chore: rename

docs/api/openapi.yml

@@ -2474,6 +2474,65 @@ components:
       - requiredMetricsCheck
       - endTimeBeforeRetention
       type: object
+    InframonitoringtypesNamespaceRecord:
+      properties:
+        failedPodCount:
+          type: integer
+        meta:
+          additionalProperties: {}
+          nullable: true
+          type: object
+        namespaceCPU:
+          format: double
+          type: number
+        namespaceMemory:
+          format: double
+          type: number
+        namespaceName:
+          type: string
+        pendingPodCount:
+          type: integer
+        runningPodCount:
+          type: integer
+        succeededPodCount:
+          type: integer
+        unknownPodCount:
+          type: integer
+      required:
+      - namespaceName
+      - namespaceCPU
+      - namespaceMemory
+      - pendingPodCount
+      - runningPodCount
+      - succeededPodCount
+      - failedPodCount
+      - unknownPodCount
+      - meta
+      type: object
+    InframonitoringtypesNamespaces:
+      properties:
+        endTimeBeforeRetention:
+          type: boolean
+        records:
+          items:
+            $ref: '#/components/schemas/InframonitoringtypesNamespaceRecord'
+          nullable: true
+          type: array
+        requiredMetricsCheck:
+          $ref: '#/components/schemas/InframonitoringtypesRequiredMetricsCheck'
+        total:
+          type: integer
+        type:
+          $ref: '#/components/schemas/InframonitoringtypesResponseType'
+        warning:
+          $ref: '#/components/schemas/Querybuildertypesv5QueryWarnData'
+      required:
+      - type
+      - records
+      - total
+      - requiredMetricsCheck
+      - endTimeBeforeRetention
+      type: object
     InframonitoringtypesNodeCondition:
       enum:
       - ready
@@ -2658,6 +2717,32 @@ components:
       - end
       - limit
       type: object
+    InframonitoringtypesPostableNamespaces:
+      properties:
+        end:
+          format: int64
+          type: integer
+        filter:
+          $ref: '#/components/schemas/Querybuildertypesv5Filter'
+        groupBy:
+          items:
+            $ref: '#/components/schemas/Querybuildertypesv5GroupByKey'
+          nullable: true
+          type: array
+        limit:
+          type: integer
+        offset:
+          type: integer
+        orderBy:
+          $ref: '#/components/schemas/Querybuildertypesv5OrderBy'
+        start:
+          format: int64
+          type: integer
+      required:
+      - start
+      - end
+      - limit
+      type: object
     InframonitoringtypesPostableNodes:
       properties:
         end:
@@ -11152,6 +11237,75 @@ paths:
       summary: List Hosts for Infra Monitoring
       tags:
       - inframonitoring
+  /api/v2/infra_monitoring/namespaces:
+    post:
+      deprecated: false
+      description: 'Returns a paginated list of Kubernetes namespaces with key aggregated
+        pod metrics: CPU usage and memory working set (summed across pods in the group),
+        plus per-group pod counts bucketed by each pod''s latest k8s.pod.phase value
+        in the window (pendingPodCount, runningPodCount, succeededPodCount, failedPodCount,
+        unknownPodCount). Each namespace includes metadata attributes (k8s.namespace.name,
+        k8s.cluster.name). The response type is ''list'' for the default k8s.namespace.name
+        grouping or ''grouped_list'' for custom groupBy keys; in both modes every
+        row aggregates pods in the group. Supports filtering via a filter expression,
+        custom groupBy, ordering by cpu / memory, and pagination via offset/limit.
+        Also reports missing required metrics and whether the requested time range
+        falls before the data retention boundary. Numeric metric fields (namespaceCPU,
+        namespaceMemory) return -1 as a sentinel when no data is available for that
+        field.'
+      operationId: ListNamespaces
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/InframonitoringtypesPostableNamespaces'
+      responses:
+        "200":
+          content:
+            application/json:
+              schema:
+                properties:
+                  data:
+                    $ref: '#/components/schemas/InframonitoringtypesNamespaces'
+                  status:
+                    type: string
+                required:
+                - status
+                - data
+                type: object
+          description: OK
+        "400":
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RenderErrorResponse'
+          description: Bad Request
+        "401":
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RenderErrorResponse'
+          description: Unauthorized
+        "403":
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RenderErrorResponse'
+          description: Forbidden
+        "500":
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RenderErrorResponse'
+          description: Internal Server Error
+      security:
+      - api_key:
+        - VIEWER
+      - tokenizer:
+        - VIEWER
+      summary: List Namespaces for Infra Monitoring
+      tags:
+      - inframonitoring
   /api/v2/infra_monitoring/nodes:
     post:
       deprecated: false

frontend/src/api/generated/services/inframonitoring/index.ts

@@ -13,9 +13,11 @@ import type {
 
 import type {
 	InframonitoringtypesPostableHostsDTO,
+	InframonitoringtypesPostableNamespacesDTO,
 	InframonitoringtypesPostableNodesDTO,
 	InframonitoringtypesPostablePodsDTO,
 	ListHosts200,
+	ListNamespaces200,
 	ListNodes200,
 	ListPods200,
 	RenderErrorResponseDTO,
@@ -108,6 +110,90 @@ export const useListHosts = <
 
