Instance states (running, stopped, terminated) in AWS - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ service_behavior

intermediate

What is the state of an AWS EC2 instance immediately after you stop it?

You have an AWS EC2 instance running. You issue a stop command to it. What will be the instance state right after the stop command completes successfully?

A terminated

B pending

C shutting-down

D stopped

💡 Hint

Think about what 'stop' means compared to 'terminate'.

When you stop an EC2 instance, it transitions to the 'stopped' state, meaning it is powered off but still exists and can be started again.

🧠 Conceptual

intermediate

Which instance state means the instance is permanently deleted and cannot be restarted?

AWS EC2 instances have several states. Which state indicates the instance is permanently deleted and cannot be restarted or recovered?

A terminated

B stopped

C running

D pending

💡 Hint

Consider which state means the instance no longer exists.

The 'terminated' state means the instance is deleted and cannot be restarted. It is removed from your account.

❓ Architecture

advanced

What happens to the instance's EBS root volume when an instance is terminated?

You terminate an EC2 instance that uses an EBS root volume. What is the default behavior of the root EBS volume after termination?

A The root EBS volume is detached but retained

B The root EBS volume remains attached and running

C The root EBS volume is deleted automatically

D The root EBS volume is converted to an S3 bucket

💡 Hint

Think about default cleanup behavior for root volumes on termination.

By default, the root EBS volume is deleted when the instance is terminated unless the 'DeleteOnTermination' flag is set to false.

❓ security

advanced

Which instance state prevents you from connecting via SSH but still allows you to modify instance attributes?

An EC2 instance is in a state where you cannot connect to it via SSH, but you can still change its instance type or security groups. Which state is this?

A stopped

B running

C terminated

D shutting-down

💡 Hint

Think about when the instance is powered off but still exists.

When an instance is stopped, it is powered off so you cannot connect via SSH, but you can modify its attributes like instance type or security groups.

✅ Best Practice

expert

You want to ensure your EC2 instance data persists after stopping and starting the instance. Which storage and instance state combination guarantees this?

Select the combination of instance state and storage type that ensures your data remains intact after stopping and starting an EC2 instance.

A Instance terminated with EBS root volume

B Instance stopped with EBS root volume

C Instance stopped with instance store root volume

D Instance running with instance store root volume

💡 Hint

Instance store volumes lose data when stopped or terminated.

EBS volumes persist independently of instance state, so stopping and starting an instance with an EBS root volume keeps data intact. Instance store volumes lose data when the instance stops.

Practice

1. Which AWS EC2 instance state means the instance is currently powered on and ready to use?

easy

A. Running

B. Stopped

C. Terminated

D. Pending

Solution

1. Step 1: Understand EC2 instance states

   Instances can be in states like running, stopped, or terminated, indicating their power and availability status.

2. Step 2: Identify the state meaning 'powered on'

   The 'running' state means the instance is powered on and ready to use.

3. Final Answer:

   Running -> Option A

4. Quick Check:

   Running = Powered On [OK]

Hint: Running means instance is on and usable [OK]

Common Mistakes:

• Confusing stopped with running
• Thinking terminated means running
• Mixing pending with running

2. Which AWS CLI command correctly stops a running EC2 instance with ID i-1234567890abcdef0?

easy

A. aws ec2 terminate-instances --instance-ids i-1234567890abcdef0

B. aws ec2 reboot-instances --instance-ids i-1234567890abcdef0

C. aws ec2 start-instances --instance-ids i-1234567890abcdef0

D. aws ec2 stop-instances --instance-ids i-1234567890abcdef0

Solution

1. Step 1: Identify command to stop instance

   The command to stop an instance is stop-instances.

2. Step 2: Match instance ID usage

   The command must include --instance-ids i-1234567890abcdef0 to specify the instance.

3. Final Answer:

   aws ec2 stop-instances --instance-ids i-1234567890abcdef0 -> Option D

4. Quick Check:

   Stop instance = stop-instances command [OK]

Hint: Stop instance uses 'stop-instances' command [OK]

Common Mistakes:

• Using terminate instead of stop
• Using start instead of stop
• Using reboot instead of stop

3. What will be the state of an EC2 instance immediately after running this AWS CLI command?

aws ec2 terminate-instances --instance-ids i-0abcdef1234567890

medium

A. Running

B. Stopped

C. Terminated

D. Pending

Solution

1. Step 1: Understand the terminate-instances command

   This command deletes the instance permanently, changing its state to terminated.

2. Step 2: Identify the resulting state

   After termination, the instance cannot be started again and is marked as terminated.

3. Final Answer:

   Terminated -> Option C

4. Quick Check:

   Terminate command = Terminated state [OK]

Hint: Terminate means instance is deleted permanently [OK]

Common Mistakes:

• Thinking terminated means stopped
• Confusing terminate with stop
• Expecting instance to restart automatically

4. You tried to start an EC2 instance but got an error saying the instance does not exist. What is the most likely cause?

medium

A. The instance is terminated

B. The instance is in running state

C. The instance is in stopped state

D. The instance is pending

Solution

1. Step 1: Analyze error meaning

   If AWS says the instance does not exist, it usually means it was deleted or terminated.

2. Step 2: Match instance state to error

   Terminated instances are removed and cannot be started again, causing this error.

3. Final Answer:

   The instance is terminated -> Option A

4. Quick Check:

   Instance not found = Terminated state [OK]

Hint: Instance not found means terminated, not stopped [OK]

Common Mistakes:

• Assuming stopped means instance missing
• Confusing running with missing
• Ignoring termination possibility

5. You want to save costs by stopping an EC2 instance but keep its data intact for later use. Which instance state should you use and why?

hard

A. Terminate, because it deletes the instance and saves all costs

B. Stop, because it powers off the instance but keeps data on the disk

C. Running, because it keeps the instance active and data safe

D. Pending, because it prepares the instance for shutdown

Solution

1. Step 1: Understand cost and data retention

   Stopping an instance powers it off but keeps the attached storage intact, preserving data.

2. Step 2: Compare with termination

   Terminating deletes the instance and storage, losing data and cannot be restarted.

3. Step 3: Choose correct state for saving costs and keeping data

   Stopping is the correct choice to save costs while keeping data safe.

4. Final Answer:

   Stop, because it powers off the instance but keeps data on the disk -> Option B

5. Quick Check:

   Stop = Save cost + keep data [OK]

Hint: Stop to save cost and keep data intact [OK]

Common Mistakes:

• Choosing terminate and losing data
• Thinking running saves cost
• Confusing pending with stop