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ADR 0021: N+1 capacity indicator: ‘if node A dies, do its apps fit on the others?’

  • Status: Accepted
  • Date: 2026-11-02
  • Ledger id: D-0021
  • Tags: reliability, ha-policy, panel
  • Supersedes: none
  • Superseded by: none
  • Related: none

Context

Users must be told how much space/RAM HA reserves; no self-hosted tool does this well; ideal for an agent to watch.

Decision

N+1 capacity indicator: ‘if node A dies, do its apps fit on the others?’.

Example: ‘yes’ / ‘no, you are missing 6 GB of RAM’.

Consequences

  • This decision is binding for all contributors and agents. Changing it requires a new ADR approved by the maintainer (see ADR 0036).

Generated from decision D-0021 in the project decision ledger. Do not edit by hand; changes go through a new decision.