An online retailer usually experiences a big surge in sales during festive periods like Christmas and during other online shopping events such as "Black Friday" and "Singles Day", but lower sales during most other months. To minimise downtime and capital IT expenditure, and to maximise customer experience and facilitate high and low sales across different months, the online retailer intends to host its ecommerce application in the cloud. Formulate the relationship among strategy, architecture and infrastructure by identifying the most relevant architectural configuration (for example, decentralised, centralised) along with appropriate justifications that will help the online retailer to achieve its business objectives.