 	return useMutation(mutationOptions);
 };
+/**
+ * Returns a paginated list of Kubernetes namespaces with key aggregated pod metrics: CPU usage and memory working set (summed across pods in the group), plus per-group pod counts bucketed by each pod's latest k8s.pod.phase value in the window (pendingPodCount, runningPodCount, succeededPodCount, failedPodCount, unknownPodCount). Each namespace includes metadata attributes (k8s.namespace.name, k8s.cluster.name). The response type is 'list' for the default k8s.namespace.name grouping or 'grouped_list' for custom groupBy keys; in both modes every row aggregates pods in the group. Supports filtering via a filter expression, custom groupBy, ordering by cpu / memory, and pagination via offset/limit. Also reports missing required metrics and whether the requested time range falls before the data retention boundary. Numeric metric fields (namespaceCPU, namespaceMemory) return -1 as a sentinel when no data is available for that field.
+ * @summary List Namespaces for Infra Monitoring
+ */
+export const listNamespaces = (
+	inframonitoringtypesPostableNamespacesDTO: BodyType<InframonitoringtypesPostableNamespacesDTO>,
+	signal?: AbortSignal,
+) => {
+	return GeneratedAPIInstance<ListNamespaces200>({
+		url: `/api/v2/infra_monitoring/namespaces`,
+		method: 'POST',
+		headers: { 'Content-Type': 'application/json' },
+		data: inframonitoringtypesPostableNamespacesDTO,
+		signal,
+	});
+};
+
+export const getListNamespacesMutationOptions = <
+	TError = ErrorType<RenderErrorResponseDTO>,
+	TContext = unknown,
+>(options?: {
+	mutation?: UseMutationOptions<
+		Awaited<ReturnType<typeof listNamespaces>>,
+		TError,
+		{ data: BodyType<InframonitoringtypesPostableNamespacesDTO> },
+		TContext
+	>;
+}): UseMutationOptions<
+	Awaited<ReturnType<typeof listNamespaces>>,
+	TError,
+	{ data: BodyType<InframonitoringtypesPostableNamespacesDTO> },
+	TContext
+> => {
+	const mutationKey = ['listNamespaces'];
+	const { mutation: mutationOptions } = options
+		? options.mutation &&
+			'mutationKey' in options.mutation &&
+			options.mutation.mutationKey
+			? options
+			: { ...options, mutation: { ...options.mutation, mutationKey } }
+		: { mutation: { mutationKey } };
+
+	const mutationFn: MutationFunction<
+		Awaited<ReturnType<typeof listNamespaces>>,
+		{ data: BodyType<InframonitoringtypesPostableNamespacesDTO> }
+	> = (props) => {
+		const { data } = props ?? {};
+
+		return listNamespaces(data);
+	};
+
+	return { mutationFn, ...mutationOptions };
+};
+
+export type ListNamespacesMutationResult = NonNullable<
+	Awaited<ReturnType<typeof listNamespaces>>
+>;
+export type ListNamespacesMutationBody =
+	BodyType<InframonitoringtypesPostableNamespacesDTO>;
+export type ListNamespacesMutationError = ErrorType<RenderErrorResponseDTO>;
+
+/**
+ * @summary List Namespaces for Infra Monitoring
+ */
+export const useListNamespaces = <
+	TError = ErrorType<RenderErrorResponseDTO>,
+	TContext = unknown,
+>(options?: {
+	mutation?: UseMutationOptions<
+		Awaited<ReturnType<typeof listNamespaces>>,
+		TError,
+		{ data: BodyType<InframonitoringtypesPostableNamespacesDTO> },
+		TContext
+	>;
+}): UseMutationResult<
+	Awaited<ReturnType<typeof listNamespaces>>,
+	TError,
+	{ data: BodyType<InframonitoringtypesPostableNamespacesDTO> },
+	TContext
+> => {
+	const mutationOptions = getListNamespacesMutationOptions(options);
+
+	return useMutation(mutationOptions);
+};
 /**
  * Returns a paginated list of Kubernetes nodes with key metrics: CPU usage, CPU allocatable, memory working set, memory allocatable, and per-group readyNodesCount / notReadyNodesCount derived from each node's latest k8s.node.condition_ready value in the window. Each node includes metadata attributes (k8s.node.uid, k8s.cluster.name). The response type is 'list' for the default k8s.node.name grouping (each row is one node with its current condition string: ready / not_ready / '') or 'grouped_list' for custom groupBy keys (each row aggregates nodes in the group with readyNodesCount and notReadyNodesCount; condition stays empty). Supports filtering via a filter expression, custom groupBy, ordering by cpu / cpu_allocatable / memory / memory_allocatable, and pagination via offset/limit. Also reports missing required metrics and whether the requested time range falls before the data retention boundary. Numeric metric fields (nodeCPU, nodeCPUAllocatable, nodeMemory, nodeMemoryAllocatable) return -1 as a sentinel when no data is available for that field.
  * @summary List Nodes for Infra Monitoring

frontend/src/api/generated/services/sigNoz.schemas.ts

@@ -3243,6 +3243,74 @@ export interface InframonitoringtypesHostsDTO {
 	warning?: Querybuildertypesv5QueryWarnDataDTO;
 }
 
