CloudWatch Logs in AWS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a CloudWatch Logs log group using AWS CLI.

AWS

aws logs create-log-group --log-group-name [1]

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

AMyAppLogGroup

BMyAppStream

CMyAppAlarm

DMyAppMetricFilter

Attempts:

3 left

💡 Hint

Common Mistakes

Using a log stream name instead of a log group name.

Confusing metric filters or alarms with log groups.

The create-log-group command requires the log group name. Here, MyAppLogGroup is the correct name for the log group.

2fill in blank

medium

Complete the code to put a log event into a CloudWatch Logs log stream using AWS CLI.

AWS

aws logs put-log-events --log-group-name MyAppLogGroup --log-stream-name MyAppStream --log-events '[{"timestamp":[1],"message":"User login successful"}]'

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

A01/01/2023

B2023-01-01T12:00:00Z

C1672531200000

D12:00:00

Attempts:

3 left

💡 Hint

Common Mistakes

Using ISO date strings instead of milliseconds.

Using human-readable date formats.

The timestamp value must be in milliseconds since Unix epoch. The value 1672531200000 represents a valid timestamp.

3fill in blank

hard

Fix the error in the AWS CLI command to describe log streams for a log group.

AWS

aws logs describe-log-streams --log-group-name [1]

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

AMyAppStream

BMyAppAlarm

CMyAppMetricFilter

DMyAppLogGroup

Attempts:

3 left

💡 Hint

Common Mistakes

Using a log stream name instead of a log group name.

Confusing metric filters or alarms with log groups.

The describe-log-streams command requires the log group name, not the log stream name.

4fill in blank

hard

Fill both blanks to create a metric filter for error logs in a log group.

AWS

aws logs put-metric-filter --log-group-name [1] --filter-name ErrorFilter --metric-transformations '[{"metricName":"ErrorCount","metricNamespace":"MyApp","metricValue":[2]]' --filter-pattern "ERROR"

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

AMyAppLogGroup

B1

C0

DErrorStream

Attempts:

3 left

💡 Hint

Common Mistakes

Using a log stream name instead of a log group name.

Setting metric value to zero which would not count events.

The metric filter must be created on the log group MyAppLogGroup and the metric value for each matching event is 1.

5fill in blank

hard

Fill all three blanks to create an alarm based on the metric filter for error count.

AWS

aws cloudwatch put-metric-alarm --alarm-name [1] --metric-name [2] --namespace MyApp --statistic Sum --period 60 --threshold 5 --comparison-operator [3] --evaluation-periods 1 --alarm-actions arn:aws:sns:us-east-1:123456789012:NotifyMe

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

AErrorAlarm

BErrorCount

CGreaterThanOrEqualToThreshold

DLessThanThreshold

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong metric name.

Using a comparison operator that triggers on low values.

The alarm is named ErrorAlarm, monitors the metric ErrorCount, and triggers when the sum is greater than or equal to the threshold.

Practice

1. What is the primary purpose of a CloudWatch Logs log group?

easy

A. To act as a container for multiple log streams

B. To store individual log events directly

C. To trigger alarms based on log data

D. To archive logs permanently

Solution

1. Step 1: Understand log group role

   A log group is a container that holds multiple log streams, organizing logs by application or resource.

2. Step 2: Differentiate log streams and groups

   Log streams are individual sequences of log events within a log group, not the group itself.

3. Final Answer:

   To act as a container for multiple log streams -> Option A

4. Quick Check:

   Log group = container for streams [OK]

Hint: Log groups hold streams; streams hold logs [OK]

Common Mistakes:

• Confusing log groups with log streams
• Thinking logs are stored directly in groups
• Assuming groups trigger alarms directly

2. Which of the following is the correct AWS CLI command to create a new CloudWatch Logs log group named MyAppLogs?

easy

A. aws cloudwatch create-log-group --name MyAppLogs

B. aws logs create-log-group --log-group-name MyAppLogs

C. aws logs new-log-group --group-name MyAppLogs

D. aws logs add-log-group --name MyAppLogs

Solution

1. Step 1: Identify correct AWS CLI service and command

   The correct service is 'logs' and the command to create a log group is 'create-log-group'.

2. Step 2: Check command syntax

   The parameter for the log group name is '--log-group-name', matching aws logs create-log-group --log-group-name MyAppLogs exactly.

3. Final Answer:

   aws logs create-log-group --log-group-name MyAppLogs -> Option B

4. Quick Check:

   Correct CLI syntax = aws logs create-log-group --log-group-name MyAppLogs [OK]

Hint: Use 'aws logs create-log-group' with --log-group-name [OK]

Common Mistakes:

• Using wrong service name like 'cloudwatch' instead of 'logs'
• Incorrect command verbs like 'new-log-group'
• Wrong parameter names like '--name'

3. Given the following AWS CLI command, what will be the retention period set for the log group AppLogs?

aws logs put-retention-policy --log-group-name AppLogs --retention-in-days 14

medium

A. Logs will be kept for 7 days

B. Logs will be kept indefinitely

C. Logs will be kept for 14 days

D. Logs will be deleted immediately

Solution

1. Step 1: Understand the put-retention-policy command

   This command sets how many days logs are retained before deletion.

2. Step 2: Interpret the retention-in-days value

   The parameter '--retention-in-days 14' means logs are kept for 14 days.

3. Final Answer:

   Logs will be kept for 14 days -> Option C

4. Quick Check:

   Retention days = 14 [OK]

Hint: Retention days = value in --retention-in-days [OK]

Common Mistakes:

• Assuming default retention instead of set value
• Confusing retention period with log group creation
• Thinking logs are kept indefinitely by default

4. You run this command but get an error:

aws logs put-retention-policy --log-group-name NonExistentGroup --retention-in-days 30

What is the most likely cause?

medium

A. The log group 'NonExistentGroup' does not exist

B. Retention period 30 days is not allowed

C. You must specify a log stream name instead

D. The AWS CLI command is misspelled

Solution

1. Step 1: Check existence of log group

   The command requires the log group to exist before setting retention.

2. Step 2: Validate retention period and command syntax

   Retention of 30 days is valid and the command syntax is correct.

3. Final Answer:

   The log group 'NonExistentGroup' does not exist -> Option A

4. Quick Check:

   Retention needs existing log group [OK]

Hint: Retention policy requires existing log group [OK]

Common Mistakes:

• Assuming retention period is invalid
• Confusing log stream with log group
• Thinking command syntax is wrong

5. You want to organize logs from multiple microservices in CloudWatch Logs. Which approach best follows AWS best practices?

hard

A. Store all logs in a single log stream for simplicity

B. Create one log stream for all microservices in a single log group

C. Create one log group per instance and one log stream per microservice

D. Create one log group per microservice and multiple log streams per instance

Solution

1. Step 1: Understand log group and stream organization

   Best practice is to use log groups to separate different applications or microservices.

2. Step 2: Assign log streams per instance or source

   Within each log group, use multiple log streams to separate logs by instance or container.

3. Step 3: Evaluate options

   Create one log group per microservice and multiple log streams per instance matches best practice: one log group per microservice, multiple streams per instance.

4. Final Answer:

   Create one log group per microservice and multiple log streams per instance -> Option D

5. Quick Check:

   Group per microservice, streams per instance [OK]

Hint: Group by microservice, stream by instance [OK]

Common Mistakes:

• Mixing microservices in one log group
• Using one stream for all logs causing confusion
• Creating groups per instance instead of per service