Scheduled scaling in AWS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to specify the scheduled action name.

AWS

ScheduledActionName: "[1]"

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

ADesiredCapacity

BInstanceType

CAutoScalingGroupName

DScaleUpMorning

Attempts:

3 left

💡 Hint

Common Mistakes

Using resource property names instead of a descriptive name.

Leaving the name blank.

The scheduled action name uniquely identifies the scaling schedule.

2fill in blank

medium

Complete the code to set the desired capacity for the scheduled scaling.

AWS

DesiredCapacity: [1]

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

A"High"

BInstanceCount

C5

D"Auto"

Attempts:

3 left

💡 Hint

Common Mistakes

Using strings instead of numbers.

Using undefined variables.

DesiredCapacity must be a number indicating the number of instances to run.

3fill in blank

hard

Fix the error in the cron expression for the scheduled scaling.

AWS

Schedule: "cron([1])"

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

A0 8 * * ? *

B8 0 * * ? *

C0 8 * * *

D0 8 ? * *

Attempts:

3 left

💡 Hint

Common Mistakes

Using five-field cron expressions instead of six.

Misplacing the '?' character.

The correct AWS cron expression for 8 AM daily is '0 8 * * ? *'.

4fill in blank

hard

Fill both blanks to define the Auto Scaling group and the start time for the scheduled action.

AWS

AutoScalingGroupName: "[1]",
StartTime: "[2]"

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

AMyAutoScalingGroup

B2024-07-01T08:00:00Z

C2024-07-01 08:00:00

DScalingGroup1

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect date formats.

Using wrong Auto Scaling group names.

The AutoScalingGroupName must match the group you want to scale. StartTime must be in ISO 8601 format with 'Z' for UTC.

5fill in blank

hard

Fill all three blanks to create a scheduled scaling action with name, desired capacity, and recurrence.

AWS

ScheduledActionName: "[1]",
DesiredCapacity: [2],
Schedule: "cron([3])"

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

AEveningScaleDown

B2

C0 20 * * ? *

DMorningScaleUp

Attempts:

3 left

💡 Hint

Common Mistakes

Using invalid cron expressions.

Using string values for DesiredCapacity.

Use a descriptive name for the scheduled action, a numeric desired capacity, and a valid AWS cron expression for 8 PM daily.

Practice

1. What is the main purpose of scheduled scaling in AWS?

easy

A. To automatically adjust resources at specific times

B. To manually increase server capacity when needed

C. To monitor security threats in real-time

D. To backup data at scheduled intervals

Solution

1. Step 1: Understand scheduled scaling concept

   Scheduled scaling is designed to change resource capacity automatically based on a set schedule.

2. Step 2: Compare options with the concept

   Only To automatically adjust resources at specific times describes automatic adjustment at specific times, matching scheduled scaling.

3. Final Answer:

   To automatically adjust resources at specific times -> Option A

4. Quick Check:

   Scheduled scaling = automatic timed resource adjustment [OK]

Hint: Scheduled scaling means automatic resource changes on a timer [OK]

Common Mistakes:

• Confusing scheduled scaling with manual scaling
• Thinking it handles security or backups
• Assuming it reacts only to traffic, not time

2. Which of the following is a valid cron expression for scheduled scaling in AWS?

easy

A. cron(0 0 0 0 ? *)

B. cron(60 24 * * ? *)

C. cron(* * * * *)

D. cron(0 12 * * ? *)

Solution

1. Step 1: Review cron expression format in AWS

   AWS cron expressions have six fields: minutes, hours, day-of-month, month, day-of-week, year.

2. Step 2: Validate each option

   cron(0 12 * * ? *) is valid: minute=0, hour=12, day-of-month=*, month=*, day-of-week=?, year=*. cron(0 0 0 0 ? *) has invalid zero day-of-month and month values. cron(60 24 * * ? *) has invalid 60 minutes and 24 hours. cron(* * * * *) has only five fields, missing year.

