docs: add blog post about using Keptn within Argo Workflows

.github/actions/spelling/expect.txt

@@ -684,6 +684,7 @@ webhookcainjection
 webhookmanager
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+whalesay
 whitespaces
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docs/blog/posts/using-keptn-analyses-in-argo-workflows.md

@@ -0,0 +1,179 @@
+---
+date: 2024-05-13
+authors: [bacherfl]
+description: >
+  In this blog post you will learn how to use the Analysis feature of Keptn within Argo Workflows.
+categories:
+  - SRE
+  - Application Performance
+  - Analysis
+comments: true
+---
+
+# Using Keptn Analyses in Argo Workflows
+
+In this blog post we will explore how Keptn
+can be used within [Argo Workflows](https://argoproj.github.io/workflows/) to
+execute load tests using a [KeptnTask](../../docs/reference/crd-reference/task.md), and analyze their results
+afterward using the [Keptn Analysis](../../docs/reference/crd-reference/analysis.md) feature.
+Argo Workflows is a workflow orchestration engine built for Kubernetes, which makes it a perfect fit
+to be used together with Keptn.
+We will achieve this by using the support for [Executor Plugins](https://argo-workflows.readthedocs.io/en/latest/executor_plugins/)
+provided by Argo Workflows.
+This plugin mechanism is an easy way of integrating custom functionality into an Argo Workflow,
+and providing further nodes in the workflow with valuable information, such as the outcome of a Keptn Analysis.
+
+<!-- more -->
+
+## Technologies used for this example
+
+For this, we are using the following technologies:
+
+- The [Keptn Analysis](../../docs/reference/crd-reference/analysis.md) resource
+  defines goals for our metrics and evaluates them.
+- [Argo Workflows](https://argoproj.github.io/workflows/) is the workflow engine.
+- [Prometheus](https://prometheus.io): Provides monitoring data for the application.
+
+## Architecture
+
+The overall architecture of this example is depicted in the diagram below:
+
+![Architecture](./using-keptn-analyses-in-argo-workflows/workflow.png)
+
+Our example workflow consists of two nodes, which do the following:
+
+- The **Load Tests** node creates a `KeptnTask` that executes load tests against
+a sample application.
+Once the tests have finished, the results and the time frame of the `KeptnTask`
+execution are reported back to Argo Workflows.
+- The **Analyse Results** node takes the time frame of the executed load tests as an input parameter
+and creates a Keptn `Analysis` for the given timeframe.
+Using a `KeptnMetricsProvider` which retrieves the metrics for the application from Prometheus,
+the metric values relevant for the analysis are retrieved and evaluated.
+The result of the Analysis is then reported back to Argo Workflows which can then pass
+on the Analysis results to other potential nodes in the workflow.
+
+Both of the workflow nodes are executed using a simple Argo Workflow executor plugin
+hosted in [this repo](https://github.com/bacherfl/argo-keptn-plugin).
+Note, however, that the code in this repo is just a proof of concept and not
+intended for use in production.
+
+## Setting up the environment
+
+In this example, we assume that both Keptn and Argo Workflows are
+already installed on our cluster.
+If this is not the case, and you would like to follow this example,
+please follow the instructions at the respective installation guides:
+
+- [Keptn Installation Guide](https://keptn.sh/stable/docs/installation/)
+- [Argo Workflows Installation Guide](https://argo-workflows.readthedocs.io/en/latest/quick-start/)
+
+The next step is to install the [Keptn extension for Argo Workflows (unofficial PoC implementation)](https://github.com/bacherfl/argo-keptn-plugin).
+This is done by applying the `ConfigMap` that enables the plugin within Argo workflows,
+and the required RBAC configuration for the plugin to be able to interact
+with Keptn resources:
+
+```shell
+kubectl apply -f https://raw.githubusercontent.com/bacherfl/argo-keptn-plugin/main/config/keptn-executor-plugin-configmap.yaml
+kubectl apply -f https://raw.githubusercontent.com/bacherfl/argo-keptn-plugin/main/config/rbac.yaml
+```
+
+## Defining the load test KeptnTaskDefinition
+
