EC2 Flashcards
What is EC2?
A web service that provides compute capacity on the cloud
What prompts the creation of an ephemeral port?
“When an SSH request is made
The OS generates a random port which is assigned as the source port for return traffic”
What is an instance store?
“provides temporary block-level storage for your instance.
Good for temp info that changes frequently like buffers caches scratch data”
When is the data in an instance store lost?
“The underlying disk drive fails
the instance stops
the instance terminates”
What is a spot instance?
An instance that is available for less than the On-demand price becasue of it not being used
What is instance warm-up?
When a target tracking scaling policy notifies an instance that it will be required an the EC2 spins up before it is needed reducing latency
What is a placement group?
“designated strategic groupings of instances in AWS coming in 3 styles
Cluster - packs of instances close together in an AZ for low latency HPC applications
Partition - spreads your instance across logical partitions such that groups of instances in one partition do not hardware used in large distributed and replicated workloads like Hadoop Cassandra and Kafka
Spread - stricktly places a mall group or instances across distinct underlying hardware to reduce correlated failures”
How can you merge placement groups?
instances can be migrated from one froup to another but merging placement groups is not supported
What is an ENA?
“Elastic Network Adapter
a custom network interface for EC2s for high throughput, packat per second(PPS) performance and low latencies
For use on EC2s with supporting Linux kernal and distrobution”
“(not sure about this one)
How do you set up an ENA?”
“check to see if your instance type supports the featureby running
ethtool -i etho
get the ena as the driver”
what is a spot instance?
Instances at up to 90% reduced prices but they can be terminated if reserved by other AWS users
What is an RI?
“Reserved instance
commit to a specific EC2 usage contract to recieve services at a lower cost”
