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What is EC2 ?
It is a web service that provides re-sizable compute capacity in the cloud.
What are the 4 EC2 Pricing options ?
1) On Demand 2) Reserved 3) Spot 4) Dedicated Hosts
On-Demand - Use cases
1) Perfect for users that want the low cost and flexibility of Amazon EC2 without any upfront payments. 2) Applications with short term, spikey or unpredictable workloads that cannot be interrupted. 3) Applications being developed or tested for the first time. (Great for learning)
Reserved - Use Cases;
1) Applications with steady state requirements. 2) Applications with predictable usage. 3) Users can make upfront payments.
What are the three reserved instance (RI) types?
1) Standard RI 2) Convertible RI 3) Scheduled RI
Discounts on RI ?
Standard RI - 75% discount off (3-year contract) Convertible RI 54% discount off (3-year contract)
What is a scheduled RI ?
An EC2 instance that is only available to launch within the time window you reserve. * It allows you to match your capacity reservation to a predictable recurring schedule that only requires a fraction of a day, month or year.
Use Cases for Spot Instances?
1) Applications that have flexible start/finish time. 2) Applications that are only feasible at very low compute prices. 3) Users with an urgent need for large amounts of additional computing capacity.
Use Cases for dedicated hosts?
1) Useful for customers and licenses who are not eligible to support multi-tenant virtualisation 2) Can be purchased on demand (hourly) 3) can be purchased as a reservation for up to 70% off the on-demand price.
EC2 Instances Types: FightDrMcPX
F = FPGA I = IOPS G = Graphics H = High Disk Throughput T = Cheap General Purpose D = Density R = Ram M= Main choice for general purpose apps: C = Compute P = Graphics (Pics) X = Xtreme Memory
Spot Instance Termination - When are you charged?
If a spot instance is terminated by AWS EC2 then you are not charged for the partial hour of usage. If you terminate the instance yourself then you will be charged for the complete hour in which the instance ran.
What does the status system check mean on an EC2 instance?
This check verifies that your instance is reachable. We test that we are able to get network packets to your instance. * similar to a hypervisor check.
What does the instance system check mean on an EC2 instance?
This check verifies that your instance’s operating system is accepting traffic.
What is EC2 Termination Protection?
Prevents the deletion of an instance, it’s turned off by default.
Role assignment
Roles can be assigned on creation or post creation.
Check an EC2 metadata
curl http://169.254.169.254/latest/meta-data/
What is an EC2 clustered placement group?
A group of instances within a single availability zone. * Recommended for: Low network latency. * Recommended for high network throughput.
What is an EC2 spread placement group?
A group of instances that are placed on distinct hardware. Recommended for applications that have a number of critical instances that should be kept separate from each other. * Can span multiple availability zones.
Placement group naming
Must be unique to your account.
Only certain types of instances can be launched in a placement group.
Compute optimised GPU Memory optimised Storage optimised
Placement groups merges and movements
You cannot merge a placement group. You cannot move an existing instance into a placemenr group. You can create an AMI from an existing instance then launch a new instance from the AMI into a placement group.
Describe EC2 On Demand Instances:
Allows to pay a fixed rate by the hour, with no commitment. Recommended for: Applications with unpredictable workloads Applications that can’t be interrupted
Describe EC2 Reserved Instances.
Provides a capacity reservation, with significant discount. Contract terms are 1 or 3 years. - Applications with Predictable workloads. There are 3 types: - Standard - Convertible - Scheduled
What are the 3 types of EC2 Reserved Instances:
Standard: - 75% of discount from On Demand price Convertible: - You may convert one instance to another. Scheduled: - Works at specific time intervals.
Describe EC2 Spot Instances
Unused instances on which you bid on. AWS will assign them to you if your target price is above the spot price. Workload will run as long as the price is below. Ideal for workloads that can be interrupted.
Describe EC2 Dedicated host instances
Used for regulatory applications. Can be purchased on demand.
Can you encrypt the root device volume?
Yes, from the beginning or at a later time
What is the default action for the volumes when you terminate an EC2 instance?
To delete the root volume, and keep the rest.
What’s the difference between Security Group rules and NACLs (network access controls LIsts)?
Security groups rules are stateful: once you allow inbound traffic to a port, outbound traffic is allowed. NACLs rules are state-less: you have to permit inbound and outbound traffic rules.
How does traffic behaves on security Groups by default?
All traffic is blocked, you must create “allow” rules to allow specific traffic.
* What types of Storage are available for EC2 Instances?
EBC and Instance Store
* How is sometimes called Instance Store?
Ephemeral Storage, since it is not persistent.
* What is the difference between EBS and Instance Store?
If an instance store backed AMI fails at the Hypervisor, data will be lost. None will lose data if rebooted. EBS can be stopped, Instance Store can’t. You can’t keep an Instance Store volume. Instance Store volumes can’t be seen in Volumes.
* What is ENI?
Elastic Network Interface: - provides a primary private IPv4 address - One or more private IPv4 address - One elastic IPv4 per private address - One or more IPv6 address - One or more security groups - A MAC Address - A source/destination check flag - A description.
* What is Enhanced Networking?
It’s a method to provide higher network performance to your EC2 instance, only available to some instance types.
* What does Enhanced Networking SR-IOV stands for?
Single root I/O Virtualization
* What options of Enhanced Networking exist?
Elastic Network Adapter (ENA) and Virtual Function (VF)
* What is the supported speed of ENA?
100 Gbps
* What is EFA and what is it’s purpose?
Elastic Fabric Adapter,enhance HPC and ML workloads., - Low latency - bypasses OS - Only Linux support
What are the uses of ENI vs ENA vs EFA?
ENI - additional network interfaces. ENA - High performance Network interface EFA - HPC or ML workloads.
Can versioning be disabled?
Once enabled, versionin can’t be disabled, just suspended.
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