+The load tests against our sample application are executed
+using a `KeptnTask`.
+The related `KeptnTaskDefinition` looks as follows:
+
+```yaml
+{% include "./using-keptn-analyses-in-argo-workflows/load-generator-task.yaml" %}
+```
+
+This task simply creates some load by sending a curl request
+to the sample application for a duration of one minute.
+
+## Defining the AnalysisValueTemplates
+
+Now we are going to define the queries for the metrics we would like to analyse:
+
+- The response time of the demo service
+- The error rate of the demo service
+
+Below are the `AnalysisValueTemplate` resources, as well as the
+`KeptnMetricsProvider` resource that points to the Prometheus API
+inside our cluster:
+
+```yaml
+{% include "./using-keptn-analyses-in-argo-workflows/metrics.yaml" %}
+```
+
+Next, we define the `AnalysisDefinition` resource that contains the goals
+for the metrics mentioned above:
+
+```yaml
+{% include "./using-keptn-analyses-in-argo-workflows/analysisdefinition.yaml" %}
+```
+
+Note that the `AnalysisDefinition` used in this example is kept rather simple.
+If you would like to learn more about the possibilities of the
+analysis feature of Keptn, feel free to read more about it
+in [this blog post](./application-performance-analysis.md).
+
+## Putting it all together
+
+Now that we have defined our Keptn resources for executing
+load tests and analysing the performance of our application,
+it is time to put everything together by defining the
+Argo Workflow, which looks like the following:
+
+```yaml
+{% include "./using-keptn-analyses-in-argo-workflows/argo-workflow.yaml" %}
+```
+
+This workflow contains the following steps:
+
+- **execute-load-tests:** Starts a new instance of a `KeptnTask` based on the `loadtests`
+`KeptnTaskDefinition` we created earlier.
+The result of this step contains the `start` and `end` timestamps of the executed load tests.
+- **keptn-analysis:** Runs after the previous node is completed, and accepts the reported
+`start` and `end` timestamps as input parameters.
+This interval is used to create a new instance of an `Analysis` where the response time
+and error rate during this interval is evaluated, using the `AnalysisDefinition` created earlier.
+The overall result (i.e. whether the `Analysis` has passed or not), as well as a detailed breakdown
+of each objective in JSON format is reported back to Argo in the results of the step.
+- **print-result:** Takes both the `start` and `end` timestamps of the load tests, as well
+as the overall `result` of the `Analysis` as input parameters, and prints a message containing
+the result.
+- **print-json**: Takes the JSON object containing the
+analysis objective breakdown of the `keptn-analysis` as an input parameter,
+and stores the received JSON object as an artifact.
+This enables other nodes in a workflow to retrieve that artifact and use the information in it
+as input artifacts.
+Read more about the concept of artifacts in Argo Workflows [here](https://argo-workflows.readthedocs.io/en/latest/walk-through/artifacts/).
+
+## Executing the workflow
+
+The workflow is triggered by navigating to the Argo Workflows UI
+and choosing the **Submit new Workflow** option:
+
+![Triggering the workflows](./using-keptn-analyses-in-argo-workflows/triggering-workflow.png)
+
+After some time, all steps in the workflow are completed,
+and both the time frame of the load test execution,
+and the result of the `Analysis` are visible in
+the Argo Workflows UI:
+
+![Workflow result](./using-keptn-analyses-in-argo-workflows/workflow-result.png)
+
+## Conclusion
+
+In this article we have explored the potential of using Keptn
+to both perform tasks and analyse performance metrics
+within Argo Workflows, and pass the results on to the following steps.
+Hopefully this article provides you with some inspiration of
+how you can make use of Keptn within Argo Workflows -
+If so, we would love to hear about it, and we always welcome any feedback.
+If you have questions or run into any kind of issues,
+feel free to reach out on the
+[#Keptn CNCF Slack channel](https://cloud-native.slack.com/archives/C017GAX90GM)
+or by raising issues in our
+[GitHub repository](https://github.com/keptn/lifecycle-toolkit/issues).