+/**
+ * @nullable
+ */
+export type InframonitoringtypesNamespaceRecordDTOMeta = {
+	[key: string]: unknown;
+} | null;
+
+export interface InframonitoringtypesNamespaceRecordDTO {
+	/**
+	 * @type integer
+	 */
+	failedPodCount: number;
+	/**
+	 * @type object
+	 * @nullable true
+	 */
+	meta: InframonitoringtypesNamespaceRecordDTOMeta;
+	/**
+	 * @type number
+	 * @format double
+	 */
+	namespaceCPU: number;
+	/**
+	 * @type number
+	 * @format double
+	 */
+	namespaceMemory: number;
+	/**
+	 * @type string
+	 */
+	namespaceName: string;
+	/**
+	 * @type integer
+	 */
+	pendingPodCount: number;
+	/**
+	 * @type integer
+	 */
+	runningPodCount: number;
+	/**
+	 * @type integer
+	 */
+	succeededPodCount: number;
+	/**
+	 * @type integer
+	 */
+	unknownPodCount: number;
+}
+
+export interface InframonitoringtypesNamespacesDTO {
+	/**
+	 * @type boolean
+	 */
+	endTimeBeforeRetention: boolean;
+	/**
+	 * @type array
+	 * @nullable true
+	 */
+	records: InframonitoringtypesNamespaceRecordDTO[] | null;
+	requiredMetricsCheck: InframonitoringtypesRequiredMetricsCheckDTO;
+	/**
+	 * @type integer
+	 */
+	total: number;
+	type: InframonitoringtypesResponseTypeDTO;
+	warning?: Querybuildertypesv5QueryWarnDataDTO;
+}
+
 export enum InframonitoringtypesNodeConditionDTO {
 	ready = 'ready',
 	not_ready = 'not_ready',
@@ -3445,6 +3513,34 @@ export interface InframonitoringtypesPostableHostsDTO {
 	start: number;
 }
 
+export interface InframonitoringtypesPostableNamespacesDTO {
+	/**
+	 * @type integer
+	 * @format int64
+	 */
+	end: number;
+	filter?: Querybuildertypesv5FilterDTO;
+	/**
+	 * @type array
+	 * @nullable true
+	 */
+	groupBy?: Querybuildertypesv5GroupByKeyDTO[] | null;
+	/**
+	 * @type integer
+	 */
+	limit: number;
+	/**
+	 * @type integer
+	 */
+	offset?: number;
+	orderBy?: Querybuildertypesv5OrderByDTO;
+	/**
+	 * @type integer
+	 * @format int64
+	 */
+	start: number;
+}
+
 export interface InframonitoringtypesPostableNodesDTO {
 	/**
 	 * @type integer
@@ -7580,6 +7676,14 @@ export type ListHosts200 = {
 	status: string;
 };
 
+export type ListNamespaces200 = {
+	data: InframonitoringtypesNamespacesDTO;
+	/**
+	 * @type string
+	 */
+	status: string;
+};
+
 export type ListNodes200 = {
 	data: InframonitoringtypesNodesDTO;
 	/**

pkg/apiserver/signozapiserver/inframonitoring.go

@@ -67,5 +67,24 @@ func (provider *provider) addInfraMonitoringRoutes(router *mux.Router) error {
 		return err
 	}
 
+	if err := router.Handle("/api/v2/infra_monitoring/namespaces", handler.New(
+		provider.authZ.ViewAccess(provider.infraMonitoringHandler.ListNamespaces),
+		handler.OpenAPIDef{
+			ID:                  "ListNamespaces",
+			Tags:                []string{"inframonitoring"},
+			Summary:             "List Namespaces for Infra Monitoring",
+			Description:         "Returns a paginated list of Kubernetes namespaces with key aggregated pod metrics: CPU usage and memory working set (summed across pods in the group), plus per-group pod counts bucketed by each pod's latest k8s.pod.phase value in the window (pendingPodCount, runningPodCount, succeededPodCount, failedPodCount, unknownPodCount). Each namespace includes metadata attributes (k8s.namespace.name, k8s.cluster.name). The response type is 'list' for the default k8s.namespace.name grouping or 'grouped_list' for custom groupBy keys; in both modes every row aggregates pods in the group. Supports filtering via a filter expression, custom groupBy, ordering by cpu / memory, and pagination via offset/limit. Also reports missing required metrics and whether the requested time range falls before the data retention boundary. Numeric metric fields (namespaceCPU, namespaceMemory) return -1 as a sentinel when no data is available for that field.",
+			Request:             new(inframonitoringtypes.PostableNamespaces),
+			RequestContentType:  "application/json",
+			Response:            new(inframonitoringtypes.Namespaces),
+			ResponseContentType: "application/json",
+			SuccessStatusCode:   http.StatusOK,
+			ErrorStatusCodes:    []int{http.StatusBadRequest, http.StatusUnauthorized},
+			Deprecated:          false,
+			SecuritySchemes:     newSecuritySchemes(types.RoleViewer),
+		})).Methods(http.MethodPost).GetError(); err != nil {
+		return err
+	}
+
 	return nil
 }

pkg/modules/inframonitoring/implinframonitoring/handler.go

@@ -93,3 +93,27 @@ func (h *handler) ListNodes(rw http.ResponseWriter, req *http.Request) {
 
