Use one authoritative clock boundary for lease decisions
Two instances disagree about lease expiry because their local clocks differ by several seconds.
- Focused work estimate
- 2h 30m + prerequisites
- Priority in the scenario
- Medium
- Engineering practice
- Clock semantics · Distributed assumptions
Estimated field mix
- Distributed systems100%
Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence.
Review it, then add it to your workspace.
The board opens an editable draft; nothing is saved until you confirm it. Sign-in and workspace permissions apply, and Demo boards remain ephemeral.
Project context
A fictional document service runs periodic retention planning on multiple application instances. Paused instances resume after lease expiry and can overlap newer schedulers.
Setup prerequisites
- Create a synthetic maintenance queue and two independent scheduler clients.
- Use fake time where possible and no destructive real retention actions.
Preceding work
Complete these dependencies, or supply their agreed outputs before taking this ticket.
Acceptance criteria
- Define the clock used for acquisition and expiry checks.
- Keep client clock readings out of authority decisions.
- Document pause and network-delay assumptions.
Implementation constraints
- Prefer database time within the transaction for this local PostgreSQL exercise.
Verification to include
- Skew client clocks and obtain the same database lease decision.
- Reach exact expiry and verify the documented eligibility boundary.
Deliverables
- Clock-bound lease queries and skew test
Rollout and recovery
Canary lease reads under controlled skew; stop acquisition if authoritative time is unavailable.
Value of the work
For the engineer: Practice lease assumptions, fencing and stale-owner rejection.
For the team: Review safe coordination that remains explainable under pauses and recovery.
Evidence boundaries
Outcome Evidence: Tests, patches, and runbooks are requested deliverables. They become Outcome Evidence only through a qualified Mission and immutable Evidence IDs.
Ownership Evidence: Independent adaptation must be observed under a declared verification policy and cite immutable Evidence IDs. Completing a planning ticket establishes no Ownership Evidence.