s/kube_node_info/kube_node_role

Use kube_node_role{role="control-plane"} (see [1] and [2]) to estimate if the cluster is HA or not.
* [1]: https://github.com/search?q=repo%3Akubernetes%2Fkube-state-metrics%20kube_node_role&type=code
* [2]: https://kubernetes.io/docs/reference/labels-annotations-taints/#node-role-kubernetes-io-control-plane

Also drop any thresholds as they would lead to false positives.

Author: rexagod

alerts/resource_alerts.libsonnet

@@ -37,7 +37,7 @@ local utils = import '../lib/utils.libsonnet';
           if $._config.showMultiCluster then {
             expr: |||
               (sum(namespace_cpu:kube_pod_container_resource_requests:sum{%(ignoringOverprovisionedWorkloadSelector)s}) by (%(clusterLabel)s) -
-              0.85 * sum(kube_node_status_allocatable{%(kubeStateMetricsSelector)s,resource="cpu"}) by (%(clusterLabel)s) > 0
+              sum(kube_node_status_allocatable{%(kubeStateMetricsSelector)s,resource="cpu"}) by (%(clusterLabel)s) > 0
               and
               count by (cluster) (max by (cluster, node) (kube_node_role{role="control-plane"})) < 3)
               or
@@ -54,7 +54,7 @@ local utils = import '../lib/utils.libsonnet';
           } else {
             expr: |||
               (sum(namespace_cpu:kube_pod_container_resource_requests:sum{%(ignoringOverprovisionedWorkloadSelector)s}) -
-              0.85 * sum(kube_node_status_allocatable{resource="cpu", %(kubeStateMetricsSelector)s}) > 0
+              sum(kube_node_status_allocatable{resource="cpu", %(kubeStateMetricsSelector)s}) > 0
               and
               count(max by (node) (kube_node_role{role="control-plane"})) < 3)
               or
@@ -82,7 +82,7 @@ local utils = import '../lib/utils.libsonnet';
           if $._config.showMultiCluster then {
             expr: |||
               (sum(namespace_memory:kube_pod_container_resource_requests:sum{%(ignoringOverprovisionedWorkloadSelector)s}) by (%(clusterLabel)s) -
-              0.85 * sum(kube_node_status_allocatable{resource="memory", %(kubeStateMetricsSelector)s}) by (%(clusterLabel)s) > 0
+              sum(kube_node_status_allocatable{resource="memory", %(kubeStateMetricsSelector)s}) by (%(clusterLabel)s) > 0
               and
               count by (cluster) (max by (cluster, node) (kube_node_role{role="control-plane"})) < 3)
               or
@@ -99,7 +99,7 @@ local utils = import '../lib/utils.libsonnet';
           } else {
             expr: |||
               (sum(namespace_memory:kube_pod_container_resource_requests:sum{%(ignoringOverprovisionedWorkloadSelector)s}) -
-              0.85 * sum(kube_node_status_allocatable{resource="memory", %(kubeStateMetricsSelector)s}) > 0
+              sum(kube_node_status_allocatable{resource="memory", %(kubeStateMetricsSelector)s}) > 0
               and
               count(max by (node) (kube_node_role{role="control-plane"})) < 3)
               or