 	render.Success(rw, http.StatusOK, result)
 }
+
+func (h *handler) ListNamespaces(rw http.ResponseWriter, req *http.Request) {
+	claims, err := authtypes.ClaimsFromContext(req.Context())
+	if err != nil {
+		render.Error(rw, err)
+		return
+	}
+
+	orgID := valuer.MustNewUUID(claims.OrgID)
+
+	var parsedReq inframonitoringtypes.PostableNamespaces
+	if err := binding.JSON.BindBody(req.Body, &parsedReq); err != nil {
+		render.Error(rw, err)
+		return
+	}
+
+	result, err := h.module.ListNamespaces(req.Context(), orgID, &parsedReq)
+	if err != nil {
+		render.Error(rw, err)
+		return
+	}
+
+	render.Success(rw, http.StatusOK, result)
+}

pkg/modules/inframonitoring/implinframonitoring/module.go

@@ -325,3 +325,92 @@ func (m *module) ListNodes(ctx context.Context, orgID valuer.UUID, req *inframon
 
 	return resp, nil
 }
+
+func (m *module) ListNamespaces(ctx context.Context, orgID valuer.UUID, req *inframonitoringtypes.PostableNamespaces) (*inframonitoringtypes.Namespaces, error) {
+	if err := req.Validate(); err != nil {
+		return nil, err
+	}
+
+	resp := &inframonitoringtypes.Namespaces{}
+
+	if req.OrderBy == nil {
+		req.OrderBy = &qbtypes.OrderBy{
+			Key: qbtypes.OrderByKey{
+				TelemetryFieldKey: telemetrytypes.TelemetryFieldKey{
+					Name: inframonitoringtypes.NamespacesOrderByCPU,
+				},
+			},
+			Direction: qbtypes.OrderDirectionDesc,
+		}
+	}
+
+	if len(req.GroupBy) == 0 {
+		req.GroupBy = []qbtypes.GroupByKey{namespaceNameGroupByKey}
+		resp.Type = inframonitoringtypes.ResponseTypeList
+	} else {
+		resp.Type = inframonitoringtypes.ResponseTypeGroupedList
+	}
+
+	missingMetrics, minFirstReportedUnixMilli, err := m.getMetricsExistenceAndEarliestTime(ctx, namespacesTableMetricNamesList)
+	if err != nil {
+		return nil, err
+	}
+	if len(missingMetrics) > 0 {
+		resp.RequiredMetricsCheck = inframonitoringtypes.RequiredMetricsCheck{MissingMetrics: missingMetrics}
+		resp.Records = []inframonitoringtypes.NamespaceRecord{}
+		resp.Total = 0
+		return resp, nil
+	}
+	if req.End < int64(minFirstReportedUnixMilli) {
+		resp.EndTimeBeforeRetention = true
+		resp.Records = []inframonitoringtypes.NamespaceRecord{}
+		resp.Total = 0
+		return resp, nil
+	}
+	resp.RequiredMetricsCheck = inframonitoringtypes.RequiredMetricsCheck{MissingMetrics: []string{}}
+
+	metadataMap, err := m.getNamespacesTableMetadata(ctx, req)
+	if err != nil {
+		return nil, err
+	}
+
+	resp.Total = len(metadataMap)
+
+	pageGroups, err := m.getTopNamespaceGroups(ctx, orgID, req, metadataMap)
+	if err != nil {
+		return nil, err
+	}
+
+	if len(pageGroups) == 0 {
+		resp.Records = []inframonitoringtypes.NamespaceRecord{}
+		return resp, nil
+	}
+
+	filterExpr := ""
+	if req.Filter != nil {
+		filterExpr = req.Filter.Expression
+	}
+
+	fullQueryReq := buildFullQueryRequest(req.Start, req.End, filterExpr, req.GroupBy, pageGroups, m.newNamespacesTableListQuery())
+	queryResp, err := m.querier.QueryRange(ctx, orgID, fullQueryReq)
+	if err != nil {
+		return nil, err
+	}
+
+	// Reuse the pods phase-counts CTE function via a temp struct — it reads only
+	// Start/End/Filter/GroupBy from PostablePods.
+	phaseCounts, err := m.getPerGroupPodPhaseCounts(ctx, &inframonitoringtypes.PostablePods{
+		Start:   req.Start,
+		End:     req.End,
+		Filter:  req.Filter,
+		GroupBy: req.GroupBy,
+	}, pageGroups)
+	if err != nil {
+		return nil, err
+	}
+
+	resp.Records = buildNamespaceRecords(queryResp, pageGroups, req.GroupBy, metadataMap, phaseCounts)
+	resp.Warning = queryResp.Warning
+
+	return resp, nil
+}

