add cores and memory limits count metrics

This change adds metrics for `cores_limits_counts` and
`memory_limits_counts` which each have one label with two possible
values (`minimum` and `maximum`). These metrics are set once during
initialization of the cluster autosacler.

This change also adds the `max_cores_total` metric to the metrics
proposal doc, as it was previously not recorded there.

cluster-autoscaler/main.go

@@ -330,6 +330,8 @@ func buildAutoscaler() (core.Autoscaler, error) {
 	// These metrics should be published only once.
 	metrics.UpdateNapEnabled(autoscalingOptions.NodeAutoprovisioningEnabled)
 	metrics.UpdateMaxNodesCount(autoscalingOptions.MaxNodesTotal)
+	metrics.UpdateCoresLimitsCount(autoscalingOptions.MinCoresTotal, autoscalingOptions.MaxCoresTotal)
+	metrics.UpdateMemoryLimitsCount(autoscalingOptions.MinMemoryTotal, autoscalingOptions.MaxMemoryTotal)
 
 	// Create autoscaler.
 	return core.NewAutoscaler(opts)

cluster-autoscaler/metrics/metrics.go

@@ -138,6 +138,22 @@ var (
 		},
 	)
 
+	coresLimitsCount = k8smetrics.NewGaugeVec(
+		&k8smetrics.GaugeOpts{
+			Namespace: caNamespace,
+			Name:      "cores_limits_count",
+			Help:      "Minimum and maximum number of cores in the cluster.",
+		}, []string{"direction"},
+	)
+
+	memoryLimitsCount = k8smetrics.NewGaugeVec(
+		&k8smetrics.GaugeOpts{
+			Namespace: caNamespace,
+			Name:      "memory_limits_count",
+			Help:      "Minimum and maximum number of bytes of memory in cluster.",
+		}, []string{"direction"},
+	)
+
 	/**** Metrics related to autoscaler execution ****/
 	lastActivity = k8smetrics.NewGaugeVec(
 		&k8smetrics.GaugeOpts{
@@ -288,6 +304,8 @@ func RegisterAll() {
 	legacyregistry.MustRegister(nodeGroupsCount)
 	legacyregistry.MustRegister(unschedulablePodsCount)
 	legacyregistry.MustRegister(maxNodesCount)
+	legacyregistry.MustRegister(coresLimitsCount)
+	legacyregistry.MustRegister(memoryLimitsCount)
 	legacyregistry.MustRegister(lastActivity)
 	legacyregistry.MustRegister(functionDuration)
 	legacyregistry.MustRegister(functionDurationSummary)
@@ -364,6 +382,18 @@ func UpdateMaxNodesCount(nodesCount int) {
 	maxNodesCount.Set(float64(nodesCount))
 }
 
+// UpdateCoresLimitsCount records the minimum and maximum number of cores in the cluster
+func UpdateCoresLimitsCount(minCoresCount int64, maxCoresCount int64) {
+	coresLimitsCount.WithLabelValues("minimum").Set(float64(minCoresCount))
+	coresLimitsCount.WithLabelValues("maximum").Set(float64(maxCoresCount))
+}
+
+// UpdateMemoryLimitsCount records the minimum and maximum bytes of memory in the cluster
+func UpdateMemoryLimitsCount(minMemoryCount int64, maxMemoryCount int64) {
+	memoryLimitsCount.WithLabelValues("minimum").Set(float64(minMemoryCount))
+	memoryLimitsCount.WithLabelValues("maximum").Set(float64(maxMemoryCount))
+}
+
 // RegisterError records any errors preventing Cluster Autoscaler from working.
 // No more than one error should be recorded per loop.
 func RegisterError(err errors.AutoscalerError) {

cluster-autoscaler/proposals/metrics.md

@@ -27,6 +27,9 @@ All the metrics are prefixed with `cluster_autoscaler_`.
 | nodes_count | Gauge | `state`=<node-state> | Number of nodes in cluster. |
 | unschedulable_pods_count | Gauge | | Number of unschedulable ("Pending") pods in the cluster. |
 | node_groups_count | Gauge | `node_group_type`=<node-group-type> | Number of node groups managed by CA. |
+| max_nodes_count | Gauge | | Maximum number of nodes in all node groups. |
+| cores_limits_count | Gauge | `direction`=<`minimum` or `maximum`> | Minimum and maximum number of cores in the cluster. |
+| memory_limits_count | Gauge | `direction`=<`minimum` or `maximum`> | Minimum and maximum number of bytes of memory in cluster. |
 
 * `cluster_safe_to_autoscale` indicates whether cluster is healthy enough for autoscaling. CA stops all operations if significant number of nodes are unready (by default 33% as of CA 0.5.4).
 * `nodes_count` records the total number of nodes, labeled by node state. Possible