Proposal for integration with PromOp CRDs

docs/proposals/promopcrds.md

@@ -0,0 +1,39 @@
+---
+title: "Cortex AlertmanagerConfig and PrometheusRule CRD Integration"
+linkTitle: "AlertmanagerConfig and PrometheusRule CRD Integration"
+weight: 20
+slug: alertmanagerconfig-prometheusrules-crd-integration
+---
+
+## Summary
+
+This proposal explores the idea of enabling Cortex Alertmanager to read and integrate with PrometheusOperator CRD AlertmanagerConfig and PrometheusRule resources. The goal is to bridge the gap between Kubernetes-native alerting configuration management and Cortex's multi-tenant architecture, allowing users to manage both alerting rules and notification configurations using familiar Kubernetes resources.
+
+## Problem Statement
+
+Currently, Cortex Alertmanager configuration can be managed through:
+1. Direct HTTP API calls to set/update configurations and rules (when enabled)
+2. Command-line tool for configuration management (cortextool)
+3. Manual change of the persisent storage
+4. I might be missing somehting?
+
+While these methods work, they have several limitations:
+- No Kubernetes-native experience - Users familiar with PrometheusOperator cannot leverage their existing knowledge
+- Manual configuration management - No automatic synchronization with Kubernetes resources
+- Limited GitOps integration - Cannot use standard Kubernetes deployment pipelines
+- Complex multi-tenant setup - Each tenant must manually manage their Alertmanager configuration and rules
+
+## The Idea
+
+What if Cortex could automatically read AlertmanagerConfig and PrometheusRule CRDs from user namespaces and integrate them into its multi-tenant Alertmanager system?
+
+## Approaches Considered
+
+### Option 1: Direct S3 Integration
+Create a component in each user namespace that watches local CRDs and writes directly to the bucket storage that Cortex Alertmanager uses.
+
+### Option 2: API Gateway Approach
+Create a component in each user namespace that reads local CRDs and translates them to API calls to Cortex Alertmanager.
+
+### Option 3: Two-Component Architecture
+Deploy an operator in the user cluster that reads CRDs across all namespaces, and an aggregator in the Cortex namespace that receives and processes the configurations.