Add 2A initialisation process document

docs/architecture.md → docs/architecture/architecture.md

@@ -1,10 +1,7 @@
-# Architecture
-
+# Architectural Overview
 
 Below is a diagram that provides an overview of how Project 2A works.
 
-## Architectural Overview
-
 ```mermaid
 ---
 title: HMC Overview

docs/architecture/initialisation.md

@@ -0,0 +1,17 @@
+# 2A initialisation process
+
+![2A initialisation process](../assets/hmc-initialisation.png)
+
+## The process
+
+1. [helm install hmc](../quick-start/2a-installation.md/#installation-via-helm) brings up the bootstrap components (yellow on the picture above)
+1. hmc-controller-manager set up webhooks to validate its CRs, then cert-manager handles the webhooks’ certificates
+1. hmc-controller-manager generates *Release* object corresponding to the hmc helm chart version
+1. hmc-controller-manager ([release-controller](https://github.com/Mirantis/hmc/blob/main/internal/controller/release_controller.go) inside it) generates template objects (*ProviderTemplate/ClusterTemplate/ServiceTemplate*) corresponding to *Release* to be further processed
+1. hmc-controller-manager generates *HelmRelease* object for every template from p.3 (Important: it includes also hmc helm chart itself)
+1. [Flux](https://github.com/fluxcd/flux2) (source-controller and helm-controller pods) reconciles the *HelmRelease* objects i.e. installs all the helm charts referred to in the templates.
+**After this point the deployment is completely controlled by Flux.**
+1. hmc-controller-manager creates a Management object which refers to the above *Release* and the *ProviderTemplate* objects.
+*Management* object represents the 2A management cluster as a whole.
+The management cluster Day-2 operations (such as [upgrade](../usage/2a-upgrade.md)) are being executed by manipulating the *Release* and *Management* objects.
+1. hmc-controller-manager generates an empty *AccessManagement* object (*TemplateManagement* in older releases). *AccessManagement* defines [access rules](../template/main.md/#template-life-cycle-management) for *ClusterTemplate*/*ServiceTemplate* propagation across user namespaces. Further *AccessManagement* might be edited and used along with admin-created *ClusterTemplateChain* and *ServiceTemplaitChain* objects.

mkdocs.yml

@@ -100,5 +100,7 @@ nav:
       - Overview: credential/main.md
   - RBAC:
       - Overview: rbac/roles.md
-  - Architecture: architecture.md
+  - Architecture: 
+      - Overview: architecture/architecture.md
+      - 2A initialisation process: architecture/initialisation.md
   - Glossary: glossary.md