pkg/modules/inframonitoring/implinframonitoring/namespaces.go

@@ -0,0 +1,121 @@
+package implinframonitoring
+
+import (
+	"context"
+	"slices"
+
+	"github.com/SigNoz/signoz/pkg/types/inframonitoringtypes"
+	qbtypes "github.com/SigNoz/signoz/pkg/types/querybuildertypes/querybuildertypesv5"
+	"github.com/SigNoz/signoz/pkg/valuer"
+)
+
+// buildNamespaceRecords assembles the page records. Pod phase counts come from
+// phaseCounts in both modes; every row is a group of pods, so there's no
+// per-row "current phase" concept (unlike pods/nodes list mode).
+func buildNamespaceRecords(
+	resp *qbtypes.QueryRangeResponse,
+	pageGroups []map[string]string,
+	groupBy []qbtypes.GroupByKey,
+	metadataMap map[string]map[string]string,
+	phaseCounts map[string]podPhaseCounts,
+) []inframonitoringtypes.NamespaceRecord {
+	metricsMap := parseFullQueryResponse(resp, groupBy)
+
+	records := make([]inframonitoringtypes.NamespaceRecord, 0, len(pageGroups))
+	for _, labels := range pageGroups {
+		compositeKey := compositeKeyFromLabels(labels, groupBy)
+		namespaceName := labels[namespaceNameAttrKey]
+
+		record := inframonitoringtypes.NamespaceRecord{ // initialize with default values
+			NamespaceName:   namespaceName,
+			NamespaceCPU:    -1,
+			NamespaceMemory: -1,
+			Meta:            map[string]any{},
+		}
+
+		if metrics, ok := metricsMap[compositeKey]; ok {
+			if v, exists := metrics["A"]; exists {
+				record.NamespaceCPU = v
+			}
+			if v, exists := metrics["D"]; exists {
+				record.NamespaceMemory = v
+			}
+		}
+
+		if phaseCountsForGroup, ok := phaseCounts[compositeKey]; ok {
+			record.PendingPodCount = phaseCountsForGroup.Pending
+			record.RunningPodCount = phaseCountsForGroup.Running
+			record.SucceededPodCount = phaseCountsForGroup.Succeeded
+			record.FailedPodCount = phaseCountsForGroup.Failed
+			record.UnknownPodCount = phaseCountsForGroup.Unknown
+		}
+
+		if attrs, ok := metadataMap[compositeKey]; ok {
+			for k, v := range attrs {
+				record.Meta[k] = v
+			}
+		}
+
+		records = append(records, record)
+	}
+	return records
+}
+
+func (m *module) getTopNamespaceGroups(
+	ctx context.Context,
+	orgID valuer.UUID,
+	req *inframonitoringtypes.PostableNamespaces,
+	metadataMap map[string]map[string]string,
+) ([]map[string]string, error) {
+	orderByKey := req.OrderBy.Key.Name
+	queryNamesForOrderBy := orderByToNamespacesQueryNames[orderByKey]
+	rankingQueryName := queryNamesForOrderBy[len(queryNamesForOrderBy)-1]
+
+	topReq := &qbtypes.QueryRangeRequest{
+		Start:       uint64(req.Start),
+		End:         uint64(req.End),
+		RequestType: qbtypes.RequestTypeScalar,
+		CompositeQuery: qbtypes.CompositeQuery{
+			Queries: make([]qbtypes.QueryEnvelope, 0, len(queryNamesForOrderBy)),
+		},
+	}
+
+	for _, envelope := range m.newNamespacesTableListQuery().CompositeQuery.Queries {
+		if !slices.Contains(queryNamesForOrderBy, envelope.GetQueryName()) {
+			continue
+		}
+		copied := envelope
+		if copied.Type == qbtypes.QueryTypeBuilder {
+			existingExpr := ""
+			if f := copied.GetFilter(); f != nil {
+				existingExpr = f.Expression
+			}
+			reqFilterExpr := ""
+			if req.Filter != nil {
+				reqFilterExpr = req.Filter.Expression
+			}
+			merged := mergeFilterExpressions(existingExpr, reqFilterExpr)
+			copied.SetFilter(&qbtypes.Filter{Expression: merged})
+			copied.SetGroupBy(req.GroupBy)
+		}
+		topReq.CompositeQuery.Queries = append(topReq.CompositeQuery.Queries, copied)
+	}
+
+	resp, err := m.querier.QueryRange(ctx, orgID, topReq)
+	if err != nil {
+		return nil, err
+	}
+
+	allMetricGroups := parseAndSortGroups(resp, rankingQueryName, req.GroupBy, req.OrderBy.Direction)
+	return paginateWithBackfill(allMetricGroups, metadataMap, req.GroupBy, req.Offset, req.Limit), nil
+}
+
+func (m *module) getNamespacesTableMetadata(ctx context.Context, req *inframonitoringtypes.PostableNamespaces) (map[string]map[string]string, error) {
+	var nonGroupByAttrs []string
+	for _, key := range namespaceAttrKeysForMetadata {
+		if !isKeyInGroupByAttrs(req.GroupBy, key) {
+			nonGroupByAttrs = append(nonGroupByAttrs, key)
+		}
+	}
+	return m.getMetadata(ctx, namespacesTableMetricNamesList, req.GroupBy, nonGroupByAttrs, req.Filter, req.Start, req.End)
+}

