EC2 Purchase Options

On-Demand

• you rent a room, but you need to move to a new room every time you left
• per-second billing while it’s running
• other associated resource may charge externally
• No interruption capacity reservation/ upfront cost/ discount
• suitable for short-term workload/ uncertainty

Spot

• you rent the left-over room, if they need it, you kick out until they left
• selling the spare capacity in the host
• spot price > your maximum price, your instances terminate
• very cheap (90% cheaper) if you can be interrupted
• Never use spot for workloads which can’t tolerate interruptions
• anything is stateless

Standard Reserved

• you commit that you will use the resources for a length of time, in exchange with a cheaper price = subscription
• For long term consistent usage (1/3 yrs)
• you will pay for the reservation if you use the resource
• more upfront you pay, cheaper the free per second

Schedule Reserved instances

• specify the time-span you will used
• eg you only needs a computing something every weekend for certain number of hours recursively

Capacity reservation

• just for the capacity where you cannot justify a long-term commitment

Dedicated Hosts

• you rent the whole building
• pay for the host itself that come with all the resources and machine, no instance charges
• physical server isolation
• host affinity = links instances to hosts = remain on same host even stop & start ⇒ licensing implication
• you can use the sockets/ cores of the machine you pay with the licensing requirement
• capacity management required
• with AMI limits and not support RDS/ placement group

Dedicated instances

• you rent a room, always stay in this room
• You don’t own, or share the host
• physically isolated at the host hardware level from instances that belong to other AWS accounts
• keep that part of physical intra-structure is for your own use

Saving plan

• hourly commitment for a 1/3 year term
• 2 type of resevations
  1. reservation of general compute $ amounts
  2. specific EC2 savings Plan - flexibility on size & OS (also for fargate/ Lambda)
• commit the minimum spend on all these services with saving plan, discount if the commitment is achieved