An engineer’s guide to cloud capacity planning is a wonderful article that discusses on-demand provisioning, horizontal and vertical scaling and how to estimate performance of your infrastructure.
Selecting a cloud provider reviews Etsy's decisionmaking around self-hosted infrastructure versus cloud hosting. They put together an architectural model and ultimately decided to start migrating over to Google Cloud Platform.
Going Multi-Cloud with AWS and GCP: Lessons Learned at Scale covers the compute, networking, persistent storage, billing and failover aspects of using more than one infrastructure provider.
Auth0 Architecture: Running In Multiple Cloud Providers And Regions explains their multi-cloud architecture and how it has evolved over the past several years.
How Netlify migrated to a fully multi-cloud infrastructure is another story post about developing a multi-cloud architecture and the considerations for disaster recovery, databases and testing.