with billing

2. Which of the following is the correct AWS pricing option to save costs for steady-state workloads?

easy

A. On-Demand Instances

B. Reserved Instances

C. Spot Instances

D. Dedicated Hosts

Solution

1. Step 1: Understand pricing options

   Reserved Instances offer a discount for long-term, steady workloads by committing to usage.

2. Step 2: Compare other options

   On-Demand is pay-as-you-go, Spot is for interruptible workloads, Dedicated Hosts are costly physical servers.

3. Final Answer:

   Reserved Instances -> Option B

4. Quick Check:

   Steady workload savings = Reserved Instances [OK]

Hint: Reserved = save on steady workloads [OK]

Common Mistakes:

• Choosing On-Demand for savings
• Using Spot for steady workloads
• Confusing Dedicated Hosts with cost-saving

3. Consider this AWS Lambda function usage pattern: it runs 1000 times per day, each execution lasts 1 second, and uses 128 MB memory. Which change will reduce cost the most?

medium

A. Increase memory to 512 MB to reduce execution time

B. Decrease memory to 64 MB to save memory cost

C. Increase execution time to batch more work per run

D. Keep memory at 128 MB and reduce execution time by optimizing code

Solution

1. Step 1: Understand Lambda cost factors

   Cost depends on memory size and execution duration multiplied by invocations.

2. Step 2: Evaluate options

   Increasing memory may reduce time but might increase cost; decreasing memory may increase time; optimizing code reduces time without increasing memory.

3. Final Answer:

   Keep memory at 128 MB and reduce execution time by optimizing code -> Option D

4. Quick Check:

   Optimize code to reduce time = save cost [OK]

Hint: Lower execution time saves more than just lowering memory [OK]

Common Mistakes:

• Assuming more memory always saves cost
• Reducing memory without checking time
• Increasing execution time to batch

4. You notice your AWS Trusted Advisor reports underutilized EC2 instances. What is the best immediate action to optimize cost?

medium

A. Resize instances to smaller types matching usage

B. Terminate the underutilized instances immediately

C. Ignore the report as it might be inaccurate

D. Switch all instances to Dedicated Hosts

Solution

1. Step 1: Understand Trusted Advisor recommendations

   It flags underutilized instances to help reduce waste by resizing or terminating.

2. Step 2: Choose best cost optimization action

   Resizing to smaller instances keeps service running but reduces cost; terminating immediately may disrupt service; ignoring wastes money; Dedicated Hosts are expensive.

3. Final Answer:

   Resize instances to smaller types matching usage -> Option A

4. Quick Check:

   Resize underutilized = save cost safely [OK]

Hint: Resize before terminating to avoid downtime [OK]

Common Mistakes:

• Terminating without backup
• Ignoring Trusted Advisor
• Switching to costly Dedicated Hosts

5. A company wants to reduce AWS costs by automating resource scaling and tracking spending. Which combination of AWS services best supports this goal?

hard

A. AWS Auto Scaling + AWS Budgets + AWS Cost Explorer

B. AWS CloudTrail + AWS Config + AWS IAM

C. AWS Lambda + Amazon S3 + Amazon RDS

D. Amazon EC2 + AWS Trusted Advisor + AWS CloudWatch Logs

Solution

1. Step 1: Identify services for automated scaling

   AWS Auto Scaling automatically adjusts resource capacity based on demand.

2. Step 2: Identify services for cost tracking

   AWS Budgets sets spending limits and alerts; Cost Explorer analyzes spending patterns.

3. Step 3: Evaluate other options

   CloudTrail and Config track changes and security, not cost; Lambda, S3, RDS are compute/storage services; Trusted Advisor gives recommendations but not automation; CloudWatch Logs monitor logs.

4. Final Answer:

   AWS Auto Scaling + AWS Budgets + AWS Cost Explorer -> Option A

5. Quick Check:

   Auto scale + budgets + cost explorer = cost optimization [OK]

Hint: Auto Scaling + Budgets + Cost Explorer = automate cost control [OK]

Common Mistakes:

• Confusing CloudTrail with cost tools
• Choosing unrelated services
• Ignoring automation tools