EC2 - Instance Purchasing Options/IP Address Charges Flashcards
What is the On-Demand pricing model for EC2?
On-Demand EC2 instances allow you to pay for compute capacity by the second (for Linux/Windows) or by the hour (for other OS). It is ideal for unpredictable workloads with no long-term commitment.
What are Reserved Instances (RIs) in EC2?
Reserved Instances allow you to reserve EC2 instances for one or three years. You get a discount (up to 72%) compared to On-Demand pricing in exchange for a commitment to use specific instance types and regions.
What is a Convertible Reserved Instance?
Convertible Reserved Instances allow you to change instance types, families, operating systems, or the scope of your reservation (e.g., region or tenancy) during the term. These offer up to 66% discount.
What are EC2 Savings Plans?
Savings Plans provide discounts (up to 70%) for committing to a specific amount of compute usage (in dollars) over one or three years, without locking into specific instance types. You can switch instance families, operating systems, and regions.
What are Spot Instances and when are they suitable?
Spot Instances are very cost-efficient (up to 90% off On-Demand prices) but can be terminated anytime if the Spot price exceeds your bid. Suitable for workloads that are flexible and resilient to interruptions, such as batch jobs or data analysis.
What is an EC2 Dedicated Host?
A Dedicated Host is a physical server that you can reserve for your exclusive use. Ideal for workloads with specific compliance requirements or where you need to use existing server-bound software licenses (e.g., BYOL - Bring Your Own License).
What is the difference between Dedicated Hosts and Dedicated Instances?
Dedicated Instances run on hardware that’s dedicated to you but may share the hardware with other instances. Dedicated Hosts provide visibility and control over the physical server and are used for specific licensing or compliance needs.
What is an EC2 Capacity Reservation?
Capacity Reservations allow you to reserve compute capacity in a specific Availability Zone (AZ) without a commitment to use it. This ensures that your instances will be available when needed but with no discount.
When should you use Reserved Instances?
Use Reserved Instances for steady-state workloads that are predictable over one or three years, such as databases or applications that need consistent compute capacity.
When should you use Spot Instances?
Use Spot Instances for flexible, short-term workloads that can tolerate interruptions, such as data analysis, image processing, and batch jobs.
How does pricing compare between different EC2 purchasing options?
On-Demand: No commitment, highest price.
Reserved Instances: Up to 72% discount, commitment for 1-3 years.
Convertible Reserved Instances: Up to 66% discount, more flexibility.
Savings Plans: Similar discounts to Reserved Instances but based on usage in dollars, not instance type.
Spot Instances: Up to 90% discount, risk of termination.
Dedicated Hosts: Most expensive, for specific licensing and compliance needs.
Capacity Reservations: No discounts, but guarantees availability in a specific AZ.
How can I think of EC2 purchasing options in terms of a resort analogy?
On-Demand: You come to the resort whenever you like and pay full price.
Reserved Instances: You commit to staying at the resort for 1-3 years and get a discount.
Savings Plan: You commit to spending a certain amount at the resort, but you can switch rooms over time.
Spot Instances: You get last-minute discounts, but risk being kicked out if someone bids higher.
Dedicated Hosts: You book the entire resort for yourself.
Capacity Reservations: You reserve a room, but you pay whether you stay in it or not.
What should you keep in mind when using Public IPv4 in AWS?
Public IPv4 addresses are charged at $0.005 per hour, or approximately $3.60/month.
Be mindful of exceeding the free tier (750 hours/month for EC2).
Non-EC2 services like load balancers or RDS can incur additional charges for Public IPv4 addresses without a free tier.
Monitor and manage your Public IPv4 usage carefully to avoid unexpected costs. This can be done through AWS billing insights and IPAM.
