Added syncer for steal time metric and started implementing feature extractor for it

Author: SoWieMarkus

helm/bundles/cortex-nova/values.yaml

@@ -113,6 +113,9 @@ cortex-core:
                 (sum by (node) (node_memory_MemTotal_bytes) / count by (node) (node_memory_MemTotal_bytes))
               )) * 100
             type: node_exporter_metric
+          - alias: kvm_libvirt_domain_steal_time
+            query: rate(kvm_libvirt_domain_steal_time[1m])
+            type: kvm_cpu_steal_time_metric
 
       openstack:
         nova:
@@ -195,6 +198,16 @@ cortex-core:
                   - alias: vrops_hostsystem_cpu_contention_short_term_percentage
 
         # KVM-specific extractors.
+        - name: libvirt_domain_cpu_steal_time_extractor
+          dependencies:
+            sync:
+              prometheus:
+                metrics:
+                  - alias: kvm_libvirt_domain_steal_time
+              openstack:
+                nova:
+                  types:
+                    - servers
         - name: node_exporter_host_cpu_usage_extractor
           dependencies:
             sync:

helm/library/cortex-core/templates/alerts.yaml

@@ -31,6 +31,7 @@ var SupportedExtractors = []plugins.FeatureExtractor{
 	// KVM-specific extractors
 	&kvm.NodeExporterHostCPUUsageExtractor{},
 	&kvm.NodeExporterHostMemoryActiveExtractor{},
+	&kvm.LibvirtDomainCPUStealTimeExtractor{},
 	// NetApp-specific extractors
 	&netapp.StoragePoolCPUUsageExtractor{},
 	// Shared extractors

internal/extractor/pipeline.go

@@ -0,0 +1,56 @@
+// Copyright 2025 SAP SE
+// SPDX-License-Identifier: Apache-2.0
+
+package kvm
+
+import (
+	_ "embed"
+
+	"github.com/cobaltcore-dev/cortex/internal/db"
+	"github.com/cobaltcore-dev/cortex/internal/extractor/plugins"
+	"github.com/cobaltcore-dev/cortex/internal/sync/prometheus"
+)
+
+// Feature that maps CPU steal time of kvm hosts.
+type LibvirtDomainCPUStealTime struct {
+	Instance string
+}
+
+// Table under which the feature is stored.
+func (LibvirtDomainCPUStealTime) TableName() string {
+	return "feature_libvirt_domain_cpu_steal_time"
+}
+
+// Indexes for the feature.
+func (LibvirtDomainCPUStealTime) Indexes() []db.Index {
+	return nil
+}
+
+// Extractor that extracts CPU steal time
+type LibvirtDomainCPUStealTimeExtractor struct {
+	// Common base for all extractors that provides standard functionality.
+	plugins.BaseExtractor[
+		struct{},                  // No options passed through yaml config
+		LibvirtDomainCPUStealTime, // Feature model
+	]
+}
+
+// Name of this feature extractor that is used in the yaml config, for logging etc.
+func (*LibvirtDomainCPUStealTimeExtractor) GetName() string {
+	return "libvirt_domain_cpu_steal_time_extractor"
+}
+
+// Get message topics that trigger a re-execution of this extractor.
+func (LibvirtDomainCPUStealTimeExtractor) Triggers() []string {
+	return []string{
+		prometheus.TriggerMetricAliasSynced("kvm_libvirt_domain_steal_time"),
+	}
+}
+
+//go:embed cpu_steal_time.sql
+var cpuStealTimeSQL string
+
+// Extract CPU steal time of kvm hosts.
+func (e *LibvirtDomainCPUStealTimeExtractor) Extract() ([]plugins.Feature, error) {
+	return e.ExtractSQL(cpuStealTimeSQL)
+}

internal/extractor/plugins/kvm/cpu_steal_time.go

@@ -0,0 +1,7 @@
+SELECT * FROM (
+    SELECT *,
+           ROW_NUMBER() OVER (PARTITION BY os.id ORDER BY kvm.timestamp DESC) as rn
+    FROM kvm_cpu_steal_time_metrics kvm
+    LEFT JOIN openstack_servers os ON os.os_ext_srv_attr_instance_name = kvm.domain
+) ranked
+WHERE rn = 1 AND os.id IS NOT NULL;

internal/extractor/plugins/kvm/cpu_steal_time.sql

@@ -33,6 +33,7 @@ var SupportedSyncers = map[string]syncerFunc{
 	"netapp_aggregate_labels_metric":        newSyncerOfType[NetAppAggregateLabelsMetric],
 	"netapp_node_metric":                    newSyncerOfType[NetAppNodeMetric],
 	"netapp_volume_aggregate_labels_metric": newSyncerOfType[NetAppVolumeAggrLabelsMetric],
+	"kvm_cpu_steal_time_metric":             newSyncerOfType[KVMCPUStealTimeMetric],
 }
 
 // Syncer that syncs all configured metrics.

internal/sync/prometheus/sync.go

@@ -266,3 +266,29 @@ func (m NetAppVolumeAggrLabelsMetric) With(n string, t time.Time, v float64) Pro
 	m.Value = v
 	return m
 }
+
+type KVMCPUStealTimeMetric struct {
+	// The name of the metric.
+	Name     string `db:"name"`
+	Instance string `json:"instance" db:"instance"`
+	Domain   string `json:"domain" db:"domain"`
+	Node     string `json:"node" db:"node"`
+	// Timestamp of the metric value.
+	Timestamp time.Time `json:"timestamp" db:"timestamp"`
+	// The value of the metric (usually 1 for label metrics).
+	Value float64 `json:"value" db:"value"`
+}
+
+func (m KVMCPUStealTimeMetric) TableName() string {
+	return "kvm_cpu_steal_time_metrics"
+}
+func (m KVMCPUStealTimeMetric) Indexes() []db.Index     { return nil }
+func (m KVMCPUStealTimeMetric) GetName() string         { return m.Name }
+func (m KVMCPUStealTimeMetric) GetTimestamp() time.Time { return m.Timestamp }
+func (m KVMCPUStealTimeMetric) GetValue() float64       { return m.Value }
+func (m KVMCPUStealTimeMetric) With(n string, t time.Time, v float64) PrometheusMetric {
+	m.Name = n
+	m.Timestamp = t
+	m.Value = v
+	return m
+}