recall

← recall

lease pattern

A time-bounded exclusive grant. Holder gets exclusive access until the lease expires; if they want to keep it, they renew. Combines locking with automatic recovery — if the holder dies, the lease times out and someone else takes over.

A time-bounded exclusive grant. Holder gets exclusive access until the lease expires; if they want to keep it, they renew. Combines locking with automatic recovery — if the holder dies, the lease times out and someone else takes over.

symptoms

  • need exclusive access but worry about a crashed holder blocking forever
  • single-leader systems where the leader might disappear silently

causes

  • traditional locks don't auto-release on holder death
  • need a liveness signal built into the locking primitive

fixes

  • TTL-bound lock + heartbeat to renew
  • fencing token on every lease for safety against stale holders
  • lease store backed by consensus (etcd, ZooKeeper)

you might say

  • take a lease on it
  • renew the lease
  • lease expired

related

topics: distributed-systems, consensus

references: