[SLING-3434] Make intra-cluster discovery-heartbeats independent from machine clock differences

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Incomplete
• Affects Version/s: Discovery Impl 1.0.2
• Component/s: Extensions
• Assignee: Stefan Egli
• Reporter: Stefan Egli
• Created: 05/Mar/14 13:37
• Updated: 12/Nov/15 11:23
• Resolved: 29/Jan/15 17:12

Description

SLING-2967 fixed an issue where topology connectors were dependent on having machine clocks in sync - so inter-cluster we're no longer dependent on NTP-synching.

Inside a cluster though, this problem is still there. Since heartbeats are written as absolute time - based on the originator's machine clock - it still only works fine the whole cluster is NTP-synched.

In general I think this is not a problem as it is best-practice to make sure machines have NTP set up.

Nevertheless, it would help if discovery.impl could become independent from this.

Also, if clocks are off by too much, pseudo-network-partitions can occur, with the result of having multiple leaders in a cluster (also see SLING-3432)

Issue Links

• breaks: SLING-5027 vote loop until vote is promoted
• is related to: SLING-2967 Make topology connectors independent from machine clocks differences
• is related to: SLING-3432 pseudo network partition causes job deserialization issue in a cluster (when reading while job is being reassigned)