Recommended changes

Author: shahsahil264

modules/control-plane-latency.adoc

@@ -6,4 +6,15 @@
 [id="control-plane-latency_{context}"]
 = Recommended Control Plane latency for reliable clusters
 
-We recommend inducing 15ms latency, for the cluster to function normally and to avoid critical alerts such as KubeAPIErrorBudgetBurn and etcdGRPCRequestsSlow.
+It's recommended to ensure that the latency between each of the control plane nodes is within 15ms to ensure performant and reliable cluster. Some of the metrics to keep track of includes etcd grpc requests latency, fysnc latency and any critical alerts. Here are the PromQL queries:
+
++
+[source,terminal]
+----
+histogram_quantile(0.99, sum(rate(grpc_server_handling_seconds_bucket{job=~".*etcd.*", grpc_method!="Defragment", grpc_type="unary"}[5m])) without(grpc_type)) < 0.15
+
+avg_over_time(histogram_quantile(0.99, rate(etcd_disk_wal_fsync_duration_seconds_bucket[2m]))[10m:]) < 1
+
+ALERTS{severity="critical", alertstate="firing"} > 0
+
+----