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ADR-0002: Minimal expandable bootstrap sizing

Date: 2026-08-29 Status: Accepted, pending implementation

Context

The RKE2 foundation needs production-shaped HA without reserving the larger resources proposed in early planning documents before actual utilization is known.

Decision

  • Start with three control planes at 4 vCPU, 8 GiB RAM, and 50 GiB local disk.
  • Start with three platform workers at 4 vCPU, 8 GiB RAM, and 60 GiB shared disk.
  • Start the external operations VM at 2 vCPU, 4 GiB RAM, and 40 GiB shared disk.
  • Start the platform NAT gateway at 2 vCPU, 2 GiB RAM, and 20 GiB shared disk.
  • Disable memory ballooning.
  • Expand CPU, RAM, and disk after observation instead of provisioning the former upper bounds immediately.

Consequences

  • The eight running VMs initially reserve 28 vCPU, 54 GiB RAM, and 390 GiB disk.
  • Three-node etcd quorum is preserved.
  • Platform workers must be expanded before deploying memory-heavy observability or agent services.
  • Resource headroom and placement are rechecked immediately before creation.

Supersedes

This decision replaces the larger initial allocations in earlier bootstrap drafts while retaining their intended node roles and failure-domain separation.