Add to docs about Arc Extension

otelcollector/deploy/addon-chart/Readme.md

@@ -40,10 +40,22 @@ ImageTag: https://msazure.visualstudio.com/CloudNativeCompute/_git/aks-rp?path=/
 
 ### **Step 5: Install Helm chart**
 ```
-helm install ama-metrics azure-monitor-metrics-addon/ --values azure-monitor-metrics-addon/values.yaml
+helm upgrade --install ama-metrics azure-monitor-metrics-addon/ --values azure-monitor-metrics-addon/values.yaml
 ```
 
 ### **Step 6: Uninstall helm chart**
 ```
 helm uninstall ama-metrics
-```
+```
+
+# Arc Extension Values
+There are a couple Arc-specific settings that customers can use when installing the ama-metrics extension.
+- `ClusterDistribution` and `CloudEnvironment` are by default the values that are provided by the Arc infrastructure. These values in our chart allow customers to override them if needed.
+- We do not know what Linux distribution the nodes will be using, so we mount both common CA cert directories. Certain node restrictions do not allow directories that do not exist to be created like AKS Edge clusters. In these cases `MountCATrustAnchorsDirectory` and `MountUbuntuCACertDirectory` can be used to set one to `false`.
+
+| Parameter | Description | Default Value | Upstream Arc Cluster Setting |
+|-----------|-------------|---------------|---------------|
+| `ClusterDistribution` | The distribution of the cluster | `Azure.Cluster.Distribution` | yes |
+| `CloudEnvironment` | The cloud environment for the cluster | `Azure.Cluster.Cloud` | yes |
+| `MountCATrustAnchorsDirectory` | Whether to mount CA trust anchors directory | `true` | no |
+| `MountUbuntuCACertDirectory` | Whether to mount Ubuntu CA certificate directory | `true` unless an `aks_edge` distro | no |