Glossary · System coordination, integration and orchestration
Lease (distributed systems)
Also known as: time-limited lock, lease-based lock
German: Lease
In distributed systems, a lease is a time-limited right granted to a node, for example to hold a lock, act as leader or cache data, which expires automatically unless it is renewed before a defined deadline.
- System integration
In one sentence
A lease is a time-limited right, such as a lock or leadership, that expires automatically unless the holder renews it in time.
Example
An AGV receives a 30-second lease on a narrow aisle segment from the fleet manager and must renew it while driving; if the AGV fails, the segment is released after the lease expires.
How it applies
- Engineering: Leases solve the problem of a lock holder that fails and never releases the lock: after expiry, the resource becomes available again. The lease time trades faster recovery against more renewal traffic.
- Timing: Lease correctness depends on clocks advancing at similar rates on holder and grantor. The holder should stop using the resource somewhat before its lease expires.
- Documentation: Document lease durations, renewal intervals and the behavior on expiry in the system design. For physical resources such as aisle segments, operators need to know how long a failed vehicle blocks a resource.
Lease vs. lock
A conventional lock is held until explicitly released. A lease is released automatically after a set time, which makes it safer when holders can fail, at the cost of periodic renewal.