Question: What is the pricing model for Amazon ElastiCache Reserved Instances (RI)?

Answer

Amazon ElastiCache offers different pricing models depending on customers' needs, including On-Demand and Reserved Instances. The latter can provide significant savings compared to On-Demand instances.

Reserved Instances (RIs) require a one-time, upfront payment and offer a significant discount compared with the hourly charge for On-Demand instances. There are three types of RIs - All Upfront, Partial Upfront, and No Upfront:

1. All Upfront: You make the entire payment at the start of the term, with no other costs or additional hourly charges incurred for the remainder of the term.
2. Partial Upfront: A portion of the cost has to be paid upfront and the remaining hours in the term are billed at a discounted hourly rate.
3. No Upfront: Costs are distributed evenly across each hour over the term of reservation.

The duration of the term also impacts the cost of RIs, with longer terms providing a greater discount. Currently, Amazon offers 1-year and 3-year term options.

For specific prices, it's best to directly refer to Amazon's official ElastiCache Pricing page as rates can vary by region and instance type.

# Example Python code using boto3 to get RI pricing
import boto3

pricing = boto3.client('pricing', region_name='us-east-1')

response = pricing.get_products(
    ServiceCode='AmazonElastiCache',
    Filters=[
        {'Type': 'TERM_MATCH', 'Field': 'termType', 'Value': 'Reserved'},
    ],
)

for product in response['Products']:
    # Print out product details here...

Note: You'd need to parse the JSON returned from the get_products call to get the actual pricing information. Check for updates in AWS SDKs for possible changes.