Instance types and families in AWS - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding AWS Instance Families

Which AWS instance family is best suited for applications that require high CPU performance but moderate memory?

A Compute Optimized (C series)

B General Purpose (T, M series)

C Storage Optimized (I, D series)

D Memory Optimized (R, X series)

💡 Hint

Think about which family focuses on CPU power rather than memory or storage.

Compute Optimized instances (C series) provide high CPU performance with moderate memory, ideal for CPU-bound applications.

❓ Architecture

intermediate

Choosing Instance Types for a Web Application

You are designing a web application that needs balanced CPU, memory, and network performance. Which instance family should you choose?

A Storage Optimized (I series)

B Compute Optimized (C series)

C Memory Optimized (R series)

D General Purpose (M series)

💡 Hint

Look for the family designed for balanced resource needs.

General Purpose instances (M series) provide a balanced mix of CPU, memory, and network resources, suitable for web applications.

❓ service_behavior

advanced

Impact of Using Burstable Instances

What happens when a burstable instance (T series) uses all its CPU credits?

A The instance is terminated and must be restarted manually.

B The instance shuts down automatically to save costs.

C The instance continues running at baseline CPU performance until credits are replenished.

D The instance performance increases beyond baseline using on-demand credits without limits.

💡 Hint

Consider how burstable instances manage CPU usage over time.

When burstable instances use all CPU credits, they continue running but only at baseline CPU performance until credits accumulate again.

❓ security

advanced

Security Considerations for Instance Families

Which instance family should you avoid for sensitive workloads that require dedicated hardware to reduce the risk of noisy neighbors?

A General Purpose (T series)

B Dedicated Hosts

C Compute Optimized (C series)

D Memory Optimized (R series)

💡 Hint

Think about which instances share hardware with others by default.

General Purpose T series instances are burstable and run on shared hardware, which may expose sensitive workloads to noisy neighbors. Dedicated Hosts provide isolated hardware.

✅ Best Practice

expert

Optimizing Cost and Performance with Instance Families

You have a batch processing job that runs for a few hours daily and requires high memory but can tolerate interruptions. Which instance family and purchasing option combination is best?

A Compute Optimized (C series) with Reserved instances

B Memory Optimized (R series) with Spot instances

C Memory Optimized (R series) with On-Demand instances

D General Purpose (M series) with Dedicated Hosts

💡 Hint

Consider cost savings and tolerance for interruptions.

Spot instances offer significant cost savings but can be interrupted. Memory Optimized R series fits high memory needs. This combination suits batch jobs that tolerate interruptions.

Practice

1. Which AWS instance family is best suited for general purpose workloads like web servers and small databases?

easy

A. C family (e.g., c5, c6g)

B. P family (e.g., p3, p4)

C. R family (e.g., r5, r6g)

D. T family (e.g., t3, t4g)

Solution

1. Step 1: Understand instance family purposes

   The T family is designed for general purpose workloads with balanced CPU and memory.

2. Step 2: Match workload type to instance family

   Web servers and small databases typically need balanced resources, fitting T family well.

3. Final Answer:

   T family (e.g., t3, t4g) -> Option D

4. Quick Check:

   General purpose = T family [OK]

Hint: General purpose = T family instances [OK]

Common Mistakes:

• Confusing compute-optimized C family for general purpose
• Choosing memory-optimized R family for small databases
• Selecting GPU P family for simple web servers

2. Which of the following is the correct syntax to specify a compute-optimized instance type in AWS?

easy

A. t3.large

B. c5.large

C. r5.large

D. m5.large

Solution

1. Step 1: Identify compute-optimized prefix

   Compute-optimized instances start with 'c' (e.g., c5, c6g).

2. Step 2: Check instance type format

   Correct format is family + size, like 'c5.large'.

3. Final Answer:

   c5.large -> Option B

4. Quick Check:

   Compute-optimized = c5.large [OK]

Hint: Compute-optimized instances start with 'c' [OK]

Common Mistakes:

• Choosing m5.large which is general purpose
• Selecting r5.large which is memory optimized
• Using t3.large which is burstable general purpose

3. Given the following instance types, which one provides the highest memory capacity per vCPU?

A) m5.large
B) c5.large
C) r5.large
D) t3.large

medium

A. r5.large

B. c5.large

C. m5.large

D. t3.large

Solution

1. Step 1: Understand instance family memory focus

   R family is memory optimized, offering more memory per vCPU than others.

2. Step 2: Compare memory per vCPU for given types

   r5.large has 16 GiB RAM and 2 vCPUs (8 GiB/vCPU), higher than m5.large (8 GiB/2 vCPU = 4 GiB/vCPU), c5.large (4 GiB/2 vCPU = 2 GiB/vCPU), t3.large (8 GiB/2 vCPU = 4 GiB/vCPU).

3. Final Answer:

   r5.large -> Option A

4. Quick Check:

   Memory optimized = r5.large [OK]

Hint: Memory optimized = R family (r5, r6g) [OK]

Common Mistakes:

• Assuming m5.large has more memory per vCPU
• Confusing compute-optimized c5.large as memory heavy
• Thinking burstable t3.large has highest memory per vCPU

4. You launched an instance with type c5.large but your application needs more memory. Which instance type should you choose to fix this issue without changing the CPU count?

medium

A. r5.large

B. c5.xlarge

C. t3.large

D. m5.large

Solution

1. Step 1: Identify current instance specs

   c5.large has 2 vCPUs and 4 GiB memory.

2. Step 2: Find instance with same vCPU but more memory

   r5.large has 2 vCPUs and 16 GiB memory, increasing memory without changing CPU count.

3. Final Answer:

   r5.large -> Option A

4. Quick Check:

   More memory, same CPU = r5.large [OK]

Hint: Keep vCPU same, pick memory-optimized with same size [OK]

Common Mistakes:

• Choosing c5.xlarge which doubles CPU and memory
• Picking t3.large which is burstable, not memory optimized
• Selecting m5.large which has less memory (8 GiB) than r5.large

5. You need to run a machine learning training job that requires high GPU performance and large memory. Which instance family and size combination is the best fit?

hard

A. r5.12xlarge

B. c5.4xlarge

C. p4d.24xlarge

D. t3.2xlarge

Solution

1. Step 1: Identify instance families for GPU workloads

   P family instances are designed for GPU-intensive tasks like machine learning.

2. Step 2: Choose size with high GPU and memory

   p4d.24xlarge offers multiple GPUs and large memory, ideal for training jobs.

3. Final Answer:

   p4d.24xlarge -> Option C

4. Quick Check:

   GPU + large memory = p4d.24xlarge [OK]

Hint: GPU needs = P family, largest size for training [OK]

Common Mistakes:

• Picking c5.4xlarge which lacks GPUs
• Choosing r5.12xlarge which is memory optimized but no GPU
• Selecting t3.2xlarge which is burstable general purpose