AWS Certified Advanced Networking - Specialty: Rebooting an EBS Backed EC2 Instance

Rebooting an EBS Backed EC2 Instance

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Question

A user has launched an EBS backed EC2 instance.

The user has rebooted the instance.

Which of the below mentioned statements is not true with respect to the reboot action?

Answers

Explanations

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A. B. C. D.

Answer - D.

When you reboot your instance, as per the AWS documentation the following actions occur.

An instance reboot is equivalent to an operating system reboot.

In most cases, it takes only a few minutes to reboot your instance.

When you reboot an instance, it remains on the same physical host, so your instance keeps its public DNS name (IPv4), private IPv4 address, IPv6 address (if applicable), and any data on its instance store volumes.

From the above explanation it is pretty straightforward to understand that Option D is the right option.

For more information on rebooting instance, please visit the link:

http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-reboot.html

When an Amazon Elastic Compute Cloud (Amazon EC2) instance is rebooted, it is stopped and then started again. This process can help to troubleshoot operating system issues, to apply software updates, or to reconfigure the instance.

In the context of the given question, the user has launched an EC2 instance backed by Amazon Elastic Block Store (Amazon EBS), which means that the instance's root volume is an EBS volume that is persisted independently of the instance.

With respect to the reboot action, the following statements are true:

A. The private and public address remains the same: When an instance is stopped and started again, it is assigned a new private IP address by default, but the same elastic network interface (ENI) is reattached to the instance. This means that the instance retains its private IP address and any associated Elastic IP address, if one is assigned.

B. The Elastic IP remains associated with the instance: If an Elastic IP address is associated with an instance and the instance is stopped and started again, the Elastic IP address remains associated with the instance. However, if the instance is terminated and then launched again, the Elastic IP address needs to be re-associated with the new instance.

C. The volume is preserved: When an EBS-backed instance is rebooted, the EBS volume that serves as the instance's root volume is preserved. This means that any data that was stored on the volume before the reboot is still available after the reboot.

D. The instance runs on a new host computer: When an EC2 instance is stopped and started again, it may run on the same physical host computer or on a different one. This is because EC2 instances are designed to be highly available and resilient, and Amazon EC2 uses a variety of mechanisms to distribute instances across multiple physical hosts for fault tolerance and scalability.

Therefore, the statement that is NOT true with respect to the reboot action is D: "The instance runs on a new host computer." This statement is potentially true, but it is not always true. When an instance is rebooted, it may continue to run on the same physical host computer or on a different one, depending on the current capacity and availability of the Amazon EC2 service.