There is also a version of this article on Strategic Blue blog

Intro

At Strategic Blue, we care about the money, and we’ve been collecting prices of AWS and other cloud vendors for a while. Another characteristic of Strategic Blue is that we are curious and love digging into the numbers, checking common assumptions, and find new ways to save money.

This article is one such analysis done to understand how much a Windows license costs on AWS and understand if Azure Windows Licenses are cheaper (as per common assumption).

Executive Summary

• AWS Windows license pricing is very consistent, and only depends on the number of CPU for “current generation VM”.
• AWS Windows license pricing is extremely inconsistent for older generations
• Windows License price on AWS does not change between Regions
• Surprise, Windows license on AWS and Azure is the same. i.e. Microsoft Windows license on Azure cost the same as AWS. (Tested on a subset of Azure pricing, but the numbers match for three decimals)

The price is per hour in US$ The c4.8xlarge have different prices per region, don’t ask me why

POMO

Purpose: to find if a good approximation of the cost of Windows licensing on AWS Objective: being able to separate infrastructure and licensing costs Method: SQL queries on AWS pricing table Outcome: A Windows license price list for AWS

Assumptions:

• Work is done on shared instances
• The licence cost is the difference between a windows instance price - Linux instance price
• Based on march 2020 prices

Other possible experiments:

• check RI pricing logic - are RI calculated on the infrastructure cost then a license is added
• deduce RedHat/Suse license prices
• deduce the SQL Server license prices
• improve the queries
• make this analysis automated

What can a Windows licensed instance run on AWS:

from https://aws.amazon.com/ec2/pricing/on-demand/ The pricing below includes the cost to run private and public AMIs on the specified operating system (“Windows Usage” prices apply to Windows Server 2003 R2, 2008, 2008 R2, 2012, 2012 R2, 2016, and 2019).

The dataset

The dataset is coming from Strategic Blue pricing data originated from the AWS price API. I did some changes to make it manageable in a PostgreSQL on my desktop.

The column used are instance, os, software, region, hourly_price, upfront_price, current_generation, term, tenancy, effective_month, license_model, purchase_option, offering_class, key.

Investigation

Regions

How many regions do we have in the table: 21

Asia Pacific (Tokyo), EU (London), US East (N. Virginia), Asia Pacific (Singapore), South America (Sao Paulo), Asia Pacific (Osaka-Local), US West (Oregon), Asia Pacific (Seoul), EU (Paris), Asia Pacific (Hong Kong), Canada (Central), AWS GovCloud (US-West), US East (Ohio), EU (Ireland), US West (N. California), Asia Pacific (Mumbai), Asia Pacific (Sydney), EU (Frankfurt), AWS GovCloud (US-East), Middle East (Bahrain), EU (Stockholm)

This information is essential as in most queries, the count column, represents the number of regions a specific price is valid. If count is 21, then all regions are charged the same.

queries

SELECT  COUNT(DISTINCT region)
from awspricing;

SELECT  DISTINCT region
from awspricing;

Getting the family, generation and size of instances

SELECT
  regexp_replace (t1.instance, '\..*$', '') gen,
  regexp_replace (t1.instance, '^[^\.]*.', '') size
FROM awspricing t1

Joining the rows of the window with the Linux rows

We assume that the Windows license price = Windows hourly price - Linux hourly price.

So in Database talk, we need to join the table awspricing with itself but connecting Windows rows with Linux rows and being able to get the Windows licence price.

To limit the quantity of information and focus on recent instances, we are going to only choose shared instances, of the current generation, without any additional software (e.g. SQL server). The pricing used is on-demand as it is the baseline for all other prices.

SELECT
  regexp_replace (t1.instance, '\..*$', '') gen,
  regexp_replace (t1.instance, '^[^\.]*.', '') size,
  round((t1.hourly_price - t2.hourly_price)::numeric, 3) AS WinLicPrice,
  count(*)
FROM awspricing AS t1 JOIN awspricing AS t2
  ON t1.instance = t2.instance
  AND t1.software = t2.software
  AND t1.region = t2.region
  AND t1.tenancy = t2.tenancy
  AND t1.license_model = t2.license_model
  AND t1.purchase_option = t2.purchase_option
  AND t1.offering_class = t2.offering_class
  AND t1.key = t2.key

WHERE t1.os = 'Windows'
  AND t2.os = 'Linux'
  AND t1.software = 'NA'
  AND t1.key = 'OD'
  AND t1.tenancy = 'Shared'
  AND t1.current_generation = 'Yes'
  AND regexp_replace (t1.instance, '^[^\.]*.', '') <> 'unit'

