CloudWatch metrics in AWS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an Amazon CloudWatch metric?

A CloudWatch metric is a time-ordered set of data points that represent the performance or health of a resource or application, like CPU usage or request count.

beginner

How often does CloudWatch collect standard metrics by default?

CloudWatch collects standard metrics every 5 minutes by default for AWS resources.

intermediate

What is the difference between standard and custom CloudWatch metrics?

Standard metrics are automatically collected by AWS for many services. Custom metrics are user-defined data points sent to CloudWatch to monitor specific application or business data.

intermediate

What does a CloudWatch metric namespace do?

A namespace groups related metrics together, like 'AWS/EC2' for EC2 metrics or a custom namespace for your own metrics, helping organize and isolate data.

beginner

Why is it important to monitor CloudWatch metrics?

Monitoring metrics helps detect problems early, understand system performance, and make informed decisions to keep applications healthy and efficient.

How frequently are standard CloudWatch metrics collected by default?

A Every 10 minutes

B Every 5 minutes

C Every 1 minute

D Every 30 seconds

Standard metrics are collected every 5 minutes by default.

Which of the following is NOT a CloudWatch metric namespace?

A AWS/Database

B AWS/S3

C AWS/CustomApp

D AWS/EC2

'AWS/Database' is not a standard namespace; namespaces are specific to services or custom defined.

What type of data does a CloudWatch metric represent?

A Time-ordered numerical data points

B Text logs

C Configuration files

D User credentials

Metrics are numerical data points collected over time.

Who can create custom CloudWatch metrics?

A Only AWS automatically

B Only third-party tools

C Only AWS support team

D Users or applications sending data

Users or applications can send custom metrics to CloudWatch.

Why should you monitor CloudWatch metrics?

A To create user accounts

B To change AWS pricing

C To detect system issues early

D To delete AWS resources

Monitoring helps detect issues and maintain system health.

Explain what a CloudWatch metric is and why it is useful.

Think about how you check your car's speed or fuel level to know if it runs well.

Describe the difference between standard and custom CloudWatch metrics.

Standard is like factory settings; custom is like personal settings.

Practice

1. What is the primary purpose of AWS CloudWatch metrics?

easy

A. To create virtual machines

B. To store files and documents securely

C. To monitor and track the performance of cloud resources

D. To manage user permissions

Solution

1. Step 1: Understand CloudWatch metrics role

   CloudWatch metrics collect data points about cloud resources like CPU usage or network traffic.

2. Step 2: Identify the main use

   This data helps monitor and keep cloud resources healthy and efficient.

3. Final Answer:

   To monitor and track the performance of cloud resources -> Option C

4. Quick Check:

   CloudWatch metrics = Monitor resources [OK]

Hint: CloudWatch metrics = numbers about resource health [OK]

Common Mistakes:

• Confusing metrics with storage services
• Thinking metrics create resources
• Mixing metrics with user management

2. Which of the following is the correct way to specify a metric namespace in AWS CloudWatch?

easy

A. Namespace: AWS/EC2

B. Namespace = AWS-EC2

C. Namespace -> AWS.EC2

D. Namespace is AWS_EC2

Solution

1. Step 1: Recall CloudWatch namespace format

   Namespaces use a string format with a slash, like AWS/EC2, to group metrics.

2. Step 2: Check each option format

   Only 'Namespace: AWS/EC2' uses the correct slash format without invalid characters.

3. Final Answer:

   Namespace: AWS/EC2 -> Option A

4. Quick Check:

   Namespace uses slash (/) format [OK]

Hint: Namespace uses slash (/) format, not dash or underscore [OK]

Common Mistakes:

• Using dash or underscore instead of slash
• Using equal sign instead of colon
• Using arrow notation incorrectly

3. Given the following CloudWatch metric data points for CPU utilization: [10, 20, 30, 40, 50], what is the average CPU utilization reported?

medium

A. 10

B. 25

C. 50

D. 30

Solution

1. Step 1: Sum all CPU utilization values

   10 + 20 + 30 + 40 + 50 = 150

2. Step 2: Calculate average by dividing sum by count

   150 / 5 = 30

3. Final Answer:

   30 -> Option D

4. Quick Check:

   Average = Sum / Count = 30 [OK]

Hint: Average = add all values, divide by number of values [OK]

Common Mistakes:

• Adding incorrectly
• Dividing by wrong count
• Picking max or min instead of average

4. You set a CloudWatch alarm to trigger when CPU utilization exceeds 70%, but it never triggers even when CPU is 80%. What is a likely cause?

medium

A. The metric period is too long, smoothing out spikes

B. The alarm threshold is set incorrectly below 70%

C. The alarm action is missing

D. The CPU utilization metric is disabled

Solution

1. Step 1: Understand alarm threshold and metric period

   The alarm triggers if average CPU exceeds 70% during the period.

2. Step 2: Identify effect of long metric period

   A long period averages out spikes, so short CPU spikes above 70% may not trigger alarm.

3. Final Answer:

   The metric period is too long, smoothing out spikes -> Option A

4. Quick Check:

   Long period averages hide spikes [OK]

Hint: Long metric periods smooth spikes, prevent alarms [OK]

Common Mistakes:

• Assuming threshold is set below 70%
• Ignoring missing alarm actions
• Thinking metrics can be disabled

5. You want to monitor the average latency of your web application every 5 minutes using CloudWatch. Which combination of settings is best to achieve this?

hard

A. Set metric period to 60 seconds and statistic to Sum

B. Set metric period to 300 seconds and statistic to Average

C. Set metric period to 300 seconds and statistic to Maximum

D. Set metric period to 60 seconds and statistic to Minimum

Solution

1. Step 1: Understand metric period and statistic

   Period defines how often data is collected; statistic defines how data is summarized.

2. Step 2: Match requirements to settings

   To monitor average latency every 5 minutes, use 300 seconds period and Average statistic.

3. Final Answer:

   Set metric period to 300 seconds and statistic to Average -> Option B

4. Quick Check:

   5 min period + Average = correct monitoring [OK]

Hint: Use 300s period and Average for 5-minute average latency [OK]

Common Mistakes:

• Using Sum or Maximum instead of Average
• Using 60s period for 5-minute average
• Confusing Minimum with latency monitoring