3. Final Answer:

   cron(0 12 * * ? *) -> Option D

4. Quick Check:

   Valid AWS cron = 6 fields, correct ranges [OK]

Hint: AWS cron needs 6 fields with valid ranges [OK]

Common Mistakes:

• Using 5-field cron instead of 6-field
• Setting minutes or hours out of range
• Confusing day-of-week and day-of-month

3. Given this scheduled scaling configuration snippet:

{"ScheduledActionName": "ScaleUpMorning", "StartTime": "2024-07-01T08:00:00Z", "DesiredCapacity": 5}

What will happen at 8 AM UTC on July 1, 2024?

medium

A. The resource capacity will be set to 5

B. The resource capacity will decrease to 0

C. The scaling action will be ignored due to missing EndTime

D. The resource capacity will remain unchanged

Solution

1. Step 1: Understand the scheduled action parameters

   The action named "ScaleUpMorning" is set to start at 8 AM UTC on July 1, 2024, with DesiredCapacity 5.

2. Step 2: Interpret the effect of StartTime and DesiredCapacity

   At the StartTime, the capacity will be set to 5. EndTime is optional and does not block the action.

3. Final Answer:

   The resource capacity will be set to 5 -> Option A

4. Quick Check:

   StartTime triggers capacity change to DesiredCapacity [OK]

Hint: StartTime sets capacity; EndTime is optional [OK]

Common Mistakes:

• Thinking EndTime is required to trigger scaling
• Assuming capacity decreases without explicit setting
• Ignoring the StartTime effect

4. You created a scheduled scaling action with this cron expression:
cron(0 25 * * ? *)
Why does the scaling not trigger as expected?

medium

A. The day-of-week field is missing

B. The minute value 0 is invalid

C. The hour value 25 is invalid in cron expressions

D. The cron expression needs only 5 fields

Solution

1. Step 1: Check the hour field in the cron expression

   The hour field is set to 25, but valid hour values are 0 to 23.

2. Step 2: Understand cron validation rules in AWS

   AWS rejects cron expressions with invalid field values, so the scaling action won't trigger.

3. Final Answer:

   The hour value 25 is invalid in cron expressions -> Option C

4. Quick Check:

   Hour must be 0-23 in AWS cron [OK]

Hint: Check cron field ranges; hours max 23 [OK]

Common Mistakes:

• Assuming minute 0 is invalid
• Thinking day-of-week is mandatory
• Using 5 fields instead of 6

5. You want to reduce your AWS Auto Scaling group capacity to 2 instances every night at 11 PM UTC and increase it to 10 instances every weekday morning at 7 AM UTC. Which setup correctly uses scheduled scaling to achieve this?

hard

A. Create one scheduled action with cron(0 23,7 * * ? *) setting DesiredCapacity=2 and DesiredCapacity=10

B. Create two scheduled actions: one with cron(0 23 * * ? *) setting DesiredCapacity=2, another with cron(0 7 ? * MON-FRI *) setting DesiredCapacity=10

C. Create two scheduled actions: one with rate(1 day) setting DesiredCapacity=2, another with rate(1 hour) setting DesiredCapacity=10

D. Create one scheduled action with cron(0 7 * * ? *) setting DesiredCapacity=10 only

Solution

1. Step 1: Understand the scheduling requirements

   Capacity should be 2 at 11 PM daily and 10 at 7 AM on weekdays only.

2. Step 2: Match cron expressions to requirements

   cron(0 23 * * ? *) runs daily at 11 PM; cron(0 7 ? * MON-FRI *) runs at 7 AM Monday to Friday. Two separate scheduled actions are needed with correct DesiredCapacity values.

3. Final Answer:

   Create two scheduled actions: one with cron(0 23 * * ? *) setting DesiredCapacity=2, another with cron(0 7 ? * MON-FRI *) setting DesiredCapacity=10 -> Option B

4. Quick Check:

   Separate cron for each time and capacity [OK]

Hint: Use separate scheduled actions with correct cron and capacity [OK]

Common Mistakes:

• Trying to set two capacities in one scheduled action
• Using rate expressions instead of cron for weekdays
• Missing weekday restriction for morning scale-up