docs: add first iteration of analysis documentation

docs/content/en/docs/implementing/slo/_index.md

@@ -0,0 +1,119 @@
+---
+title: Define SLOs/SLIs with Analyses
+description: Understand Analyses in Keptn and how to use them
+weight: 91
+---
+
+The Keptn Metrics Operator implements an SLO/SLI feature set inspired by Keptn v1 under the name of Analysis.
+With an Analysis Definition you can specify multiple Service Level Objectives (SLOs) that will be evaluated in your Analysis.
+At the end of the Analysis the status returns whether your objective failed or passed.
+
+The Analysis result is exposed as an OpenTelemetry metric and can be displayed on dashboard tools, such as Grafana.
+
+Keptn v1 users may use converters for
+[SLOs](https://github.com/keptn/lifecycle-toolkit/blob/main/metrics-operator/converter/slo_converter.md#slo-converter)
+and [SLIs](https://github.com/keptn/lifecycle-toolkit/blob/main/metrics-operator/converter/sli_converter.md#sli-converter)
+to migrate towards Keptn Analysis.
+
+## Keptn Analysis basics
+
+A Keptn Analysis is implemented with three resources:
+
+* [Analysis](https://lifecycle.keptn.sh/docs/crd-ref/metrics/v1alpha3/#analysis) --
+  define the specific configurations and the analysis to report
+* [AnalysisDefinition](https://lifecycle.keptn.sh/docs/crd-ref/metrics/v1alpha3/#analysisdefinition) --
+  define the list of SLOs for an Analysis
+* [AnalysisValueTemplate](https://lifecycle.keptn.sh/docs/crd-ref/metrics/v1alpha3/#analysisvaluetemplate) --
+  define the SLI: the KeptnMetricsProvider and the query to perform for each SLI
+
+### Define Analysis, Analysis Definition and AnalysisValueTemplate
+
+An Analysis customizes the templates defined inside an AnalysisDefinition by adding configuration such as:
+
+* a timeframe that specifies the range for the corresponding query in the AnalysisValueTemplate
+* a map of key/value pairs that can be used to substitute placeholders in the AnalysisValueTemplate
+
+An AnalysisDefinition contains a list of objectives to satisfy.
+Each of these objectives:
+
+* specifies failure or warning target criteria
+* specifies whether the objective is a key objective (its failure would fail the analysis)
+* indicates the weight of the objective on the overall analysis
+* refers to an AnalysisValueTemplate that contains the SLIs, defining the data provider from which to gather the data
+  and how to compute the analysis
+
+In each AnalysisValueTemplate we store the query for the analysis of the SLI.
+You must define a
+[KeptnMetricsProvider](../../yaml-crd-ref/metricsprovider.md) resource
+for each instance of each data provider you are using.
+The template refers to that provider and queries it.
+
+Let's consider the following Analysis:
+
+{{< embed path="/metrics-operator/config/samples/metrics_v1alpha3_analysis.yaml" >}}
+
+This CR sets up the timeframe we are interested in
+as between 5 am and 10 am on the 5th of May 2023,
+and adds a few specific key-value pairs that will be substituted in the query.
+For instance, the query could contain a `{{ .nodename }}` and this value will be substituted with `test`
+
+The definition of this Analysis is referenced by its name and namespace and can be seen here:
+
+{{< embed path="/metrics-operator/config/samples/metrics_v1alpha3_analysisdefinition.yaml" >}}
+
+This simple definition contains a single objective, `response-time-p95`.
+For this objective, there are both
+failure and warning criteria:
+
+* the objective will fail if the percentile 95 is less than 600
+* there will be a warning in case the value is between 300 and 500
+
+The total score shows that this analysis should have an overall score of 90% to pass or 75% to get a warning.
+Since the objective is only one, this means that we either will pass with 100% (response time is less than 600) or fail
+with 0% (slower response time).
+
+The objective points to the corresponding AnalysisValueTemplate:
+{{< embed path="/metrics-operator/config/samples/metrics_v1alpha3_analysisvaluetemplate.yaml" >}}
+
+This template tells us that we will query a provider called `prometheus` using this query:
+
+```shell
+ sum(kube_pod_container_resource_limits{node='{{.nodename}}'}) - sum(kube_node_status_capacity{node='{{.nodename}}'})
+```
+
+At runtime, the metrics operator will try to substitute everything in`{{.variableName }}`
+format with a key-value pair in the Analysis resource,
+so in this case the query would become:
+
+```shell
+ sum(kube_pod_container_resource_limits{node='test'}) - sum(kube_node_status_capacity{node='test'})
+```
+
+The other key-value pairs such as 'project' and 'stage' are just examples of how one could pass to the provider
+information similar to Keptn v1 objectives.
+For a working example you can
+check [here](https://github.com/keptn/lifecycle-toolkit/tree/main/test/testanalysis/analysis-controller-multiple-providers).
+
+## Accessing Analysis
+
+### Retrieve KeptnMetric values with kubectl
+
+Use the `kubectl get` command to retrieve all the `Analyses` in your cluster:
+
+```shell
+kubectl get analyses.metrics.keptn.sh -A
+
+```
+
+This will return something like
+
+```shell
+NAMESPACE   NAME              ANALYSISDEFINITION    STATE   WARNING   PASS
+default     analysis-sample   ed-my-proj-dev-svc1
+```
+
+You can then describe the analysis with:
+
+```shell
+kubectl describe analyses.metrics.keptn.sh analysis-sample -n=default
+```

docs/content/en/docs/migrate/metrics-observe/_index.md

@@ -20,9 +20,7 @@ and Keptn evaluations.
 > **Note**
 The full SLO capabilities
 provided by Keptn v1 such as weighting and scoring
-are currently under development for Keptn.
-You can follow and participate in the design and implementation process at
-[GitHub Epic 1646](https://github.com/keptn/lifecycle-toolkit/issues/1646).
+have a first implementation in the [Analysis](../../implementing/slo/).
 
 Notice the paradigm differences when implementing Keptn evaluations:
 

metrics-operator/config/samples/metrics_v1alpha3_analysis.yaml

@@ -16,7 +16,7 @@ spec:
     project: my-project
     stage: dev
     service: svc1
-    foo: bar # can be any key/value pair; NOT only project/stage/service
+    nodename: test # can be any key/value pair; NOT only project/stage/service
   analysisDefinition:
     name: ed-my-proj-dev-svc1
     namespace: keptn-lifecycle-toolkit-system

metrics-operator/config/samples/metrics_v1alpha3_analysisvaluetemplate.yaml

@@ -12,4 +12,4 @@ metadata:
 spec:
   provider:
     name: prometheus
-  query: "sum(kube_pod_container_resource_limits{resource='{{.Resource}}'}) - sum(kube_node_status_capacity{resource='{{.Resource}}'})"
+  query: "sum(kube_pod_container_resource_limits{node='{{.nodename}}'}) - sum(kube_node_status_capacity{node='{{.nodename}}'})"