linkerd: Add config reference docs

Signed-off-by: Suraj Deshmukh <suraj@kinvolk.io>

docs/configuration-reference/components/linkerd.md

@@ -0,0 +1,58 @@
+# Linkerd configuration reference for Lokomotive
+
+## Contents
+
+* [Introduction](#introduction)
+* [Prerequisites](#prerequisites)
+* [Configuration](#configuration)
+* [Attribute reference](#attribute-reference)
+* [Applying](#applying)
+* [Deleting](#deleting)
+
+## Introduction
+
+Linkerd is an open-source, cloud-native and lightweight service mesh. Linkerd uses sidecar proxy (linkerd-proxy) to create a mesh among all pods. Control plane components are installed in linkerd namespace.
+
+> **NOTE**: This is an **unsupported and experimental component**. It is not recommended to use this in production. The UX of this component can change anytime as it is tested overtime. If there are fundamental problems with the component then it could be removed without prior notice.
+
+## Prerequisites
+
+* A Lokomotive cluster accessible via `kubectl`.
+
+## Configuration
+
+Linkerd configuration example:
+
+```tf
+component "experimental-linkerd" {
+  controller_replicas = 2
+  enable_monitoring   = true
+  prometheus_url      = "http://prometheus-operator-prometheus.monitoring:9090"
+}
+```
+
+## Attribute reference
+
+Table of all the arguments accepted by the component.
+
+| Argument              | Description                                                                                                                                                                    | Default | Type      | Required |
+|-----------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------|-----------|----------|
+| `enable_monitoring`   | Enable Monitoring for the Linkerd control plane components. Make sure that the [Prometheus Operator](../../how-to-guides/monitoring-with-prometheus-operator.md) is installed. | `false` | `bool`    | false    |
+| `controller_replicas` | Number of replicas of control plane components like: `controller`, `destination`, `identity`, `proxy-injector`, `sp-validator`, `tab`.                                         | `1`     | `integer` | false    |
+| `prometheus_url`      | URL of the external prometheus, Linkerd will scrape its control plane metrics from this Prometheus instance.                                                                   | `""`    | `string`  | false    |
+
+## Applying
+
+To apply the component:
+
+```bash
+lokoctl component apply experimental-linkerd
+```
+
+## Deleting
+
+To destroy the component:
+
+```bash
+lokoctl component delete experimental-linkerd --delete-namespace
+```