ECS cluster concept in AWS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define an ECS cluster name.

AWS

resource "aws_ecs_cluster" "example" {
  name = "[1]"
}

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

Aexample-cluster

Bmy-ecs-cluster

Ccluster-01

Ddefault-cluster

Attempts:

3 left

💡 Hint

Common Mistakes

Leaving the name empty or using invalid characters.

Using a name that is too generic or unclear.

The ECS cluster name is set to "example-cluster" as a clear identifier.

2fill in blank

medium

Complete the code to enable container insights on the ECS cluster.

AWS

resource "aws_ecs_cluster" "example" {
  name = "example-cluster"
  [1] = true
}

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

Amonitoring

Bsetting

Ccontainer_insights

Denable_logging

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect attribute names like 'enable_logging' or 'monitoring'.

Forgetting to set the value to true.

The correct attribute to enable container insights is container_insights.

3fill in blank

hard

Fix the error in the ECS cluster resource by completing the missing attribute.

AWS

resource "aws_ecs_cluster" "example" {
  name = "example-cluster"
  [1] = "ENABLED"
}

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

Acontainer_insights

Blogging

Cmonitoring

Dinsights

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect attribute names or values.

Using boolean true instead of string "ENABLED".

The attribute container_insights accepts the value "ENABLED" to turn on insights.

4fill in blank

hard

Fill both blanks to create an ECS cluster with container insights enabled and a custom name.

AWS

resource "aws_ecs_cluster" "example" {
  name = "[1]"
  [2] = true
}

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

Acustom-cluster

Benable_logging

Ccontainer_insights

Dmonitoring

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up attribute names or using incorrect values.

Using generic names instead of a custom cluster name.

The cluster name is set to "custom-cluster" and container_insights is enabled with true.

5fill in blank

hard

Fill all three blanks to define an ECS cluster with a custom name, enable container insights, and add tags.

AWS

resource "aws_ecs_cluster" "example" {
  name = "[1]"
  [2] = true
  tags = {
    Environment = "[3]"
  }
}

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

Aprod-cluster

Bcontainer_insights

Cproduction

Dmonitoring

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect attribute names or tag values.

Forgetting to enable container insights.

The cluster is named "prod-cluster", container insights are enabled, and the tag Environment is set to "production".

Practice

1. What is the main purpose of an ECS cluster in AWS?

easy

A. To group and manage servers that run containerized applications

B. To store data in a database

C. To create virtual machines

D. To monitor network traffic

Solution

1. Step 1: Understand ECS cluster role

   An ECS cluster is a collection of servers (called container instances) that run containerized apps.

2. Step 2: Identify main function

   It helps manage and scale containers by grouping these servers together.

3. Final Answer:

   To group and manage servers that run containerized applications -> Option A

4. Quick Check:

   ECS cluster = group servers for containers [OK]

Hint: ECS clusters group servers for containers [OK]

Common Mistakes:

• Confusing ECS cluster with database storage
• Thinking ECS cluster creates virtual machines
• Assuming ECS cluster monitors network traffic

2. Which AWS CLI command is used to create a new ECS cluster?

easy

A. aws ecs create-cluster --cluster-name MyCluster

B. aws ec2 create-cluster --name MyCluster

C. aws s3 create-bucket --bucket MyCluster

D. aws ecs start-cluster --name MyCluster

Solution

1. Step 1: Identify correct service and command

   The ECS service uses aws ecs create-cluster to create clusters.

2. Step 2: Check command syntax

   The correct syntax includes --cluster-name to name the cluster.

3. Final Answer:

   aws ecs create-cluster --cluster-name MyCluster -> Option A

4. Quick Check:

   Create ECS cluster = aws ecs create-cluster [OK]

Hint: Use 'aws ecs create-cluster' to make ECS clusters [OK]

Common Mistakes:

• Using EC2 or S3 commands instead of ECS
• Using 'start-cluster' which is not a valid command
• Incorrect parameter names like --name instead of --cluster-name

3. Given this AWS CLI output snippet after creating an ECS cluster:

{
  "cluster": {
    "clusterName": "TestCluster",
    "status": "ACTIVE",
    "registeredContainerInstancesCount": 0
  }
}

What does the registeredContainerInstancesCount value of 0 mean?

medium

A. The cluster is inactive and cannot run tasks

B. No container instances (servers) have joined the cluster yet

C. The cluster has one container instance running

D. The cluster is full and cannot accept more instances

Solution

1. Step 1: Understand the field meaning

   registeredContainerInstancesCount shows how many servers have joined the cluster.

2. Step 2: Interpret the value 0

   A value of 0 means no servers have registered yet to run containers.

3. Final Answer:

   No container instances (servers) have joined the cluster yet -> Option B

4. Quick Check:

   Count 0 = no servers joined [OK]

Hint: Count 0 means no servers joined cluster yet [OK]

Common Mistakes:

• Thinking 0 means cluster is inactive
• Assuming 0 means one instance is running
• Believing 0 means cluster is full

4. You tried to run a task on your ECS cluster but got an error saying no container instances available. What is the most likely cause?

medium

A. Your AWS CLI version is outdated

B. Your cluster name is misspelled in the task definition

C. Your task definition is missing a container image

D. You have not registered any container instances to the cluster

Solution

1. Step 1: Analyze the error message

   Error about no container instances means no servers are ready to run tasks.

2. Step 2: Identify common cause

   This usually happens if no container instances have joined the ECS cluster yet.

3. Final Answer:

   You have not registered any container instances to the cluster -> Option D

4. Quick Check:

   No container instances = cannot run tasks [OK]

Hint: No container instances means tasks cannot run [OK]

Common Mistakes:

• Blaming misspelled cluster name without checking instances
• Assuming task definition errors cause this specific message
• Thinking AWS CLI version affects cluster instance availability

5. You want to run multiple containerized apps on a single ECS cluster and ensure they scale automatically. Which combination of AWS features should you use?

hard

A. Use only AWS Lambda functions without ECS clusters

B. Create multiple ECS clusters, each with one container instance, no scaling

C. Create one ECS cluster, register container instances, use ECS Service with Auto Scaling

D. Create an ECS cluster and manually add containers without scaling

Solution

1. Step 1: Understand ECS cluster scaling

   A single ECS cluster can run many container instances and apps together.

2. Step 2: Use ECS Service with Auto Scaling

   ECS Service manages running tasks and can scale containers automatically based on demand.

3. Step 3: Combine cluster, instances, and auto scaling

   Register container instances to the cluster and configure ECS Service Auto Scaling for automatic scaling.

4. Final Answer:

   Create one ECS cluster, register container instances, use ECS Service with Auto Scaling -> Option C

5. Quick Check:

   Cluster + instances + ECS Service Auto Scaling = scalable apps [OK]

Hint: Use ECS Service Auto Scaling on one cluster for scaling apps [OK]

Common Mistakes:

• Creating multiple clusters unnecessarily
• Ignoring ECS Service Auto Scaling feature
• Using Lambda instead of ECS for container apps
• Manually scaling containers without automation