fix: Make HttpLoadQueuePeon degrade gracefully instead of throwing on fetch failure - #20128
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waterWang wants to merge 1 commit into
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fix: Make HttpLoadQueuePeon degrade gracefully instead of throwing on fetch failure#20128waterWang wants to merge 1 commit into
waterWang wants to merge 1 commit into
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… fetch failure When a historical server returns a non-200/404 response or is unreachable, fetchSegmentLoadingCapabilities() throws an RE, which propagates through LoadQueueTaskMaster.resetPeonsForNewServers() into PrepareBalancerAndLoadQueues. The top-level DruidCoordinator.DutiesRunnable.run() catches and logs it, but segment management stops entirely for ALL servers — not just the unhealthy one. Fix: degrade gracefully by returning default SegmentLoadingCapabilities derived from the configured batch size, with a warning log. The peon is still created, the server is still managed with conservative defaults, and the rest of the duty group proceeds normally.
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Description
Fixes #19950
When a historical server returns a non-200/404 response or is unreachable
during
fetchSegmentLoadingCapabilities(), theHttpLoadQueuePeonconstructorthrows an
RE. This exception propagates throughLoadQueueTaskMaster.resetPeonsForNewServers()intoPrepareBalancerAndLoadQueues, which is the first duty in theHistoricalManagementDutiesgroup. The top-levelDruidCoordinator.DutiesRunnable.run()catches and logs the exception, butsegment management (loading, balancing, handoffs) stops entirely for all
servers — not just the unhealthy one. Ingestion tasks back up waiting for
handoff.
Changes
fetchSegmentLoadingCapabilities(): Instead of throwingREon non-200/404responses or any
Throwable, return defaultSegmentLoadingCapabilitiesderived from the configured batch size, with a warning log. The peon is still
created, the server is still managed with conservative defaults, and the rest
of the duty group proceeds normally.
capabilities).
Key design decisions
extends this same graceful degradation to non-200 responses and exceptions.
log.makeAlert()is preserved for non-200 responses so operators still getalerted about the unhealthy server.
Coordinator ticking.
Release notes
Fixed a bug where a single unhealthy or unreachable historical server could
stall all segment loading and balancing across the cluster.