GROUP BY WinLicPrice, size, gen

ORDER BY size, count DESC, WinLicPrice, gen
;

discoveries / anomalies

• For non-current-generation, the numbers are all over the place
• For current-generation, the numbers are consistent in all regions and size
• Only size (i.e. vcpu) matters
• c4 8xlarge is not consistent
• d2 is the current generation, but should not be in my opinion
• t2 and t3 and t3a have dedicated pricing, probably due to the nature of their CPU bursting capabilities

Query excluding the anomalies above

SELECT
  regexp_replace (t1.instance, '^[^\.]*.', '') size,
  round((t1.hourly_price - t2.hourly_price)::numeric, 3) AS WinLicPrice,
  count(*)
FROM awspricing AS t1 JOIN awspricing AS t2
  ON t1.instance = t2.instance
  AND t1.software = t2.software
  AND t1.region = t2.region
  AND t1.tenancy = t2.tenancy
  AND t1.license_model = t2.license_model
  AND t1.purchase_option = t2.purchase_option
  AND t1.offering_class = t2.offering_class
  AND t1.key = t2.key

WHERE t1.os = 'Windows'
  AND t2.os = 'Linux'
  AND t1.software = 'NA'
  AND t1.key = 'OD'
  AND t1.tenancy = 'Shared'
  AND t1.current_generation = 'Yes'
  AND regexp_replace (t1.instance, '\..*$', '') <> 't2'
  AND regexp_replace (t1.instance, '\..*$', '') <> 't3'
  AND regexp_replace (t1.instance, '\..*$', '') <> 't3a'
  AND regexp_replace (t1.instance, '\..*$', '') <> 'd2'
  AND regexp_replace (t1.instance, '^[^\.]*.', '') <> 'unit'

GROUP BY WinlicPrice, size --, gen

ORDER BY size, count DESC, winlicprice --, gen
;

Again, the c4.8xlarge have different prices per region… don’t ask me why

t2 and t3 and t3a

SELECT
  regexp_replace (t1.instance, '\..*$', '') gen,
  regexp_replace (t1.instance, '^[^\.]*.', '') size,
  round((t1.hourly_price - t2.hourly_price)::numeric, 3) AS WinLicPrice,
  count(*)
FROM awspricing AS t1 JOIN awspricing AS t2
  ON t1.instance = t2.instance
  AND t1.software = t2.software
  AND t1.region = t2.region
  AND t1.tenancy = t2.tenancy
  AND t1.license_model = t2.license_model
  AND t1.purchase_option = t2.purchase_option
  AND t1.offering_class = t2.offering_class
  AND t1.key = t2.key

WHERE t1.os = 'Windows'
  AND t2.os = 'Linux'
  AND t1.software = 'NA'
  AND t1.key = 'OD'
  AND t1.tenancy = 'Shared'
  AND t1.current_generation = 'Yes'
  AND regexp_replace (t1.instance, '\..*$', '') IN ('t2', 't3', 't3a')
  AND regexp_replace (t1.instance, '^[^\.]*.', '') <> 'unit'

GROUP BY WinlicPrice, size ,gen

ORDER BY gen, size, count DESC, winlicprice
;

Monthly and yearly calculations

SELECT
  regexp_replace (t1.instance, '\..*$', '') gen,
  regexp_replace (t1.instance, '^[^\.]*.', '') size,
  round((t1.hourly_price - t2.hourly_price)::numeric, 3) AS WinLicPrice,
  round((t1.hourly_price - t2.hourly_price)::numeric, 3) * 730 AS WinLicPriceMonthly,
  round((t1.hourly_price - t2.hourly_price)::numeric, 3) * 730 * 12 AS WinLicPriceYearly,
  count(*)
FROM awspricing AS t1 JOIN awspricing AS t2
  ON t1.instance = t2.instance
  AND t1.software = t2.software
  AND t1.region = t2.region
  AND t1.tenancy = t2.tenancy
  AND t1.license_model = t2.license_model
  AND t1.purchase_option = t2.purchase_option
  AND t1.offering_class = t2.offering_class
  AND t1.key = t2.key

WHERE t1.os = 'Windows'
  AND t2.os = 'Linux'
  AND t1.software = 'NA'
  AND t1.key = 'OD'
  AND t1.tenancy = 'Shared'
  AND t1.current_generation = 'Yes'
  AND regexp_replace (t1.instance, '^[^\.]*.', '') <> 'unit'

GROUP BY WinLicPrice, size, gen

ORDER BY size, count DESC, WinLicPrice, gen