WIP: requirements

Author: silopolis

docs/project/requirements/architecture.md

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+# Architecture
+
+Un schéma d'implémentation détaillé sera établi pour décrire l'architecture globale de l'infrastructure, y compris les différents composants, leur interaction et leur déploiement.
+
+
+## Application
+
+
+### Proxy: Traefik
+
+* Application router
+* High-availability by fault tolerance
+* Load-balancing by requests distribution
+  ALB ?
+* Helm chart
+* Version
+
+
+### Application: FastAPI
+
+* Python
+  * Version:
+  * Packaging
+* Project management? Poetry?
+
+
+### Databases: PostgreSQL
+
+* Application is using the well known and battle-tested OSS PostgreSQL database management system.
+
+  FIXME pg version
+
+* Use a specialized Kubernetes operator to manage the PostgreSQL cluster
+
+  Zalando's **postgres-operator** is chosen because...
+  FIXME main reason(s) to choose it over alternatives
+
+  Alternative OSS solutions available are: ...
+  FIXME list alternative solution considered
+
+* Helm chart
+* Single read/write Master / Multi read-only slaves architectur
+
+  It provides both high availability and read load balancing, without the additional complexity of multi-master configuration, which the application doesn't require at the moment.
+
+* Master failover
+
+
+## Infrastructure
+
+
+### Network
+
+
+#### Application Load Balancer (ALB)
+
+
+#### Virtual Private Cloud (VPC)
+
+* VPC subnet
+
+
+#### Internet Gateways (IGW)
+
+* Global egress
+
+
+#### Availability Zones (AZ)
+
+* 3 availability zones for high availability
+
+
+#### NAT Gateways (NGW)
+
+* Per AZ egress
+* In public subnet
+
+
+#### Subnets
+
+
+##### Public subnets
+
+* Application access
+* Bastion access
+* NAT gateways ?
+
+
+##### Private subnets
+
+* Database
+* Admin
+
+
+### Compute
+
+#### Nodes
+
+* EC2 compute nodes
+  * Application nodes
+  * Database nodes
+  * Bastion node
+* Auto-scaling groups
+
+
+#### Orchestration: Kubernetes
+
+#### Pods
+
+##### ReplicaSets
+
+* Traefik
+* Application
+* Database
+* cert-manager
+* Metrics server
+* bastion
+
+##### DaemonSets
+
+* Any ?
+
+
+### Storage
+
+#### CSI
+
+##### EBS
+
+* For persistent storage needs (application data, logs, and monitoring metrics) AWS Elastic Block Storage (EBS) is used to provide persistent block devices to stateful pods
+* To integrate EBS with Kubernetes, the Container Storage Interface is leveraged by using the `aws-ebs-csi-driver` cluster addon from EKS which registers EBS volumes as a backend for K8s Persistant Volumes.
+
+
+
+## CI/CD
+
+### GitHub Actions
+
+
+#### Actions
+
+#### Workflows
+
+* Application
+* Infrastructure
+
+
+## Observability
+
+### Log management (ELK/EFK)
+
+### Metrics (Prometheus/Grafana)
+
+### Event and alerting
+
+
+## Business continuity & Disaster Recovery
+
+### TODO Recap HA features
+
+### Backup
+
+### Disaster Recovery