transform SLO into SLI (#292)

docs/modules/ROOT/pages/explanations/slos.adoc → docs/modules/ROOT/pages/explanations/slis.adoc

@@ -1,13 +1,12 @@
-= Service Level Objectives
+= Service Level Indicator (SLI)
+:page-aliases: explanations/slos.adoc
 
-APPUiO Managed OpenShift 4 comes with a collection of https://sre.google/sre-book/service-level-objectives/[service level objectives (SLOs)].
-This document defines and explains these SLOs.
-An APPUiO Managed cluster should meet these objectives to provide the expected service level to our customers.
+APPUiO Managed OpenShift comes with a collection of https://sre.google/sre-book/service-level-objectives/[service level indicators (SLIs)].
+This document defines and explains these SLIs.
+All of the SLIs are in the scope of the https://products.vshn.ch/service_levels.html["Guaranteed Availability" Service Level].
 
-We use the SLOs and https://sre.google/workbook/alerting-on-slos/#6-multiwindow-multi-burn-rate-alerts[Multiwindow, Mulit-Brun-Rate Alerts] as the basis of our on-call alerting.
+We use the SLIs and https://sre.google/workbook/alerting-on-slos/#6-multiwindow-multi-burn-rate-alerts[Multiwindow, Mulit-Burn-Rate Alerts] as the basis of our on-call alerting.
 
-IMPORTANT: These are internal service level *objectives*, not service level *agreements*.
-We don't guarantee to meet these objectives at all times.
 
 == Ingress
 
@@ -17,7 +16,7 @@ If the workloads running on the cluster aren't accessible, it might as well be d
 === Canary
 
 ****
-*99.75% of all HTTP probes to a canary application succeed*
+*HTTP probes to a canary application*
 ****
 
 Probes are sent every minute from the ingress operator, inside the cluster, to the external address of the canary target.
@@ -71,11 +70,10 @@ If the API isn't available, users can't change configuration or run new workload
 
 A misbehaving Kubernetes API directly impacts the service level.
 
-
 === Request Error Rate
 
 ****
-*99.9% of all requests to the Kubernetes API server succeed or are invalid*
+*Requests to the Kubernetes API server succeed or are invalid*
 ****
 
 This is measured directly at the API server through the following metrics.
@@ -95,7 +93,7 @@ NOTE: We only look for HTTP 5xx errors, which indicate a server side error, and
 === Uptime
 
 ****
-*99.9% of all HTTP probes to the Kubernetes API server succeed*
+*HTTP probes to the Kubernetes API server succeed*
 ****
 
 Probes are sent every 10 seconds from a blackbox exporter inside the cluster to the readiness endpoint of the Kubernetes API server.
@@ -112,7 +110,7 @@ This ability is essential and directly impacts the service level.
 === Canary
 
 ****
-*99.75% of canary pods start successfully*
+*Canary pods start successfully*
 ****
 
 A controller starts a known good canary pod every minute and checks if it successfully started after 3 minutes.
@@ -128,7 +126,7 @@ Any storage issues directly impacts the service level for users.
 === CSI Operations
 
 ****
-*99.5% of all CSI operations complete successfully*
+*CSI operations complete successfully*
 ****
 
 CSI operations are any interactions of the kubelet or controller-manager with the CSI provider.
@@ -159,7 +157,7 @@ Without it, users can't reliably access their workload and even moderate packet
 === Packet Loss
 
 ****
-*99.5% of all ICMP pings between canary pods succeed*
+*ICMP pings between canary pods succeed*
 ****
 
 A network canary daemonset starts a canary pod on every node.

docs/modules/ROOT/partials/nav.adoc

@@ -165,7 +165,7 @@
 
 * Monitoring
 ** xref:oc4:ROOT:explanations/cluster_monitoring.adoc[]
-** xref:oc4:ROOT:explanations/slos.adoc[]
+** xref:oc4:ROOT:explanations/slis.adoc[]
 ** xref:oc4:ROOT:how-tos/monitoring/global-monitoring.adoc[]
 ** xref:oc4:ROOT:how-tos/monitoring/handle_alerts.adoc[]
 ** xref:oc4:ROOT:how-tos/monitoring/remove_rules.adoc[]