2 Amazon EC2 Instances and Scaling Free Online FlashCards

What does an EC2 instance type define?

An instance type defines an instance’s virtual hardware, including its CPU, memory, storage, and networking capacity.

What does an Amazon Machine Image provide?

An Amazon Machine Image (AMI) is a bootable template that specifies the operating system and software, and includes block-device mapping for attached storage.

What is a key property of Amazon EBS storage?

Amazon EBS provides persistent block storage that can be attached to an instance and managed separately; volumes can also be backed up with snapshots.

How can an instance keep a persistent public IPv4 address?

An automatically assigned public IP may change after a stop and start. Use an Elastic IP when a persistent public IPv4 address is needed.

How do EC2 security groups control network traffic?

A security group is a stateful virtual firewall. Its inbound rules permit specified protocols, ports, and sources; outbound rules govern traffic leaving the instance.

How does stopping an EC2 instance differ from terminating it?

Stopping an EBS-backed instance is reversible; terminating it is permanent. Stopping does not remove charges for resources that remain, such as EBS volumes.

What capacity settings define an EC2 Auto Scaling group?

An EC2 Auto Scaling group uses minimum, desired, and maximum capacity settings. It maintains desired capacity and can replace unhealthy instances.

How often does basic EC2 monitoring send metrics to CloudWatch by default?

Basic EC2 metrics, including CPU and network measurements, are sent to CloudWatch every five minutes by default. Detailed monitoring provides one-minute intervals.

What workload characteristic is important when using Spot Instances?

Spot Instances use spare capacity and can be interrupted, so they suit only workloads that can tolerate interruption.

Which instance family suits processor-intensive workloads?

Compute-optimized types suit processor-intensive work, such as batch processing.

How should permissions be granted to applications running on an EC2 instance?

An IAM instance profile lets applications on an instance access AWS services. Grant only the permissions those applications require.

What happens to instance-store data when an instance stops?

Instance-store data is temporary and does not survive stopping, hibernating, or terminating the instance. Use it for disposable data, not the only copy of valuable data.