[SLING-5435] Decouple processes that depend on cluster leader elections from the cluster leader elections.

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Won't Fix
• Component/s: General
• Assignee: Unassigned
• Reporter: Ian Boston
• Created: 15/Jan/16 21:12
• Updated: 26/Sep/19 15:40
• Resolved: 10/Nov/16 11:38

Description

Currently there are many processes in Sling that must complete before a Sling Discovery cluster leader election is declared complete. These processes include things like transferring all Jobs from the old leader to the new leader and waiting for the data to appear visible on the new leader. This introduces an additional overhead to the leader election process which introduces a higher than desirable timeout for elections and heartbeat. This higher than desirable timeout precludes the use of more efficient election and distributed consensus algorithms as implemented in Etcd, Zookeeper or implementations of RAFT.

If the election could be declared complete leaving individual components to manage their own post election operations (ie decoupling those processes from the election), then faster election or alternative Discovery implementations such as the one implemented on etcd could be used.

Issue Links

• relates to: SLING-5423 embedded raft based discovery mechanism
• relates to: SLING-4842 Donation of CoreOS etcd based discovery mechanism