Technology Flashcards
What is Amazon EC2?
Elastic Cloud Compute.
This is the most popular part of AWS offering - run computing on EC2, store data on EBS, use ELB to distribute workload, scale with ASG. (
What can you choose / customise with an EC2 instance?
> OS: Linux/Windows > CPU > RAM > Storage (either EBS/EFS, or EC2 Instance Store) > Network card > Firewall & bootstrap
What are the different instance types available?
> general purpose: balance of compute, memory, and networking resources
compute optimized: ideal for compute-bound applications, such as gaming servers
memory optimized: fast performance, workloads process large datasets in memory
accelerated computing: use hardware accelerators (coprocessors) to perform some functions more efficiently
storage optimized: for high, sequential read and write access to large datasets on local storage
What are the different pricing options with EC2 instances?
> On demand > Saving Plans (1-year / 3-year) > Reserved Instances > Spot Instances > Dedicated hosts
What AWS service manages the adding / removing of instances in response to changing demand?
Amazon EC2 Auto Scaling
What methods can be used in EC2 Auto Scaling?
> Dynamic scaling: responds to changing demand.
> Predictive scaling: automatically schedules the right number of Amazon EC2 instances based on predicted demand.
What do you have to set with Amazon EC2 Auto Scaling?
> Min number of EC2 instances
Max number of EC2 instances
Desired number
What AWS Service directs incoming traffic between your EC2 instances?
Elastic Load Balancing (ELB)
What does ELB do?
Directs incoming traffic between your EC2 instances. It ensures:
> Decoupled architecture between your public facing resources, and private resources
> Workload is balanced between instances in use
What is Amazon Simple Notification Service (SNS)?
A pub/sub service - push notifications to users. E.g., send an email to an email list, or elicit an action of AWS Lambda functions.
What is Amazon Simple Queue Service (SQS)?
A message queuing service, to communicate between components/services in AWS.
What is Amazon Virtual Private Cloud?
It is a service to contain your resources in a logically isolated virtual network.
How do you allow access into your resources (VPC)?
Using an Internet Gateway
What service/product can you use to establish a private dedicated connection to your VPC?
AWS Direct Connect.
What do subnets do?
They group and separate different resources in the cloud.
What is a Network Access Control List (Network ACL)?
“Passport control” - subnet boundaries.
Define what traffic can enter and exit a subnet.
What is a Security Group?
“Doorman” - Instance boundaries
Defines what traffic can enter/exit an instance. By default, allows none in, and all out.
True / False: A Network ACL is Stateful.
False. A network ACL is Stateless. A Security Group is Stateful.
What is Amazon Route 53?
AWS’s Domain Name Service.
I.e., it translates website URLs into IP Addresses.
For an On Demand EC2 instance, what unit of time are you billed by?
> For a Linux instance, by the second (after the first minute)
For any other OS, by the hour
What type of Reserved Instances are there?
1) Convertible: You can change the instance type
2) Scheduled: Launch within the time window you reserve
Under the Shared Responsibility Model, who is responsible for operating-system patches and updates on EC2 Instances?
You (the customer).
The customer is responsible for operating-system patches and updates on EC2 Instances, as well as data security on the instances, Security Groups rules, etc.
What is an Instance Store?
Temporary memory attached to an EC2 instance. It is deleted between an Instance terminating and restarting.
What is an EBS Volume?
Elastic Block Store: A network drive you can attach to a specific instance for persistent storage.
What is a good (general) use case for EBS?
When you want to make block changes to a file / data object. E.g., change certain parts of a single 8GB video, using EBS, you can just change parts in isolation, rather than having to reupload all of the file.
What is an AMI?
Amazon Machine Image
They are a customization of an EC2 instance. You can use Public Amazon ones, or build your own.