[WIP] Optimize K8s Operator LLAP scaling - #6723
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Pull request overview
This PR updates the Hive Kubernetes Operator autoscaling model and LLAP scaling logic to better distinguish scale-up vs scale-down signals, using additional TezAM/LLAP metrics and a new scaleDownThreshold configuration surfaced through the CRD and Helm chart.
Changes:
- Introduces
scaleDownThresholdtoAutoscalingSpec, wires it through CRD + Helm templates/values, and updates component default specs accordingly. - Extends JMX exporter configuration to expose new LLAP/TezAM metrics used for scaling decisions.
- Refactors LLAP scaling strategy to use TezAM pending-task load + LLAP capacity/load signals, and adds a TezAM-metrics cache accessor to the autoscaler.
Reviewed changes
Copilot reviewed 14 out of 14 changed files in this pull request and generated 3 comments.
Show a summary per file
| File | Description |
|---|---|
| packaging/src/kubernetes/src/java/org/apache/hive/kubernetes/operator/util/HiveConfigBuilder.java | Adjusts Tez config when LLAP autoscaling is enabled (locality delay override behavior). |
| packaging/src/kubernetes/src/java/org/apache/hive/kubernetes/operator/util/ConfigUtils.java | Adds config key constant for LLAP task scheduler locality delay. |
| packaging/src/kubernetes/src/java/org/apache/hive/kubernetes/operator/model/spec/TezAmSpec.java | Updates default AutoscalingSpec construction to include the new field. |
| packaging/src/kubernetes/src/java/org/apache/hive/kubernetes/operator/model/spec/MetastoreSpec.java | Updates default AutoscalingSpec construction to include the new field. |
| packaging/src/kubernetes/src/java/org/apache/hive/kubernetes/operator/model/spec/LlapSpec.java | Updates LLAP + LLAP TezAM autoscaling defaults (including scale-down threshold for LLAP). |
| packaging/src/kubernetes/src/java/org/apache/hive/kubernetes/operator/model/spec/HiveServer2Spec.java | Updates default AutoscalingSpec construction to include the new field. |
| packaging/src/kubernetes/src/java/org/apache/hive/kubernetes/operator/model/spec/AutoscalingSpec.java | Adds scaleDownThreshold with schema/docs and defaulting in the compact constructor. |
| packaging/src/kubernetes/src/java/org/apache/hive/kubernetes/operator/dependent/HiveDependentResource.java | Exposes additional LLAP + TezAM metrics via JMX exporter config for autoscaling. |
| packaging/src/kubernetes/src/java/org/apache/hive/kubernetes/operator/autoscaling/LlapScalingStrategy.java | Reworks LLAP desired-replica computation using Tez pending tasks and LLAP capacity/load signals. |
| packaging/src/kubernetes/src/java/org/apache/hive/kubernetes/operator/autoscaling/HiveClusterAutoscaler.java | Adds cached TezAM-metrics accessor used by LLAP scaling strategy. |
| packaging/src/kubernetes/src/java/org/apache/hive/kubernetes/operator/autoscaling/ComponentAutoscaler.java | Modifies stabilization-window selection logic for LLAP scale-up decisions. |
| packaging/src/kubernetes/helm/hive-operator/values.yaml | Updates LLAP autoscaling defaults (including new scale-down threshold). |
| packaging/src/kubernetes/helm/hive-operator/templates/hivecluster.yaml | Emits scaleDownThreshold into rendered HiveCluster spec. |
| packaging/src/kubernetes/helm/hive-operator/crds/hiveclusters.hive.apache.org-v1.yml | Adds scaleDownThreshold to the CRD schema and updates scaleUpThreshold description text. |
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| if (component.startsWith(ConfigUtils.COMPONENT_LLAP + "-")) { | ||
| // HS2 sessions activation gate scales up the LLAP pods to atleast 1 | ||
| // in presence of sessions. Avoid stabilizedMin in this start-up case. | ||
| target = currentReplicas == 0 ? clamped : scaleUpWindow.stabilizedMin(); |
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| double queued = pm.metrics().getOrDefault(METRIC_QUEUED, 0.0); | ||
| double configured = pm.metrics().getOrDefault(METRIC_CONFIGURED, 0.0); | ||
| double available = pm.metrics().getOrDefault(METRIC_AVAILABLE, 0.0); | ||
| double busy = queued + configured - available; | ||
| totalBusy += busy; | ||
| podCount++; | ||
| totalLLAPCapacity += pm.metrics().getOrDefault(METRIC_MAX_FREE_SLOTS_CONFIGURED, 0.0); | ||
| totalLLAPLoad += queued + configured - available; |
| * desired = ceil(totalClusterLoad / capacityPerDaemon) | ||
| * <p> | ||
| * Activation gate: only scale if HS2 has open sessions (prevents zombie scaling). | ||
| * Activation gate: only scale if HS2 has open sessions & TezAMs are running DAGs (prevents zombie scaling). |
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