Applications Flashcards
What is CloudFormation?
A way of scripting your cloud environment. You can use quick start to use a bunch of cloudformation templates built by AWS solutions architects allowing you to create complex environments quickly
What is ElasticBeanstalk?
Automatically completes capacity provisioning, load balancing and scaling just add code!
What SQS?
Simple Queuing Service (pull based)
Why use SQS?
Allows you to decouple your infrastructure if allows messages to be sent and kept in a queue.
How long can messages in SQS be kept in a queue?
1 min to 14 days
What are the types of SQS?
1) Standard
2) FIFO
Is order guaranteed in Standard SQS?
No, order is not guaranteed and there can be duplications
Is order guaranteed in FIFO SQS?
Yes, order is strictly maintained and messages are delivered once and only once
What is visibility time out in SQS?
Visibility time out is the time that the messages in the SQS are invisible in the queue after a reader picks up that message
What happens in SQS when the job is processed before the visibility timeout expires?
The message will be deleted from the queue
What happens in SQS when a job is NOT process within the visibility timeout period?
The message will become visible in the queue again and another reader will process it
What is the maximum visibility time out in SQS?
12 hours
Does SQS guarantee that your message will be processed once?
Yes
What is SQS long polling?
A way to retrieve messages from your SQS queues. Long polling doesn’t return a response until a message arrives in the queue or the long poll times out
Why use SQS long polling?
It is cheaper
How does SQS short polling work?
Short polling returns a response immediately even if the message is empty
What is SWF service?
Simple Workflow Service –> a way of managing workflows in the cloud
What are the 3 actors in SWF service?
1) Workflow starters –> e.g. an app that can start initiate a workflow
2) Deciders –> Controllers of the flow of activity tasks in a workflow. e.g. is something has finished or has failed in a workflow then the decider decides what to do next
3) Activity workers –> Carry out activity tasks
What is the retention period of tasks in SWF service?
up to 1 year
What is the key difference between SQS and SWF?
SWF is a task oriented API where as SQS is message orientated
Will SWF duplicate tasks?
No tasks are never duplicated and tasks are only ever processed once
What is the main benefit of using SWF over SQS?
SWF tracks all tasks and events whereas SQS requires you to implement your own application level tracking especially if your application uses multi queues
What is SNS?
Simple Notification Service (push based) it allows messaging capabilities for apps within AWS env. e.g. email, sms, etc…
What are the benefits of using SNS?
1) Simple APIs and easy to integrate
2) inexpensive
3) Flexible message delivery methods
What is the difference between SNS and SQS?
Both messaging, but SQS = pull (poll) SNS = push
What is an Elastic transcoder?
Service that allows conversion of file formats e.g. media on tablets, mobile, mobiles e.t.c.
What is API gateway?
AP gateway is a way to access your AWS infratructure
Does API gateway have caching capability?
Yes, to improve performance
What are the benefits of using API gateway?
1) Low cost and scales automatically
2) Can throttle API gateway to prevent attacks
3) Can log access to cloud watch
What must you have enabled if you are using JS or AJAX that use multiple domains?
CORS –> Cross origin resource sharing. Must be enforced by clients browser
What is Kinesis?
Kinesis is a mehod of capturing and analyzing data in real time
What are the 3 types of kinesis?
1) Streams –> persists data for 24 hours. Sores in streams
2) Firehose –> analysis of data in real time. Uses lambda and stored in S3
3) Analytics –> Helps with analysis in both streams and firehose
What is Cognito?
Allows users to authenticate users using a web identify provider e.g. Facebook, google or Amazon
What are the 3 steps in Cognito authentication?
1) User authenticates with web identity provider
2) Cognito receives authentication token}
3) Token exchanged for temporary access to AWS credentials allowing them to access to assume an IAM role
what is a user pool in Cognito?
User based. Used for user registration authentication, registration and account recover
What is a identity pool in Cognito?
Authorizes access to your AWS resources
