AWS Essentials Flashcards
What three things does an AWS account provide? Aside from those, what incidental protection does an account give an account holder?
A way to authenticate, authorize, and bill. An account automatically limits the blast radius for resources within a specific account.
What is a principal?
An entity which can log into an AWS account.
What does a principal need to do to interact with a system?
Authenticate.
What mechanism does AWS use to authenticate and authorize principals?
IAM
If a system has mitigated the effects of component failure and/or reduced the downtime required to recover after component failure, it can be said to be
Highly available
If a system can continue to function despite the failure of a critical component, it can be said to be
Fault tolerant
Which is easier to build and architect: a highly available system, or a fault tolerant system?
A highly available system is easier to build. Also less expensive.
What is the process by which a completely failed system protects critical system data to build a new system in the event of failure?
Disaster recovery
Do you need a DR plan if you’ve carefully crafted a HA or FT system?
Definitely.
When evaluating a DR solution, the term that identifies the maximum allowable timeframe between system failure and the restoration of the system to an operational state.
RTO - Recovery Time Objective
When evaluating a DR solution, the term that identifies the total amount of data you’ll lose based on time between failure and last successful backup.
RPO - Recovery Point Objective
If data is local to a resource and is lost when the resource is released, it can be considered
Ephemeral
If data exists in a secondary location as it’s passed between sources, it can be considered
Transient
If data exists in a durable location which can survive system starts, stops, restarts, or power events, it can be considered
Persistent
What’s an example of an ephemeral data store
Instance store volume, cache
What’s an example of a transient data store
Queues (SQS, MQ), Kinesis Data Streams
What’s an example of a persistent data store
EBS, EFS, S3
What’s a common advantage of ephemeral storage
Speed!
What’s a common disadvantage of persistent storage
Lack of speed, compared to ephemeral volumes.
What’s the most common reason transient storage is used
Decoupling application components to help drive HA/FT designs
What OSI layer represents the software stored on your device, and is capable of communicating in binary across a shared medium?
1 - Physical
What OSI layer provides the ability to address devices uniquely, using a MAC address?
2 - Data link
What OSI layer adds IP addresses?
3 - Network
Is IP designed to be reliable?
Nope. Doesn’t test for receive, doesn’t account for ordering.
