feat: add KVM HANA stacking KPI

helm/bundles/cortex-nova/templates/kpis_kvm.yaml

@@ -26,4 +26,19 @@ spec:
       - name: nova-servers
       - name: nova-flavors
       - name: identity-projects
+      - name: identity-domains
+---
+apiVersion: cortex.cloud/v1alpha1
+kind: KPI
+metadata:
+  name: kvm-hana-stacking
+spec:
+  schedulingDomain: nova
+  impl: kvm_hana_stacking_kpi
+  dependencies:
+    datasources:
+      - name: nova-servers
+      - name: nova-flavors
+      - name: identity-projects
+      - name: identity-domains
 {{- end }}

internal/knowledge/kpis/plugins/infrastructure/kvm_hana_stacking.go

@@ -0,0 +1,117 @@
+// Copyright SAP SE
+// SPDX-License-Identifier: Apache-2.0
+
+package infrastructure
+
+import (
+	"context"
+	"log/slog"
+
+	"github.com/cobaltcore-dev/cortex/internal/knowledge/datasources/plugins/openstack/identity"
+	"github.com/cobaltcore-dev/cortex/internal/knowledge/datasources/plugins/openstack/nova"
+	"github.com/cobaltcore-dev/cortex/internal/knowledge/db"
+	"github.com/cobaltcore-dev/cortex/internal/knowledge/kpis/plugins"
+	"github.com/cobaltcore-dev/cortex/pkg/conf"
+	hv1 "github.com/cobaltcore-dev/openstack-hypervisor-operator/api/v1"
+	"github.com/prometheus/client_golang/prometheus"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+)
+
+const hanaKVMFlavorPattern = "hana_k_%"
+
+type kvmHanaStackingRow struct {
+	ProjectID   string  `db:"project_id"`
+	ProjectName string  `db:"project_name"`
+	DomainID    string  `db:"domain_id"`
+	DomainName  string  `db:"domain_name"`
+	ComputeHost string  `db:"compute_host"`
+	TotalRAMMB  float64 `db:"total_ram_mb"`
+}
+
+type KVMHanaStackingKPI struct {
+	plugins.BaseKPI[struct{}]
+	ramPerProjectAndHost *prometheus.Desc
+}
+
+func (k *KVMHanaStackingKPI) GetName() string {
+	return "kvm_hana_stacking_kpi"
+}
+
+func (k *KVMHanaStackingKPI) Init(dbConn *db.DB, c client.Client, opts conf.RawOpts) error {
+	if err := k.BaseKPI.Init(dbConn, c, opts); err != nil {
+		return err
+	}
+	k.ramPerProjectAndHost = prometheus.NewDesc(
+		"cortex_kvm_hana_stacking_ram_bytes",
+		"Total RAM in bytes used by HANA instances of a project on a KVM hypervisor.",
+		append(kvmHostLabels, "project_id", "project_name", "domain_id", "domain_name"), nil,
+	)
+	return nil
+}
+
+func (k *KVMHanaStackingKPI) Describe(ch chan<- *prometheus.Desc) {
+	ch <- k.ramPerProjectAndHost
+}
+
+func (k *KVMHanaStackingKPI) Collect(ch chan<- prometheus.Metric) {
+	hosts, err := k.getKVMHosts()
+	if err != nil {
+		slog.Error("kvm_hana_stacking: failed to get KVM hosts", "error", err)
+		return
+	}
+
+	rows, err := k.queryHanaStacking()
+	if err != nil {
+		slog.Error("kvm_hana_stacking: failed to query HANA stacking", "error", err)
+		return
+	}
+
+	for _, row := range rows {
+		host, ok := hosts[row.ComputeHost]
+		if !ok {
+			slog.Warn("kvm_hana_stacking: compute host not found", "compute_host", row.ComputeHost)
+			continue
+		}
+		hostLabels := host.getHostLabels()
+		hostLabels = append(hostLabels, row.ProjectID, row.ProjectName, row.DomainID, row.DomainName)
+		ch <- prometheus.MustNewConstMetric(k.ramPerProjectAndHost, prometheus.GaugeValue, row.TotalRAMMB*1024*1024, hostLabels...)
+	}
+}
+
+func (k *KVMHanaStackingKPI) getKVMHosts() (map[string]kvmHost, error) {
+	hvs := &hv1.HypervisorList{}
+	if err := k.Client.List(context.Background(), hvs); err != nil {
+		return nil, err
+	}
+	hosts := make(map[string]kvmHost, len(hvs.Items))
+	for _, hv := range hvs.Items {
+		host := kvmHost{Hypervisor: hv}
+		hosts[host.Name] = host
+	}
+	return hosts, nil
+}
+
+func (k *KVMHanaStackingKPI) queryHanaStacking() ([]kvmHanaStackingRow, error) {
+	query := `
+		SELECT
+			s.tenant_id AS project_id,
+			COALESCE(p.name, '') AS project_name,
+			COALESCE(p.domain_id, '') AS domain_id,
+			COALESCE(d.name, '') AS domain_name,
+			s.os_ext_srv_attr_host AS compute_host,
+			COALESCE(SUM(f.ram), 0) AS total_ram_mb
+		FROM ` + nova.Server{}.TableName() + ` s
+		LEFT JOIN ` + nova.Flavor{}.TableName() + ` f ON s.flavor_name = f.name
+		LEFT JOIN ` + identity.Project{}.TableName() + ` p ON p.id = s.tenant_id
+		LEFT JOIN ` + identity.Domain{}.TableName() + ` d ON d.id = p.domain_id
+		WHERE s.status NOT IN ('DELETED', 'ERROR')
+		  AND s.os_ext_srv_attr_host LIKE '` + kvmComputeHostPattern + `'
+		  AND s.flavor_name LIKE '` + hanaKVMFlavorPattern + `'
+		GROUP BY s.tenant_id, p.name, p.domain_id, d.name, s.os_ext_srv_attr_host
+	`
+	var rows []kvmHanaStackingRow
+	if _, err := k.DB.Select(&rows, query); err != nil {
+		return nil, err
+	}
+	return rows, nil
+}