Purchasing Options

  • On-Demand Instances

    • Short workload, predictable pricing

    • Linux & Windows - billing per second after the first minute

    • Other OS - billing per hour

    • Highest cost but not upfront payment

    • No long-term commitment

    • Recommended for short-term uninterrupted workloads where you can't predict how the application will behave

  • Reserved (1 & 3 years)

    • Reserved Instances - long workloads

      • Up to 72% discount compared to On-Demand

      • Reserve a specific instance attributes (Intsance Type, Region, Tenancy, OS)

      • Reservation Period - 1 year discount, 3 years bigger discount

      • Payment Options - discount depends on No Upfront, Partial Upfront or Full Upfront

      • Reserved Instance's Scope - Regional or Zonal

      • Recommended for steady state usage applications (e.g. databases)

      • You can buy & sell in the Reserved Instance Marketplace

    • Convertible Reserved Instance - long workloads with flexible instances

      • Can change the EC2 instance type, instance family, OS, scope and tenancy

      • Less of a discount for more flexibility

  • Savings Plans (1 & 3 years)

    • Commitment to an amount of usage, long workload

    • Discount based on long-term usage (same as Reserved Instances)

    • Commit to a certain type of usage (e.g. $10/hour for 1 or 3 years)

    • Usage beyong EC2 Savings Plan is billed at the On-Demand price

    • Locked into a specific instance family & AWS Region (e.g. M5 in us-east-1)

    • Flexible across:

      • Instance size (e.g. m5.xlarge, m5.2xlarge)

      • OS (e.g. Linux, Windows)

      • Tenancy (Host, Dedicated, Default)

  • Spot Instances

    • Short workloads, cheap, can lose instances (less reliable)

    • Up to 90% discount compared to On-Demand

    • Instances you can lose at any point of time if your max price is less than the current Spot price

    • Most cost efficient instances in AWS

    • Useful for workloads which are resilient to failure

      • Batch jobs

      • Data analysis

      • Image processing

      • Any distributed workloads

      • Workloads with a flexible start and end time

    • Not suitable for critical jobs or databases

  • Dedicated Hosts

    • Book an entire physical server, control instance placement

    • Address compliance requirements and use your server bound software licenses (per-socket, per-core, per-VM etc)

    • Purchasing Options:

      • On-demand - pay per second

      • Reserved - 1 or 3 year (No Upfront, Partial Upfront, Full Upfront payment)

    • Most expensive option on AWS

  • Dedicated Instances

    • No other customers will share your hardware

    • May share hardware with other instances in the same account

    • No control over instance placement (can move hardware after Stop/Start)

Characteristics
Dedicated Instances
Dedicated Hosts

Enabled use of dedicated physical servers

Yes

Yes

Per instance billing (subject to $2 per region fee)

Yes

No

Per host billing

No

Yes

Visibility of sockets, cores, host ID

No

Yes

Affinity between a host and instances

No

Yes

Targeted instance placement

No

Yes

Automatic Instance Placement

Yes

Yes

Add capacity using an allocation request

No

Yes

  • Capacity Reservations

    • Reserve On-Demand instances capacity in a specific AZ for any duration

    • Always have access to EC2 capacity when you need it

    • No time commitment (create/cancel any time), no billing discounts

    • Combine with Regional Reserved Instances and Savings Plans to benefit from billing discounts

    • You're charged at the On-Demand rate whether you run instances or not

    • Suitable for short-term, uninterrupted workloads that needs to be in a specific AZ

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