Instance states (running, stopped, terminated) in AWS - Step-by-Step Execution

Process Flow - Instance states (running, stopped, terminated)

Launch Instance

↓

State: running

↓

Stop Instance

↓

State: stopped

↓

Start Instance

↓

State: running

↓

Terminate Instance

↓

State: terminated

↓

No further actions allowed

This flow shows how an AWS instance moves through states: launched (running), stopped, started (running), and finally terminated where it cannot be restarted.

Execution Sample

AWS

Launch instance -> Stop instance -> Start instance -> Terminate instance

This sequence shows an instance changing states from running to stopped to running, and then terminated.

Process Table

Step	Action	Instance State Before	Instance State After	Notes
1	Launch instance	N/A	running	Instance is launched and running
2	Stop instance	running	stopped	Instance is stopped but can be started again
3	Start instance	stopped	running	Instance is now running and usable
4	Terminate instance	running	terminated	Instance is permanently deleted
5	Start instance	terminated	terminated	Cannot start a terminated instance

💡 Instance reaches terminated state; no further actions allowed

Status Tracker

Instance State	Start	After Step 1	After Step 2	After Step 3	After Step 4	After Step 5
state	N/A	running	stopped	running	terminated	terminated

Key Moments - 2 Insights

Why can't we start the instance after it is terminated?

Because termination deletes the instance permanently, as shown in step 5 of the execution_table where the state remains terminated despite the start action.

Is the instance usable when it is stopped?

No, when stopped (step 2), the instance is not running and cannot serve requests, but it can be started again.

Visual Quiz - 3 Questions

Look at the execution_table, what is the instance state after step 2?

A running

B stopped

C terminated

D pending

💡 Hint

Check the 'Instance State After' column for step 2 in the execution_table

At which step does the instance become permanently unusable?

A Step 4

B Step 3

C Step 2

D Step 1

💡 Hint

Look for when the state changes to 'terminated' in the execution_table

If we try to start the instance after termination, what happens to the state?

A Changes to running

B Changes to stopped

C Remains terminated

D Changes to pending

💡 Hint

See step 5 in the execution_table where start action is attempted on terminated instance

Concept Snapshot

AWS Instance States:
- stopped: instance exists but not running
- running: instance is active and usable
- terminated: instance is deleted permanently
You can start a stopped instance to run it.
You cannot start a terminated instance.

Full Transcript

This visual execution shows how an AWS instance changes states. When launched, it starts in running state, where it can serve requests. Stopping it moves it to stopped, pausing usage but allowing restart. Starting it returns it to running. Terminating deletes it permanently, preventing any further start. The execution table tracks each step and state change, clarifying when actions are allowed or blocked.

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