EC2 Flashcards
What is EC2
IaaS
Resizable compute capacity in the cloud with a pay-as-you-go billing model
What are the four billing models on EC2
- On Demand: Charged by hour or second - Reserved: Reserve at 1 or 3 years with up to 75% discount - Spot instances Bid a price you're willing to pay - Dedicated hosts: Rent a physical server Allow using existing server bound software licenses Can be on demand
What pricing model would be best suitable for applications with spiky unpredictable loads?
On demand
What pricing model would be best suitable for applications with flexible start and end times, and only feasible at low compute prices loads?
Spot instances
What pricing model would you use for software with regulatory requirements that do not support multi-tenancy virtualization?
Dedicated hosts
What three types are available with reserved instances?
- Standard: Up to 75% discount - Convertible reserved instances: Up to 54% discount - Scheduled reserved instances
What are some attributes that you can change in a Convertible reserved instance?
Instance family
OS
Tenancy
Is termination protection turned on or off by default?
Turned off
What is the default action for EBS backed instances when instances are terminated?
Delete the EBS volume, but behavior can be disabled
How can you encrypt the EBS root volume of a default AMI?
During AMI creation via console or API, or third party tools (bit locker)
What rules does a default security group contain?
Inbound blocked by default
Outbound traffic allowed
How much time does it take for changes to Security Groups to be reflected?
Instant
T/F Security Groups are stateless
False, security groups are stateful
What does it mean for a firewall to be stateful?
It keeps track of what comes in and allows responses to those packages to go back.
Can you block specific IPs with security groups?
No
How many EC2 instances can be attached to a security group
As many as you want
How many Security groups can you assign to an EC2 instance?
Up to 5 at a time (can be expanded up to 16 in extreme situations)
In how many AZs are EBS volumes replicated?
- EBS volumes are only replicated within the AZ
What are the main four types of EBS storages?
- General Purpose (gp2)
- Provisioned IOPS (io1)
- Throughput Optimized HDD (st1)
- Cold HDD (sc1)
What is an EBS snapshot
An incremental photograph of the disk at a point in time. Stored in S3. Available within AZ.
How would you move an EBS volume of AZ? And Region?
Take Snapshot > Take AMI > Launch Instance in other AZ
For moving of region, move AMI first
What some attributes that can be changed on the fly on an EBS volume?
Size and storage type
How can you encrypt an unencrypted root EBS volume?
Take a snapshot > copy the snapshot with encryption > create AMI from snapshot
What is the difference between an AMI Instance Store and an EBS backed volume
Instance store backed instances cannot be stopped, if the underlying host fails, data is deleted. With EBS backed instances they can remain in existence
What is an ENI?
Elastic Network Interface
Virtual equivalent of a network card
How does Enhanced Networking work?
Uses I/O virtualization (SR-IOV)
Higher I/O performance and lower CPU utilization
Use for good network performance
What types of Enhanced Networking are there
- Elastic Network Adapter (ENA):
Up to 100Gbps for supported instance types - Inter 822599 Virtual Function (VF):
Legacy, up to 10Gbps