pkg/modules/inframonitoring/implinframonitoring/namespaces_constants.go

@@ -0,0 +1,92 @@
+package implinframonitoring
+
+import (
+	"github.com/SigNoz/signoz/pkg/types/inframonitoringtypes"
+	"github.com/SigNoz/signoz/pkg/types/metrictypes"
+	qbtypes "github.com/SigNoz/signoz/pkg/types/querybuildertypes/querybuildertypesv5"
+	"github.com/SigNoz/signoz/pkg/types/telemetrytypes"
+)
+
+const (
+	namespaceNameAttrKey = "k8s.namespace.name"
+)
+
+var namespaceNameGroupByKey = qbtypes.GroupByKey{
+	TelemetryFieldKey: telemetrytypes.TelemetryFieldKey{
+		Name:          namespaceNameAttrKey,
+		FieldContext:  telemetrytypes.FieldContextResource,
+		FieldDataType: telemetrytypes.FieldDataTypeString,
+	},
+}
+
+// namespacesTableMetricNamesList drives the existence/retention check.
+// Includes k8s.pod.phase so the response short-circuits cleanly when a
+// cluster doesn't ship the metric — even though phase isn't part of the
+// QB composite query (it's queried separately via getPerGroupPodPhaseCounts).
+var namespacesTableMetricNamesList = []string{
+	"k8s.pod.cpu.usage",
+	"k8s.pod.memory.working_set",
+	"k8s.pod.phase",
+}
+
+var namespaceAttrKeysForMetadata = []string{
+	"k8s.namespace.name",
+	"k8s.cluster.name",
+}
+
+var orderByToNamespacesQueryNames = map[string][]string{
+	inframonitoringtypes.NamespacesOrderByCPU:    {"A"},
+	inframonitoringtypes.NamespacesOrderByMemory: {"D"},
+}
+
+// newNamespacesTableListQuery builds the composite QB v5 request for the namespaces list.
+// Pod phase counts are derived separately via getPerGroupPodPhaseCounts (works for both
+// list and grouped_list modes), so no phase query is included here.
+// Query letters A and D are kept aligned with the v1 implementation.
+func (m *module) newNamespacesTableListQuery() *qbtypes.QueryRangeRequest {
+	queries := []qbtypes.QueryEnvelope{
+		// Query A: CPU usage — sum of pod CPU within the group.
+		{
+			Type: qbtypes.QueryTypeBuilder,
+			Spec: qbtypes.QueryBuilderQuery[qbtypes.MetricAggregation]{
+				Name:   "A",
+				Signal: telemetrytypes.SignalMetrics,
+				Aggregations: []qbtypes.MetricAggregation{
+					{
+						MetricName:       "k8s.pod.cpu.usage",
+						TimeAggregation:  metrictypes.TimeAggregationAvg,
+						SpaceAggregation: metrictypes.SpaceAggregationSum,
+						ReduceTo:         qbtypes.ReduceToAvg,
+					},
+				},
+				GroupBy:  []qbtypes.GroupByKey{namespaceNameGroupByKey},
+				Disabled: false,
+			},
+		},
+		// Query D: Memory working set — sum of pod memory within the group.
+		{
+			Type: qbtypes.QueryTypeBuilder,
+			Spec: qbtypes.QueryBuilderQuery[qbtypes.MetricAggregation]{
+				Name:   "D",
+				Signal: telemetrytypes.SignalMetrics,
+				Aggregations: []qbtypes.MetricAggregation{
+					{
+						MetricName:       "k8s.pod.memory.working_set",
+						TimeAggregation:  metrictypes.TimeAggregationAvg,
+						SpaceAggregation: metrictypes.SpaceAggregationSum,
+						ReduceTo:         qbtypes.ReduceToAvg,
+					},
+				},
+				GroupBy:  []qbtypes.GroupByKey{namespaceNameGroupByKey},
+				Disabled: false,
+			},
+		},
+	}
+
+	return &qbtypes.QueryRangeRequest{
+		RequestType: qbtypes.RequestTypeScalar,
+		CompositeQuery: qbtypes.CompositeQuery{
+			Queries: queries,
+		},
+	}
+}

pkg/modules/inframonitoring/inframonitoring.go

@@ -12,10 +12,12 @@ type Handler interface {
 	ListHosts(http.ResponseWriter, *http.Request)
 	ListPods(http.ResponseWriter, *http.Request)
 	ListNodes(http.ResponseWriter, *http.Request)
+	ListNamespaces(http.ResponseWriter, *http.Request)
 }
 
 type Module interface {
 	ListHosts(ctx context.Context, orgID valuer.UUID, req *inframonitoringtypes.PostableHosts) (*inframonitoringtypes.Hosts, error)
 	ListPods(ctx context.Context, orgID valuer.UUID, req *inframonitoringtypes.PostablePods) (*inframonitoringtypes.Pods, error)
 	ListNodes(ctx context.Context, orgID valuer.UUID, req *inframonitoringtypes.PostableNodes) (*inframonitoringtypes.Nodes, error)
+	ListNamespaces(ctx context.Context, orgID valuer.UUID, req *inframonitoringtypes.PostableNamespaces) (*inframonitoringtypes.Namespaces, error)
 }

