05-EC2 Basics Flashcards
What is EC2?
It provides virtual machines known as “instances” that can be deployed with multiple Operating Systems, runtime environments, databases, and applications.
What resilience level is EC2?
AZ resilient as EC2 instances are deployed to a single subnet in a single AZ.
What options are available when deploying an EC2 instance?
Various instance sizes, various operating systems, additional storage, GPUs, advanced networking, or special processors.
What does AWS handle vs. what the end user handles for EC2?
AWS handles the hardware, storage, and underlying virtual infrastructure. Users handle the Guest OS, instance configuration, monitoring and managing the instance.
How does EC2 incur charges?
CPU and memory usage (instance resources - only when it is running). Storage usage (EBS or local storage - charges whether running or not). Network activity. Commercial software that may be launched with the instance.
What are the two most common types of storage used by EC2?
Local host storage, EBS storage
What are the primary states of an EC2 instance?
Running: Active and consuming resources. Stopped: Powered off, but can be started against. Terminated: Instance has been permanently deleted.
What are you charged for when an instanced is in a stopped state?
Storage costs.
What is an Amazon Machine Image (AMI)?
Is an image of an EC2 instance and can be used to create new instances or can be created from an existing instance. Basically, it is a server image or installation disks for OS, such as Windows, Mac OS, or Linux.
What does an AMI contain?
Permissions: Determine who can launch instances from the AMI. Boot Volume: Contains the OS and any additional volumes. Block Device Mapping: Links the volumes presented to the operating system, identifying which volumes serves as the boot volume and what as data volumes.
What permissions are available to an AMI?
Accessible to the owner. Can be made publicly accessible so that anyone can use it. Can be made access to specific AWS accounts.
What is an SSH Key pair?
Used to authenticate to an EC2 instance and consists of two components. A private key and a public key. AWS keeps the public key and applies it to the instance whereas you download the private key (and store it in a safe location) so that you can use it to SSH to a Linux instance or used to decrypted a password for a Windows instance.
