Skip to content

045 ec2 instances purchasing options

Options

On-Demand Instances: short workload, predictable pricing, pay by second

Reserved (1 or 3 year): long workloads, flexible instances

Savings Plans (1 or 3 year): long workload, commitment to an amount of usage

Spot Instances: short workloads, cheap, can lose instances

Dedicated Hosts: book an entire physical server

Dedicated Instances

Capacity Reservations: reserve capacity in a AZ for any duration

Details

On demand

  • Pay for what you use
  • highest cost, no upfront payment
  • no leng-term commitment

For short-term, un-interrupted workloads, where you can’t predict how app will behave

Reserved Instances

  • 72% discount vs on-demand
  • a specific instance attributes
  • reservation period: 1 yr | 3 yr
  • payment options: no upfront | partial upfront | all upfront
  • scope: regional | zonal
  • buy and sell reserved instance in marketplace

For steady-state usage application (db)

Convertible reserved instance

  • Can change EC2 instance type, family, OS, scope and tenancy
  • 66% discount

Savings Plans

  • 72% discount
  • commit to a dollar amount of usage: $?/hour for 1 or 3 yr
  • usage beyond Savings Plans is billed at on-demand price

Locked:

  • instance family
  • region

Flexible:

  • instance size (e.g. m5.xlarge m5.2xlarge)
  • OS
  • tenancy

Spot Instances

  • 90% discount
  • instances that you can lose at any point of time
  • most cost-efficient instances in aws

For workloads that are resilient to failure

  • batch jobs
  • data analysis
  • image processing
  • any distributd workloads
  • flexible start/end

Not for critical jobs / DBs

Dedicated Hosts

  • a physical server
  • purchase options
    • on-demand
    • reserved
  • the most expensive option

For software that have complicated licensing model and companies that have strong regulatory or compliance needs

Dedicated Instances

  • instances run on hardware that’s dedicated to you
  • may share hardware with other instances
  • no control over instance placement

Capacity Reservations

  • reserve on-demand instances in a specific AZ for any duration
  • you always have access to EC2 when you need it
  • combine with Regional Reserved Instances and Savings Plans to benefit from discount
  • charges at on-demand rate whether you run or not

For short-term, uninterrupted workloads

How to choose purchasing option

On demand: no plan, full price

Reserved: plan, discount

Savings Plans: certain amount, period & type

Spot instances: highest bidder keeps the room, kicked out at any time

Dedicated Hosts: book an entire building

Capacity Reservations: you book a room for a period with full price