pkg/types/inframonitoringtypes/namespaces.go

@@ -0,0 +1,103 @@
+package inframonitoringtypes
+
+import (
+	"encoding/json"
+	"slices"
+
+	"github.com/SigNoz/signoz/pkg/errors"
+	qbtypes "github.com/SigNoz/signoz/pkg/types/querybuildertypes/querybuildertypesv5"
+)
+
+type Namespaces struct {
+	Type                   ResponseType           `json:"type" required:"true"`
+	Records                []NamespaceRecord      `json:"records" required:"true"`
+	Total                  int                    `json:"total" required:"true"`
+	RequiredMetricsCheck   RequiredMetricsCheck   `json:"requiredMetricsCheck" required:"true"`
+	EndTimeBeforeRetention bool                   `json:"endTimeBeforeRetention" required:"true"`
+	Warning                *qbtypes.QueryWarnData `json:"warning,omitempty"`
+}
+
+type NamespaceRecord struct {
+	NamespaceName     string                 `json:"namespaceName" required:"true"`
+	NamespaceCPU      float64                `json:"namespaceCPU" required:"true"`
+	NamespaceMemory   float64                `json:"namespaceMemory" required:"true"`
+	PendingPodCount   int                    `json:"pendingPodCount" required:"true"`
+	RunningPodCount   int                    `json:"runningPodCount" required:"true"`
+	SucceededPodCount int                    `json:"succeededPodCount" required:"true"`
+	FailedPodCount    int                    `json:"failedPodCount" required:"true"`
+	UnknownPodCount   int                    `json:"unknownPodCount" required:"true"`
+	Meta              map[string]interface{} `json:"meta" required:"true"`
+}
+
+// PostableNamespaces is the request body for the v2 namespaces list API.
+type PostableNamespaces struct {
+	Start   int64                `json:"start" required:"true"`
+	End     int64                `json:"end" required:"true"`
+	Filter  *qbtypes.Filter      `json:"filter"`
+	GroupBy []qbtypes.GroupByKey `json:"groupBy"`
+	OrderBy *qbtypes.OrderBy     `json:"orderBy"`
+	Offset  int                  `json:"offset"`
+	Limit   int                  `json:"limit" required:"true"`
+}
+
+// Validate ensures PostableNamespaces contains acceptable values.
+func (req *PostableNamespaces) Validate() error {
+	if req == nil {
+		return errors.NewInvalidInputf(errors.CodeInvalidInput, "request is nil")
+	}
+
+	if req.Start <= 0 {
+		return errors.NewInvalidInputf(
+			errors.CodeInvalidInput,
+			"invalid start time %d: start must be greater than 0",
+			req.Start,
+		)
+	}
+
+	if req.End <= 0 {
+		return errors.NewInvalidInputf(
+			errors.CodeInvalidInput,
+			"invalid end time %d: end must be greater than 0",
+			req.End,
+		)
+	}
+
+	if req.Start >= req.End {
+		return errors.NewInvalidInputf(
+			errors.CodeInvalidInput,
+			"invalid time range: start (%d) must be less than end (%d)",
+			req.Start,
+			req.End,
+		)
+	}
+
+	if req.Limit < 1 || req.Limit > 5000 {
+		return errors.NewInvalidInputf(errors.CodeInvalidInput, "limit must be between 1 and 5000")
+	}
+
+	if req.Offset < 0 {
+		return errors.NewInvalidInputf(errors.CodeInvalidInput, "offset cannot be negative")
+	}
+
+	if req.OrderBy != nil {
+		if !slices.Contains(NamespacesValidOrderByKeys, req.OrderBy.Key.Name) {
+			return errors.NewInvalidInputf(errors.CodeInvalidInput, "invalid order by key: %s", req.OrderBy.Key.Name)
+		}
+		if req.OrderBy.Direction != qbtypes.OrderDirectionAsc && req.OrderBy.Direction != qbtypes.OrderDirectionDesc {
+			return errors.NewInvalidInputf(errors.CodeInvalidInput, "invalid order by direction: %s", req.OrderBy.Direction)
+		}
+	}
+
+	return nil
+}
+
+// UnmarshalJSON validates input immediately after decoding.
+func (req *PostableNamespaces) UnmarshalJSON(data []byte) error {
+	type raw PostableNamespaces
+	var decoded raw
+	if err := json.Unmarshal(data, &decoded); err != nil {
+		return err
+	}
+	*req = PostableNamespaces(decoded)
+	return req.Validate()
+}

pkg/types/inframonitoringtypes/namespaces_constants.go

@@ -0,0 +1,11 @@
+package inframonitoringtypes
+
+const (
+	NamespacesOrderByCPU    = "cpu"
+	NamespacesOrderByMemory = "memory"
+)
+
+var NamespacesValidOrderByKeys = []string{
+	NamespacesOrderByCPU,
+	NamespacesOrderByMemory,
+}

