Zero-Egress Architecture with Cloudflare R2#

Every major cloud provider charges you to download your own data. AWS S3 charges $0.09/GB. Google Cloud Storage charges $0.12/GB. Azure Blob charges $0.087/GB. These egress fees are the most unpredictable line item on cloud bills – they scale with success. The more users download your data, the more you pay.

Cloudflare R2 charges $0 for egress. Zero. Unlimited. Every download is free, whether it is 1 GB or 100 TB. R2 uses the S3-compatible API, so existing tools and SDKs work without changes. This single pricing difference changes how you architect storage, serving, and cross-cloud data flow.

Choosing Kubernetes Storage#

Storage decisions in Kubernetes are harder to change than almost any other architectural choice. Migrating data between storage backends in production involves downtime, risk, and careful planning. Understand the tradeoffs before provisioning your first PersistentVolumeClaim.

The decision comes down to five criteria: performance (IOPS and latency), durability (can you survive node failure), portability (can you move the workload), cost, and access mode (single pod or shared).

Storage Categories#

Block Storage (ReadWriteOnce)#

Block storage provides a raw disk attached to a single node. Only one pod on that node can mount it at a time (ReadWriteOnce). This is the most common storage type for databases, caches, and any workload that needs fast, consistent disk I/O.