Tag

leases

16 articles

Jul 29, 2026 Leader Leases and Fencing Tokens in Failover Why a demoted leader can still issue writes, how time-based leases bound that window, and why fencing tokens rather than timeouts are what actually protects shared storage. distributed systems
May 4, 2026 Lease Safety Margins Under Clock Drift The arithmetic that keeps a lease from being granted twice: how offset error, drift rate, and timer resolution set the gap between the client deadline and the server reassignment. distributed systems
Jan 12, 2026 Draining a Worker Pool Without Losing or Doubling the Work The shutdown sequence for a job worker: stop claiming, cancel at a deadline, release leases instead of waiting for expiry, and keep heartbeats alive until the handlers stop. backend systems
Nov 10, 2025 Grace Periods and Reclaiming State After a Server Restart A server that keeps open state loses it on reboot, while its clients still believe they hold locks and delegations. The grace period is the interval in which only reclaims are accepted, and its length is a bet on how fast clients notice. filesystems
Nov 4, 2025 Fencing Tokens and the Arithmetic of Lease Expiry Why a promoted primary must wait out the old primary lease before accepting writes, how fencing tokens stop a stalled writer, and where the wait comes from. cloud infrastructure
Aug 26, 2025 Conditional Writes: Building a Lock Out of Single-Key Compare-and-Set A precondition on an object write gives one writer a win and the rest a 412. How to use that primitive for leases, exactly-once publication, and safe fan-out. cloud infrastructure
Jun 11, 2025 The Lease as a Time-Bounded Grant: Why Expiry Needs No Message How a lease replaces an explicit release with a deadline, why the holder must stop before the server reassigns, and what the gap between the two clocks costs. distributed systems
May 26, 2025 Delegations, Callback Channels, and Recall A server can hand a client authority over a file so the client stops asking, but it must be able to take that authority back. The mechanism is a lease with a reverse direction, and its hard part is the recall path. filesystems
Jan 28, 2025 Fencing Tokens: Why a Lock Is Advisory Until the Resource Checks It How a monotonic token attached to a grant lets the protected resource reject a stale holder, and why no amount of clock discipline makes the check unnecessary. distributed systems
Dec 24, 2024 Read Index and Leader Leases: Serving Reads Without a Log Entry Why a committed write is not yet a readable write, how a quorum heartbeat round establishes read freshness, and what a lease assumes about clocks. distributed systems
Nov 18, 2024 Leader Election, Leases, and What Quorum Protects Against Why a control plane needs a single active writer, how lease-based election bounds the overlap window, and where the underlying consensus store changes the guarantee. virtualization
May 15, 2024 Byte-Range Locks and What Happens When a Client Dies The server owns the lock, the client owns the local enforcement, and neither can see the other side. That split explains lock leasing, the difference between local and NLM locking, and why a dead client blocks a range until the server notices. filesystems
May 14, 2024 Worker Leases, Heartbeats, and the Zombie Task Problem How a lease turns liveness into a deadline, why an expired lease cannot prove a task stopped, and how fencing tokens contain the overlap. data engineering
Mar 12, 2024 Visibility Timeouts and Lease Heartbeats in Job Claims Why a claimed job stays hidden from other workers only until a deadline, how heartbeats extend that deadline safely, and what happens when the worker is alive but cannot renew. backend systems
Apr 14, 2022 Fencing Tokens and the Worker That Did Not Notice It Was Replaced How a monotonic lease epoch stored beside the protected data stops a stale worker from committing, why a timestamp cannot serve as the token, and what the guarantee excludes. backend systems
Mar 15, 2022 Heartbeats, Leases, and the Timeout That Declares a Node Dead Why node liveness is a leased lease with a bounded renewal, how the kubelet's lease write differs from its status report, and what a false positive costs when the network partitions. virtualization