fix(distributor): UserStats returns error when a ring member is LEAVING#7705
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Goutham-Annem wants to merge 1 commit into
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fix(distributor): UserStats returns error when a ring member is LEAVING#7705Goutham-Annem wants to merge 1 commit into
Goutham-Annem wants to merge 1 commit into
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…AVING UserStats queried all ingesters via GetIngestersForMetadata then forced MaxErrors = 0, requiring every ingester to respond successfully. When any ingester was in the LEAVING state (normal during a rolling update) and its RPC failed, UserStats returned an error to the caller. Remove the MaxErrors = 0 override so the ring's own quorum tolerance (RF/2 failures allowed for a Read operation) applies. Partial stats are better than a hard failure on the /api/v1/user_stats page. Closes cortexproject#4936 Signed-off-by: Goutham Annem <gouthemannem@gmail.com>
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Fixes #4936
Proposed Changes
UserStatscalledGetIngestersForMetadata(which usesring.Read, includingLEAVINGinstances) and then explicitly setreplicationSet.MaxErrors = 0, requiring every ingester in the set to respond. During a rolling update or any graceful shutdown, ingesters transition through theLEAVINGstate and may return RPC errors. WithMaxErrors = 0, a single such failure caused the entire/api/v1/user_statsendpoint to return an error.The fix removes the
MaxErrors = 0override and lets the ring's own quorum tolerance apply (RF/2failures are allowed forReadoperations). This matches the behaviour of other metadata endpoints (e.g.LabelValuesForLabelName) that do not overrideMaxErrors.replicationSet.MaxErrors = 0inUserStats; add explanatory commentUserStatsmethod tomockIngesterTestUserStats_ToleratesLeavingIngesterthat confirms the endpoint succeeds with one unhappy ingester out of threeRelease Note