Fargate serverless containers in AWS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to specify the launch type for an ECS task using Fargate.

AWS

LaunchType=[1]

Drag options to blanks, or click blank then click option'

AFARGATE

BEC2

CLAMBDA

DON_DEMAND

Attempts:

3 left

💡 Hint

Common Mistakes

Using EC2 launch type instead of Fargate

Confusing Lambda with Fargate

The launch type FARGATE tells ECS to run the container without managing servers.

2fill in blank

medium

Complete the code to define the network mode required for Fargate tasks.

AWS

"networkMode": "[1]"

Drag options to blanks, or click blank then click option'

Aawsvpc

Bbridge

Chost

Dnone

Attempts:

3 left

💡 Hint

Common Mistakes

Using bridge or host network mode which are for EC2 launch type

Setting network mode to none

Fargate requires the awsvpc network mode to assign each task its own elastic network interface.

3fill in blank

hard

Fix the error in the task definition to specify CPU units for a Fargate task.

AWS

"cpu": "[1]"

Drag options to blanks, or click blank then click option'

A1024

B5120

C2048

D256

Attempts:

3 left

💡 Hint

Common Mistakes

Using CPU values not supported by Fargate

Using values too large or invalid strings

Fargate CPU values must be one of the allowed values like 256, 512, 1024, etc. 256 is the smallest valid CPU unit.

4fill in blank

hard

Fill both blanks to define memory and CPU for a Fargate task in the task definition.

AWS

"memory": "[1]",
"cpu": "[2]"

Drag options to blanks, or click blank then click option'

A512

B256

C1024

D2048

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing incompatible CPU and memory values

Using memory less than 512 MB

Memory and CPU must be valid Fargate values. Here, 512 MB memory and 256 CPU units are a valid combination.

5fill in blank

hard

Fill all three blanks to configure container port mapping and protocol for a Fargate service.

AWS

"portMappings": [{
  "containerPort": [1],
  "hostPort": [2],
  "protocol": "[3]"
}]

Drag options to blanks, or click blank then click option'

A80

B0

Ctcp

Dudp

Attempts:

3 left

💡 Hint

Common Mistakes

Setting hostPort equal to containerPort in Fargate

Using UDP protocol for HTTP services

For Fargate, hostPort must be 0 to allow dynamic assignment. Container port 80 is common for HTTP. Protocol is usually TCP.

Practice

1. What is the main benefit of using AWS Fargate for running containers?

easy

A. You have to configure virtual machines yourself.

B. You must manually scale the containers.

C. You need to install and maintain the operating system.

D. You don't need to manage servers or clusters.

Solution

1. Step 1: Understand Fargate's serverless nature

   AWS Fargate runs containers without requiring you to manage the underlying servers or clusters.

2. Step 2: Compare options

   The other options describe manual management tasks that Fargate removes for you.

3. Final Answer:

   You don't need to manage servers or clusters. -> Option D

4. Quick Check:

   Serverless container management = A [OK]

Hint: Fargate means no server management needed [OK]

Common Mistakes:

• Thinking you must manage servers manually
• Confusing Fargate with EC2 instances
• Assuming you handle OS updates

2. Which of the following is the correct way to specify CPU and memory for a Fargate task definition?

easy

A. "cpu": 512, "memory": 1024

B. "cpu": "512", "memory": "1024"

C. "cpu": "0.5", "memory": "1GB"

D. "cpu": "512MB", "memory": "1GB"

Solution

1. Step 1: Check Fargate task definition format

   Fargate expects CPU and memory as strings representing CPU units and MiB memory, e.g., "512" and "1024".

2. Step 2: Evaluate options

   "cpu": "512", "memory": "1024" uses strings with numeric values, which is correct. Using numbers instead of strings is incorrect. Decimal values for CPU or units like GB/MB are invalid.

3. Final Answer:

   "cpu": "512", "memory": "1024" -> Option B

4. Quick Check:

   CPU and memory as strings = B [OK]

Hint: CPU and memory must be strings in task definition [OK]

Common Mistakes:

• Using numbers instead of strings
• Adding units like MB or GB
• Using decimal numbers for CPU

3. Given this Fargate task definition snippet:

{"cpu": "256", "memory": "512", "containerDefinitions": [{"name": "app", "image": "myapp:latest"}]}

What happens if you try to run this task with 1024 MiB memory requested in the service?

medium

A. The task runs with 512 MiB memory as defined in the task.

B. The task runs but may be terminated if it exceeds 512 MiB.

C. The task fails to start due to memory mismatch.

D. The service overrides the task memory to 1024 MiB automatically.

Solution

1. Step 1: Understand memory settings in Fargate

   Memory is defined in the task definition and must match the service configuration; mismatches cause failures.

2. Step 2: Analyze the mismatch

   The task requests 512 MiB, but the service requests 1024 MiB, causing a conflict and preventing the task from starting.

3. Final Answer:

   The task fails to start due to memory mismatch. -> Option C

4. Quick Check:

   Memory mismatch causes failure = D [OK]

Hint: Task and service memory must match exactly [OK]

Common Mistakes:

• Assuming service overrides task memory
• Thinking task runs with lower memory
• Ignoring mismatch errors

4. You created a Fargate service but the tasks keep failing with "RESOURCE:MEMORY" errors. What is the most likely cause?

medium

A. The task definition requests more memory than the Fargate platform allows.

B. The container image is missing from the registry.

C. The service is not attached to a load balancer.

D. The CPU units are set too high.

Solution

1. Step 1: Understand RESOURCE:MEMORY errors

   This error means the task requested more memory than available or allowed by Fargate limits.

2. Step 2: Evaluate other options

   Missing images cause different errors, load balancer issues don't cause memory errors, and CPU settings affect CPU, not memory.

3. Final Answer:

   The task definition requests more memory than the Fargate platform allows. -> Option A

4. Quick Check:

   Memory error means memory request too high = C [OK]

Hint: Memory errors usually mean request exceeds limits [OK]

Common Mistakes:

• Blaming missing container images
• Confusing CPU and memory errors
• Ignoring platform memory limits

5. You want to run a web app on Fargate that needs 2 containers: one for the app and one for logging. How should you configure the task definition to ensure both containers run together and share CPU and memory?

hard

A. Define both containers in the same task definition with combined CPU and memory settings.

B. Create two separate task definitions and run two Fargate services.

C. Run one container on Fargate and the other on EC2 instances.

D. Use one container and add logging as a sidecar process inside it.

Solution

1. Step 1: Understand multi-container tasks in Fargate

   Fargate supports multiple containers in one task definition sharing CPU and memory.

2. Step 2: Evaluate options for running two containers together

   Defining both containers in the same task definition with combined CPU and memory settings ensures they run together and share resources. Separating into different task definitions or services loses shared resource benefits and co-location. Adding logging as a sidecar process inside the app mixes concerns, which is not best practice.

3. Final Answer:

   Define both containers in the same task definition with combined CPU and memory settings. -> Option A

4. Quick Check:

   Multi-container task = single task definition with both containers [OK]

Hint: Use one task definition for multiple containers sharing resources [OK]

Common Mistakes:

• Splitting containers into separate tasks unnecessarily
• Mixing logging inside app container
• Running containers on different platforms