add metrics-operator architecture

Signed-off-by: Rakshit Gondwal <[email protected]>

docs/content/en/docs/concepts/architecture/components/_index.md

@@ -28,36 +28,3 @@ style Scheduler fill:#d8e6f4,stroke:#fff,stroke-width:px,color:#006bb8
 style Lifecycle-Operator fill:#d8e6f4,stroke:#fff,stroke-width:px,color:#006bb8
 style Metrics-Operator fill:#d8e6f4,stroke:#fff,stroke-width:px,color:#006bb8
 ```
-
-**Keptn's Lifecycle Operator** is
-a Kubernetes [operator](https://kubernetes.io/docs/concepts/extend-kubernetes/operator/)
-that automates the deployment and management
-of the Keptn Lifecycle Controller components in a Kubernetes cluster.
-The Keptn Lifecycle Operator contains several controllers for **Keptn CRDs**
-and a **Mutating Webhook**.
-
-Here's a brief overview:
-
-**Keptn CRDs:** Keptn Lifecycle Operator contains
-several controllers that manage and reconcile different types of Keptn CRDs
-such as the Project Controller, Service Controller, and Stage Controller.
-
-**Mutating Webhook:** automatically injects Keptn labels
-and annotations into Kubernetes resources,
-such as deployments and services.
-These labels and annotations are used to enable Keptn's automation
-and monitoring capabilities.
-
-**Keptn's Lifecycle Metrics Operator**
-collects,  processes, and analyzes metrics data from a variety of sources.
-Once collected, this data, can be used to generate a variety of reports
-and dashboards that provide insights into the health and performance of the application and infrastructure.
-
-**Keptn's Lifecycle Scheduler** replaces the
-[Kubernetes scheduler](https://kubernetes.io/docs/concepts/scheduling-eviction/kube-scheduler/)
-to allow users to schedule events and tasks to occur
-at specific times during the application lifecycle.
-The Lifecycle Scheduler can trigger events such as
-deployment, testing, and remediation at specific times or intervals.
-The Keptn Scheduler guarantees that Pods are initiated only after
-the Pre-Deployment checks are completed.

docs/content/en/docs/concepts/architecture/components/lifecycle-operator/_index.md

@@ -0,0 +1,28 @@
+---
+title: Keptn's Lifecycle Operator
+linktitle: Lifecycle Operator
+description: Basic understanding of Lifecycle Operator
+weight: 80
+cascade:
+---
+
+### Lifecycle Operator
+
+**Keptn's Lifecycle Operator** is
+a Kubernetes [operator](https://kubernetes.io/docs/concepts/extend-kubernetes/operator/)
+that automates the deployment and management
+of the Keptn Lifecycle Controller components in a Kubernetes cluster.
+The Keptn Lifecycle Operator contains several controllers for **Keptn CRDs**
+and a **Mutating Webhook**.
+
+Here's a brief overview:
+
+**Keptn CRDs:** Keptn Lifecycle Operator contains
+several controllers that manage and reconcile different types of Keptn CRDs
+such as the Project Controller, Service Controller, and Stage Controller.
+
+**Mutating Webhook:** automatically injects Keptn labels
+and annotations into Kubernetes resources,
+such as deployments and services.
+These labels and annotations are used to enable Keptn's automation
+and monitoring capabilities.

docs/content/en/docs/concepts/architecture/components/metrics-operator/_index.md

@@ -0,0 +1,36 @@
+---
+title: Keptn's Metrics Operator
+linktitle: Metrics Operator
+description: Basic understanding of KLT Metrics Operator
+weight: 80
+cascade:
+---
+
+### Metrics Operator
+
+**Metrics Operator** collects, processes, and analyzes metrics data from a variety of sources. Once collected, this data, can be used to generate a variety of reports and dashboards that provide insights into the health and performance of the application and infrastructure.
+
+The Metrics Operator consists of two main components:
+
+* Metrics Controller
+* Metrics Adapter
+
+```mermaid
+graph TD;
+    Metrics-Operator-->Metrics-Adapter;
+    Metrics-Operator-->Metrics-Controller
+style Metrics-Operator fill:#006bb8,stroke:#fff,stroke-width:px,color:#fff
+style Metrics-Adapter fill:#d8e6f4,stroke:#fff,stroke-width:px,color:#006bb8
+style Metrics-Controller fill:#d8e6f4,stroke:#fff,stroke-width:px,color:#006bb8
+```
+
+**Metrics adapter** is used to expose custom metrics from an application to external monitoring and alerting tools. The adapter exposes custom metrics on a specific endpoint where external monitoring and alerting tools can scrape them. It is an important component of the metrics operator as it allows for the collection and exposure of custom metrics, which can be used to gain insight into the behavior and performance of applications running on a Kubenetes cluster.     
+
+**Metrics controller** is used to fetch metrics from a SLI provider. The controller reconciles a `KeptnMetric` CR and updates it's status with the metric value provided by the selected SLI provider. The steps in which the Controller fetches metrics are given below:
+- It first fetches the `KeptnMetric` object to reconcile.
+- If the object is not found, it returns and lets Kubernetes handle deleting all associated resources.
+- If the object is found, the code checks that if the metric has been updated within the configured interval which is defined in the `Spec.FetchIntervalSeconds`. If not, then it skips reconciling and requeues the request for later.
+- If the metric should be reconciled, it fetches the provider defined in the `Spec.Provider.Name` field.
+- If the provider is not found, it returns and requeues the request for later.
+- If the provider is found, it loads the provider and evaluates the query defined in the `Spec.Query` field.
+- If the evaluation is succesful, it stores the fetched value in the status of the `KeptnMetric` object.

docs/content/en/docs/concepts/architecture/components/scheduler/_index.md

@@ -0,0 +1,16 @@
+---
+title: KLT Scheduler
+linktitle: Scheduler
+description: Basic understanding of KLT Scheduler
+weight: 80
+cascade:
+---
+
+**Keptn's Lifecycle Scheduler** replaces the
+[Kubernetes scheduler](https://kubernetes.io/docs/concepts/scheduling-eviction/kube-scheduler/)
+to allow users to schedule events and tasks to occur
+at specific times during the application lifecycle.
+The Lifecycle Scheduler can trigger events such as
+deployment, testing, and remediation at specific times or intervals.
+The Keptn Scheduler guarantees that Pods are initiated only after
+the Pre-Deployment checks are completed.