[SOLR-8561] Add fallback to ZkController.getLeaderProps for a mixed 5.4-pre-5.4 deployments

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 5.4.1, 5.5
• Component/s: SolrCloud
• Assignee: Shai Erera
• Reporter: Shai Erera
• Created: 18/Jan/16 04:19
• Updated: 21/Nov/19 00:42
• Resolved: 18/Jan/16 10:01

Description

See last comments in SOLR-7844. The latter changed the structure of the leader path in ZK such that upgrading from pre-5.4 to 5.4 is impossible, unless all nodes are taken down. This issue adds a fallback logic to look for the leader properties on the old ZK node, as discussed.

Issue Links

• duplicates: SOLR-8531 ZK leader path changed in 5.4
• is related to: SOLR-8843 Missing fallback for NoChildrenForEphemeralsException on ZkController.getLeaderPropsWithFallback for rolling upgrade