You currently have a set of EC2 Instances in a private subnet that communicates to the internet via a NAT instance.
You now plan to start using a NAT gateway and replace the usage of the NAT Instance.
During the transition , which of the following needs to be noted.
Click on the arrows to vote for the correct answer
A. B. C. D.Answer - C.
The AWS documentation mentions the following.
If you change your routing from a NAT instance to a NAT gateway, or if you disassociate the Elastic IP address from your NAT instance, any current connections are dropped and have to be re-established.
Ensure that you do not have any critical tasks (or any other tasks that operate through the NAT instance) running.
For more information on NAT gateways, please visit the below link:
http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/vpc-nat-gateway.htmlWhen transitioning from a NAT instance to a NAT gateway in AWS, there are a few things that need to be noted to ensure a smooth transition.
A NAT instance is an EC2 instance configured to forward traffic from instances in a private subnet to the internet via the internet gateway. In contrast, a NAT gateway is a managed service provided by AWS that allows outbound internet traffic from instances in a private subnet.
Option A is not accurate because when transitioning to a NAT gateway, it is essential to note that the existing connections will not be automatically moved from the NAT instance to the NAT gateway. It is because the NAT instance and NAT gateway are distinct and separate services, and they use different IP addresses.
Option B is the correct answer. During the transition, existing connections to the NAT instance will go through a connection draining period. Connection draining is the process of allowing existing connections to complete their transactions before terminating the NAT instance. During this period, there will be no disruptions to the existing service, and it provides a smooth transition from the NAT instance to the NAT gateway.
Option C is not accurate because the disruption during the transition period will be minimal. However, it is still recommended to plan and schedule the transition during a maintenance window to avoid any unexpected issues.
Option D is not accurate because it is possible to replace a NAT gateway with a NAT instance. However, it is essential to note that the NAT gateway is a managed service provided by AWS, and it is designed to offer higher scalability, availability, and performance compared to a NAT instance.
In summary, when transitioning from a NAT instance to a NAT gateway, it is essential to plan and schedule the transition during a maintenance window, take advantage of connection draining to avoid any disruptions, and note that existing connections will not be automatically moved to the NAT gateway.