💸Exam Guide: Cloud Practitioner
Domain 4: Billing, Pricing, and Support
📘Task Statement 4.1
Domain 4 is the “money money money” part of Cloud Practitioner: not glamorous, but absolutely testable—and very real in the workplace.
Can you pick the most cost-effective option without breaking the workload requirements?
🎯 What Is This Task Testing?
You must be able to compare AWS pricing across:
- Compute Purchasing Options (On-Demand, Reserved Instances, Spot, Savings Plans, Dedicated Hosts/Instances, Capacity Reservations)
- Data Transfer Charges (inbound vs outbound, same Region vs cross-Region)
- Storage Pricing Options and Tiers (especially Amazon S3 classes)
1) 🖥️ Compute Purchasing Options
On-Demand Instances
Pay for compute capacity by the hour/second (service-dependent), with no long-term commitment.
Use On Demand Instances When:
- workloads are short-term, spiky, or unpredictable
- you’re developing/testing
- you can’t commit to steady usage yet
“no commitment,” “unpredictable,” “temporary” → On-Demand.
Reserved Instances (RIs)
Commit to a term (commonly 1 or 3 years) for discounted pricing on eligible services (frequently associated with EC2, and also used in other contexts like RDS).
Use Reserved Instances When:
- workload is steady and predictable
- you want a discount in exchange for commitment
“steady usage,” “known baseline,” “commit for lower cost” → Reserved Instances.
Reserved Instance flexibility
RIs can offer flexibility depending on the RI type and scope. At the exam level, know:
- Some RIs can apply across different instance sizes within an instance family (size flexibility), depending on configuration.
- The more specific the reservation, the less flexible it is, but it can better match a known workload.
“need flexibility as instance sizes change” → think RI flexibility (or Savings Plans).
Reserved Instances in AWS Organizations
In an AWS Organizations setup, RI benefits can be shared across accounts (within the organization) depending on configuration.
“multiple accounts under one org want to share discounts” → RIs in AWS Organizations.
Savings Plans
A flexible pricing model where you commit to a consistent amount of compute usage (measured as $/hour) over 1 or 3 years.
Use Savings Plans When:
- you want RI-like savings but with more flexibility
- you have steady compute spend, even if instance types may change
“commit to spend, want flexibility across compute” → Savings Plans.
Spot Instances
Purchase unused EC2 capacity at deep discounts, but AWS can reclaim the capacity with short notice.
Use Spot Instances When:
- workloads are fault-tolerant and can handle interruptions
- batch processing, big data jobs, CI/testing, containerized stateless workloads
“can be interrupted,” “batch/fault-tolerant,” “lowest cost compute” → Spot.
Dedicated Instances
EC2 instances that run on hardware dedicated to a single customer, but the hardware is still managed by AWS and may be shared across instances within your account.
Use Dedicated Instances When:
- you need single-tenant hardware for compliance or licensing reasons
“single-tenant instances” → Dedicated Instances.
Dedicated Hosts
A physical server dedicated to you, giving you more visibility and control over how instances are placed on that server (commonly used for licensing requirements).
Use Dedicated Hosts When:
- you need to use certain bring-your-own-license (BYOL) models that require dedicated physical hardware
- you need control at the host level
“BYOL requires dedicated server/host” → Dedicated Hosts.
Capacity Reservations
Reserve capacity in a specific AZ for EC2, ensuring it’s available when you need it.
Use Capacity Reservations When:
- you must guarantee capacity (regulatory, business-critical events, predictable spikes)
- you need capacity in a particular Availability Zone
“must have capacity available in this AZ” → Capacity Reservations.
2) 🌐 Data Transfer Charges
Data transfer pricing is a frequent exam topic because it surprises people in real life.
Inbound vs Outbound
- Inbound data transfer (into AWS) is often lower cost or free, depending on the service and scenario.
- Outbound data transfer (out of AWS) is more commonly charged.
“moving data from one Region to another” → data transfer charges apply.
“sending data out to end users on the internet” → outbound/egress costs.
3) 🗂️ Storage Options and Tiers
Storage pricing depends mainly on:
- how frequently you access data
- how quickly you need retrieval
- durability/resiliency design (e.g., multi-AZ vs single-AZ)
- storage amount, requests, and retrieval charges (service-dependent)
Amazon S3 storage classes
- S3 Standard: frequent access
- S3 Intelligent-Tiering: unknown/changing access patterns
- S3 Standard-IA / One Zone-IA: infrequent access (One Zone = lower cost, single AZ)
- S3 Glacier tiers: archival storage (lowest cost, slower retrieval options)
“archive for years, rarely accessed” → Glacier / Deep Archive.
“unknown access pattern” → Intelligent-Tiering.
“cheaper storage but still quickly accessible” → Standard-IA (or similar).
✅ Quick Exam-Style Summary
- On-Demand: short-term, unpredictable, no commitment
- Reserved Instances: steady workloads, commit for discount (some flexibility, can share in AWS Organizations)
- Savings Plans: commit to compute spend with flexibility
- Spot: biggest discounts, interruption-tolerant workloads
- Dedicated Instances/Hosts: single-tenant needs (Hosts have most control for licensing)
- Capacity Reservations: guarantee capacity in a specific AZ
- Data transfer: inbound often cheaper, outbound/cross-Region commonly costs more
- Storage tiers: pay less for infrequent/archive, trade off access speed and sometimes resiliency
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