Briefly, this error occurs when Elasticsearch tries to allocate shards but can’t find any node in the largest zone. This could be due to insufficient resources, misconfiguration, or network issues. To resolve this, you can add more nodes to the zone, check your shard allocation settings, or troubleshoot network connectivity. Also, ensure that your cluster is properly balanced and that there are no overloaded nodes that could be causing the issue.
This guide will help you check for common problems that cause the log ” no assignments remain in the largest zone ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin.
Log Context
Log “no assignments remain in the largest zone” classname is AllocationReducer.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :
.filter(e -> nodeIdsByZone.get(largestZone).contains(e.getKey()))
.sorted(Map.Entry.comparingByValue())
.toList();
if (largestZoneAssignmentsInAscendingOrder.isEmpty()) {
logger.warn("no assignments remain in the largest zone");
throw new IllegalStateException("no assignments remain in the largest zone");
}
Map.Entry smallestAssignmentInLargestZone = largestZoneAssignmentsInAscendingOrder.get(0);
if (canAssignmentBeRemovedEntirely(
