AWS Cloud Developer: Messaging and Containers Flashcards
Differences between Notifications and Messages
Notifications are sent to Humans
Messaging occurs between internet-based devices and appliccations
SNS -simple notification service
Amazon Simple Notification Service (or SNS) is a cloud service that allows you to send notifications to the users of your applications. SNS allows you to decouple the notification logic from being embedded in your applications and allows notifications to be published to a large number of subscribers.
Features of SNS
SNS uses a publish/subscribe model.
SNS can publish messages to Amazon SQS queues, AWS Lambda functions, and HTTP/S webhooks.
Which model is used by SNS
Publish/subscribe model
Users need to subscribe in order to receive notifications
How are notifications sent to end users using SNS
Mobile push
text messages
email
How many messages can one notification contain?
one message
Can SnS be used to send messages to both people and applications?
Yes
Application-to-application messaging
Application-to-application messaging supports subscribers such as AWS Lambda functions, Amazon SQS queues, HTTP/S endpoints, and AWS Event Fork Pipelines. For more information, see Using Amazon SNS for application-to-application (A2A) messaging.
Application-to-person notifications
Application-to-person notifications provides user notifications to subscribers such as mobile applications, mobile phone numbers, and email addresses. For more information, see Using Amazon SNS for application-to-person (A2P) messaging.
Queues
A queue is a data structure that holds requests called messages. Messages in a queue are commonly processed in order, first in, first out (or FIFO).
Messaging queues improve:
performance
scalability
user experience
What type of processing does queuing support?
asynchronous processing
SQS -Simple Queue Service
Amazon Simple Queue Service (SQS) is a fully managed message queuing service that allows you to integrate queuing functionality in your application. SQS offers two types of message queues: standard and FIFO.
Features of SQS
send messages
store messages
receive messages
How many messages can FIFO queues support?
FIFO queues support up to 300 messages per second.
2 types of message queues
Standard and FIFO
When to use a FIFO queue?
When ordering is important
Main difference between FIFO and Standard queues?
FIFO queues guarantee the ordering of messages.
FIFO messages are processed exactly once
Standard queues offer best-effort ordering but no guarantees.
Standard queues deliver a message at least once, but occasionally more than one copy of a message is delivered.
A container
A container consists of everything an application needs to run: the application itself and its dependencies (e.g. libraries, utilities, configuration files), all bundled into one package.
Each container is an independent component that can run on its own and be moved from environment to environment.
Docker
A Docker container image is a lightweight, standalone, executable package of software that includes everything needed to run an application: code, runtime, system tools, system libraries and settings.
Difference between Containers and Virtual Machines
Containers and virtual machines have similar resource isolation and allocation benefits, but function differently because containers virtualize the operating system instead of hardware. Containers are more portable and efficient.
ECS Elastic Container Service
ECS is an orchestration service used for automating deployment, scaling, and managing of your containerized applications. ECS works well with Docker containers by:
launching and stopping Docker containers
scaling your applications
querying the state of your applications
Which is the only container platform supported by Amazon ECS?
Docker
Kubernetes
An orchestration service for docker containers