pkg/types/inframonitoringtypes/namespaces_test.go

@@ -0,0 +1,237 @@
+package inframonitoringtypes
+
+import (
+	"testing"
+
+	"github.com/SigNoz/signoz/pkg/errors"
+	qbtypes "github.com/SigNoz/signoz/pkg/types/querybuildertypes/querybuildertypesv5"
+	"github.com/SigNoz/signoz/pkg/types/telemetrytypes"
+	"github.com/SigNoz/signoz/pkg/valuer"
+	"github.com/stretchr/testify/require"
+)
+
+func TestPostableNamespaces_Validate(t *testing.T) {
+	tests := []struct {
+		name    string
+		req     *PostableNamespaces
+		wantErr bool
+	}{
+		{
+			name: "valid request",
+			req: &PostableNamespaces{
+				Start:  1000,
+				End:    2000,
+				Limit:  100,
+				Offset: 0,
+			},
+			wantErr: false,
+		},
+		{
+			name:    "nil request",
+			req:     nil,
+			wantErr: true,
+		},
+		{
+			name: "start time zero",
+			req: &PostableNamespaces{
+				Start:  0,
+				End:    2000,
+				Limit:  100,
+				Offset: 0,
+			},
+			wantErr: true,
+		},
+		{
+			name: "start time negative",
+			req: &PostableNamespaces{
+				Start:  -1000,
+				End:    2000,
+				Limit:  100,
+				Offset: 0,
+			},
+			wantErr: true,
+		},
+		{
+			name: "end time zero",
+			req: &PostableNamespaces{
+				Start:  1000,
+				End:    0,
+				Limit:  100,
+				Offset: 0,
+			},
+			wantErr: true,
+		},
+		{
+			name: "start time greater than end time",
+			req: &PostableNamespaces{
+				Start:  2000,
+				End:    1000,
+				Limit:  100,
+				Offset: 0,
+			},
+			wantErr: true,
+		},
+		{
+			name: "start time equal to end time",
+			req: &PostableNamespaces{
+				Start:  1000,
+				End:    1000,
+				Limit:  100,
+				Offset: 0,
+			},
+			wantErr: true,
+		},
+		{
+			name: "limit zero",
+			req: &PostableNamespaces{
+				Start:  1000,
+				End:    2000,
+				Limit:  0,
+				Offset: 0,
+			},
+			wantErr: true,
+		},
+		{
+			name: "limit negative",
+			req: &PostableNamespaces{
+				Start:  1000,
+				End:    2000,
+				Limit:  -10,
+				Offset: 0,
+			},
+			wantErr: true,
+		},
+		{
+			name: "limit exceeds max",
+			req: &PostableNamespaces{
+				Start:  1000,
+				End:    2000,
+				Limit:  5001,
+				Offset: 0,
+			},
+			wantErr: true,
+		},
+		{
+			name: "offset negative",
+			req: &PostableNamespaces{
+				Start:  1000,
+				End:    2000,
+				Limit:  100,
+				Offset: -5,
+			},
+			wantErr: true,
+		},
+		{
+			name: "orderBy nil is valid",
+			req: &PostableNamespaces{
+				Start:  1000,
+				End:    2000,
+				Limit:  100,
+				Offset: 0,
+			},
+			wantErr: false,
+		},
+		{
+			name: "orderBy with valid key cpu and direction asc",
+			req: &PostableNamespaces{
+				Start:  1000,
+				End:    2000,
+				Limit:  100,
+				Offset: 0,
+				OrderBy: &qbtypes.OrderBy{
+					Key: qbtypes.OrderByKey{
+						TelemetryFieldKey: telemetrytypes.TelemetryFieldKey{
+							Name: NamespacesOrderByCPU,
+						},
+					},
+					Direction: qbtypes.OrderDirectionAsc,
+				},
+			},
+			wantErr: false,
+		},
+		{
+			name: "orderBy with valid key memory and direction desc",
+			req: &PostableNamespaces{
+				Start:  1000,
+				End:    2000,
+				Limit:  100,
+				Offset: 0,
+				OrderBy: &qbtypes.OrderBy{
+					Key: qbtypes.OrderByKey{
+						TelemetryFieldKey: telemetrytypes.TelemetryFieldKey{
+							Name: NamespacesOrderByMemory,
+						},
+					},
+					Direction: qbtypes.OrderDirectionDesc,
+				},
+			},
+			wantErr: false,
+		},
+		{
+			name: "orderBy with pod_phase key is rejected",
+			req: &PostableNamespaces{
+				Start:  1000,
+				End:    2000,
+				Limit:  100,
+				Offset: 0,
+				OrderBy: &qbtypes.OrderBy{
+					Key: qbtypes.OrderByKey{
+						TelemetryFieldKey: telemetrytypes.TelemetryFieldKey{
+							Name: "pod_phase",
+						},
+					},
+					Direction: qbtypes.OrderDirectionDesc,
+				},
+			},
+			wantErr: true,
+		},
+		{
+			name: "orderBy with invalid key",
+			req: &PostableNamespaces{
+				Start:  1000,
+				End:    2000,
+				Limit:  100,
+				Offset: 0,
+				OrderBy: &qbtypes.OrderBy{
+					Key: qbtypes.OrderByKey{
+						TelemetryFieldKey: telemetrytypes.TelemetryFieldKey{
+							Name: "unknown",
+						},
+					},
+					Direction: qbtypes.OrderDirectionDesc,
+				},
+			},
+			wantErr: true,
+		},
+		{
+			name: "orderBy with valid key but invalid direction",
+			req: &PostableNamespaces{
+				Start:  1000,
+				End:    2000,
+				Limit:  100,
+				Offset: 0,
+				OrderBy: &qbtypes.OrderBy{
+					Key: qbtypes.OrderByKey{
+						TelemetryFieldKey: telemetrytypes.TelemetryFieldKey{
+							Name: NamespacesOrderByMemory,
+						},
+					},
+					Direction: qbtypes.OrderDirection{String: valuer.NewString("invalid")},
+				},
+			},
+			wantErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := tt.req.Validate()
+			if tt.wantErr {
+				require.Error(t, err)
+				require.True(t, errors.Ast(err, errors.TypeInvalidInput), "expected error to be of type InvalidInput")
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+}