add visual explainer for config value propagation (#513)

Author: willcl-ark

README.md

@@ -23,5 +23,6 @@ Monitor and analyze the emergent behaviors of Bitcoin networks.
 - [Lightning Network](/docs/lightning.md)
 - [Scaling](/docs/scaling.md)
 - [Connecting to local nodes](https://github.com/bitcoin-dev-project/warnet/blob/main/docs/)
+- [Understanding network configuration](/docs/config.md)
 
 ![warnet-art](https://raw.githubusercontent.com/bitcoin-dev-project/warnet/main/docs/machines.webp)

docs/config.md

@@ -0,0 +1,51 @@
+# Configuration value propagation
+
+This flowchart illustrates the process of how values for the Bitcoin Core module are handled and deployed using Helm in a Kubernetes environment.
+
+The process is similar for other modules (e.g. fork-observer), but may differ slightly in filenames.
+
+- The process starts with the `values.yaml` file, which contains default values for the Helm chart.
+- There's a decision point to check if user-provided values are available.
+  These are found in the following files:
+    - For config applied to all nodes: `<network_name>/node-defaults.yaml`
+    - For network and per-node config: `<network_name>/network.yaml`
+
+> [!TIP]
+> `values.yaml` can be overridden by `node-defaults.yaml` which can be overridden in turn by `network.yaml`.
+
+- If user-provided values exist, they override the defaults from `values.yaml`. If not, the default values are used.
+- The resulting set of values (either default or overridden) becomes the final set of values used for deployment.
+- These final values are then passed to the Helm templates.
+- The templates (`configmap.yaml`, `service.yaml`, `servicemonitor.yaml`, and `pod.yaml`) use these values to generate the Kubernetes resource definitions.
+- Helm renders these templates, substituting the values into the appropriate places.
+- The rendering process produces the final Kubernetes manifest files.
+- Helm then applies these rendered manifests to the Kubernetes cluster.
+- Kubernetes processes these manifests and creates or updates the corresponding resources in the cluster.
+- The process ends with the resources being deployed or updated in the Kubernetes cluster.
+
+```mermaid
+    graph TD
+        A[Start] --> B[values.yaml]
+        subgraph User Configuration [user config: bottom overrides top]
+            C[node-defaults.yaml]
+            D[network.yaml]
+        end
+        B --> C
+        C --> D
+        D --> F[Final values]
+        F --> I[Templates]
+        I --> J[configmap.yaml]
+        I --> K[service.yaml]
+        I --> L[servicemonitor.yaml]
+        I --> M[pod.yaml]
+        J --> N[Helm renders templates]
+        K --> N
+        L --> N
+        M --> N
+        N --> O[Rendered Kubernetes manifests]
+        O --> P[Helm applies manifests to Kubernetes]
+        P --> Q[Kubernetes creates/updates resources]
+        Q --> R[Resources deployed/updated in cluster]
+```
+
+Users should only concern themselves therefore with setting configuration in the `<network_name>/[network|node-defaults].yaml` files.