How long can sqs messages be kept in the queue? What is the default retention period?
1minute to 14 days. Default being 4days
What is meant by visibility timeout? What is its default value
The time that the message is invisible in sqs after a reader picks up that message.
If the message is processsed, then the message gets deleted.
if not then the message becomes visible in the queue again. Another reader processes it. This could result in the same messgae being delivered twice
Default = 30 secs. Should be increased it the task takes longer obvsly
What are the different types of queues in sqs and what are the differences
Standard queues: Best effort ordering. Messages delivered at least once
FIFO queues : order striclty preserved. Mssage delivered once with no ducplicates so good for banking apps.
What is SQS? What is its guarantee? Why do we use it?
- (The oldest service of AWS)
- - Gives you access to this message queue that can be used to store messages while waiting for a computer to process them.
- Its this neat lil distributed queue system that allows web services to reliably queue messages that one component in the app makes, ready to be eaten by another.
-basically a queue for messages that need processing.
Messages will be delivered once
Why do we use it?
Allows you to decouple the components of an app so they are independent.
Difference between SES and SNS
SES is email only. Can be used for icoming and outgoing email. Not subscription based
SNS is SMS, HTTP, SQS, email and push notifs only. Its a subscription model
Is SQS a push or pull based system?
Its a pull based system.
What is the problem with launching RDS from inside the EBS? WHat is the benefit and when would you ever really want to launch an ebs instance from within the ebs?
If you terminate your EBS instance, the database will also be terminated.
- Quick and easy to add to database.
- Good for test and dev environments
What even is elastic beanstalk?
- - Service for deploying and scaling web apps developed in many popular languages like java python, ruby, docker.
- - Its gr8 cos you can focus on writing code and not worry about the infrastructure stuff. You can just throw it code in a zip file and it will configure the env for you.
- - It will manage your ec2 instances for you or you can take full administrative control if ya want
How do you launch RDS from outside elastic beanstalk?
Decouple RDS from your EBS environment and just launch the RDS from the RDS section of the console.
- 1. An additional security group must be added to your environments autoscaling security group
- 2. Provide connection string configuration information to your application servers. (endpoint, password)
What are the 4 different deployment approaches with elastic beanstalk and how do they differ?
- all at once -> gives downtime
- Rolling, reduced capacity
- Rolling with additional batch -> no downtime
- Immutable -> maintains full capacity
How do you configure elastic beanstalk?
- need to use elastic beanstalk config files
- pls finish
WHat is streaming data. give examples
- Data generated continuously by thousands of datasources
- Purchases from online sotres
- stock prices
- game data etc
What is kinesis and what are the main three services
- Platform to send streaming data. Kinesis helps to load and analyze streaming data and prvide ability to build custom apps for business needs
- Kinesis streams
- Kineses firehose
- kinesis analytics
What is kinesis streams and whats inside one
Stores data from ec2, phones, computers.
Data is stored in shards. Can be retained for 7 days. normally 24hrs.
what is kinesis firehose
no shards, no streams. Completely automated. Can use lamda if want. Data is sent into s3. Theres no data retention default since it ends up in s3 anyhow.
What is kinesis anlytics
Allows you to run sql queries. lets you analyse data in kinesis. Kinesis streams and kinesis firehose.