[ZOOKEEPER-2169] Enable creation of nodes with TTLs

• Type: New Feature
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.6.0
• Fix Version/s: 3.5.5
• Component/s: c client, java client, jute, server
• Labels: ttl_nodes
• Assignee: Jordan Zimmerman
• Reporter: Camille Fournier
• Created: 16/Apr/15 20:21
• Updated: 28/Apr/23 02:46
• Resolved: 09/Oct/16 18:36

Description

As a user, I would like to be able to create a node that is NOT tied to a session but that WILL expire automatically if action is not taken by some client within a time window.

I propose this to enable clients interacting with ZK via http or other "thin clients" to create ephemeral-like nodes.

Some ideas for the design, up for discussion:

The node should support all normal ZK node operations including ACLs, sequential key generation, etc, however, it should not support the ephemeral flag. The node will be created with a TTL that is updated via a refresh operation.

The ZK quorum will watch this node similarly to the way that it watches for session liveness; if the node is not refreshed within the TTL, it will expire.

QUESTIONS:

1) Should we let the refresh operation set the TTL to a different base value?
2) If so, should the setting of the TTL to a new base value cause a watch to fire?
3) Do we want to allow these nodes to have children or prevent this similar to ephemeral nodes?

Issue Links

• is duplicated by: ZOOKEEPER-1925 Time to Live or auto expiration of zookeeper node
• is related to: ZOOKEEPER-2901 Session ID that is negative causes mis-calculation of Ephemeral Type
• is related to: ZOOKEEPER-4690 Expose TTL ZNode information
• supercedes: ZOOKEEPER-1925 Time to Live or auto expiration of zookeeper node
• links to: GitHub Pull Request #82

Sub-Tasks

• Create CLI option for TTL ephemerals: Resolved
• Add TTL Node APIs to C client: Closed