docs/blog/posts/using-keptn-analyses-in-argo-workflows/analysisdefinition.yaml

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+apiVersion: metrics.keptn.sh/v1
+kind: AnalysisDefinition
+metadata:
+  name: my-analysis-definition
+  namespace: simple-go
+spec:
+  objectives:
+    - analysisValueTemplateRef:
+        name: response-time-p95
+      keyObjective: false
+      target:
+        failure:
+          greaterThan:
+            fixedValue: 500m
+        warning:
+          greaterThan:
+            fixedValue: 300m
+      weight: 1
+    - analysisValueTemplateRef:
+        name: error-rate
+      keyObjective: true
+      target:
+        failure:
+          greaterThan:
+            fixedValue: 0
+      weight: 1
+  totalScore:
+    passPercentage: 60
+    warningPercentage: 50

docs/blog/posts/using-keptn-analyses-in-argo-workflows/argo-workflow.yaml

@@ -0,0 +1,115 @@
+metadata:
+  generateName: test-123
+  namespace: argo
+  labels:
+    example: 'true'
+spec:
+  arguments:
+    parameters:
+      - name: workload
+        value: simple-go-service
+  entrypoint: main
+  templates:
+    - name: main
+      dag:
+        tasks:
+          - name: execute-load-tests
+            template: keptn-loadtests
+          - name: analyze
+            template: keptn-analysis
+            dependencies:
+              - execute-load-tests
+            arguments:
+              parameters:
+                - name: query
+                  value: analysis/simple-go/my-analysis-definition/1m/workload=simple-go-service
+                - name: start
+                  value: "{{tasks.execute-load-tests.outputs.parameters.start}}"
+                - name: end
+                  value: "{{tasks.execute-load-tests.outputs.parameters.end}}"
+          - name: print-result
+            dependencies:
+              - analyze
+              - execute-load-tests
+            arguments:
+              parameters:
+                - name: start
+                  value: "{{tasks.execute-load-tests.outputs.parameters.start}}"
+                - name: end
+                  value: "{{tasks.execute-load-tests.outputs.parameters.end}}"
+                - name: result
+                  value: "{{tasks.analyze.outputs.parameters.result}}"
+            template: whalesay
+          - name: print-json
+            dependencies:
+              - analyze
+            arguments:
+              parameters:
+                - name: details
+                  value: "{{tasks.analyze.outputs.parameters.details}}"
+            template: print-json
+
+    - name: keptn-loadtests
+      inputs:
+        parameters:
+          - name: query
+            value: keptntask/simple-go/post-deployment-loadtests
+      outputs:
+        parameters:
+          - name: start
+            valueFrom:
+              jsonPath: '{.output.parameters.start}'
+          - name: end
+            valueFrom:
+              jsonPath: '{.output.parameters.end}'
+      plugin:
+        keptn: {}
+
+    - name: keptn-analysis
+      inputs:
+        parameters:
+          - name: query
+          - name: start
+          - name: end
+      outputs:
+        parameters:
+          - name: result
+            valueFrom:
+              jsonPath: "{.output.parameters.result}"
+          - name: details
+            valueFrom:
+              jsonPath: "{.output.parameters.details}"
+
+      plugin:
+        keptn: {}
+
+    - name: whalesay
+      inputs:
+        parameters:
+          - name: start
+          - name: end
+          - name: result
+      container:
+        image: docker/whalesay:latest
+        command: [sh, -c]
+        args: ["cowsay 'Analysis result for timeframe {{inputs.parameters.start}} - {{inputs.parameters.end}}: {{inputs.parameters.result}}'"]
+
+    - name: print-json
+      inputs:
+        parameters:
+          - name: details
+      container:
+        image: alpine:latest
+        command: [sh, -c]
+        args: ["echo '{{inputs.parameters.details}}' | tee /tmp/result.json"]
+      outputs:
+        artifacts:
+          - name: result
+            path: /tmp/result.json
+            archive:
+              none: {}
+
+  ttlStrategy:
+    secondsAfterCompletion: 300
+  podGC:
+    strategy: OnPodCompletion

docs/blog/posts/using-keptn-analyses-in-argo-workflows/load-generator-task.yaml

@@ -0,0 +1,16 @@
+apiVersion: lifecycle.keptn.sh/v1
+kind: KeptnTaskDefinition
+metadata:
+  name: loadtests
+  namespace: simple-go
+spec:
+  container:
+    - name: loadtests
+      image: curl
+      command: ["sh", "-c"]
+      args:
+        - |
+          for i in $(seq 1 600); do
+            curl -s http://simple-go-service.simple-go:8080
+            sleep 0.1
+          done

docs/blog/posts/using-keptn-analyses-in-argo-workflows/metrics.yaml

@@ -0,0 +1,28 @@
+apiVersion: metrics.keptn.sh/v1
+kind: KeptnMetricsProvider
+metadata:
+  name: my-provider
+  namespace: simple-go
+spec:
+  targetServer: https://prometheus-k8s.monitoring.svc.cluster.local:9090
+  type: prometheus
+---
+apiVersion: metrics.keptn.sh/v1
+kind: AnalysisValueTemplate
+metadata:
+  name: response-time-p95
+  namespace: simple-go
+spec:
+  provider:
+    name: my-provider
+  query: "histogram_quantile(0.95, sum by(le) (rate(http_server_request_latency_seconds_bucket{job='{{.workload}}'}[1m])))"
+---
+apiVersion: metrics.keptn.sh/v1
+kind: AnalysisValueTemplate
+metadata:
+  name: error-rate
+  namespace: simple-go
+spec:
+  provider:
+    name: my-provider
+  query: "rate(http_requests_total{status_code='500', job='{{.workload}}'}[1m]) or on() vector(0)"