C4/Diagram/Deployment

• Deployment diagram (C4 diagram)

  • Overview

    • A supporting C4 diagram mapping software containers to infrastructure: regions, clusters, nodes, PaaS services, serverless targets, networking boundaries, and similar deployment concerns.
    • Answers where things run** and what failure domains* or environments exist*.

  • Context

    • Complements logical C4/Diagram/2 - Containers—same software boxes, now placed on real(istic) hardware and cloud shapes (see C4/Diagram).

  • Key principles

    • Environment truth — Distinguish prod vs non-prod when differences matter for risk discussion.
    • Infra vocabulary — Use terms your SRE / platform team recognises (VPCs, subnets, k8s namespaces, …) at the right altitude.

  • Mechanism

    • Often generated from IaC (Terraform, CDK) or cloud console exports for accuracy.

  • Examples

    • Multi-region active-active services; hybrid on-prem + cloud egress paths; zero-trust segmentation between tiers.

  • Misconceptions

    • “Deployment = container diagram” — Different questions—logical vs physical / cloud mapping.
    • “Must show every VM” — Usually too low; abstract to meaningful deployment units unless troubleshooting.