AWS DevOps Infrastructure Code : les 9 étapes clés pour passer de zéro à opérationnel

from aws_cdk import aws_s3 as s3
import aws_cdk as cdk

class MaStack(cdk.Stack):
    def __init__(self, scope, id, **kwargs):
        super().__init__(scope, id, **kwargs)

        # L1 : CfnBucket = wrapper direct CloudFormation AWS::S3::Bucket
        bucket_l1 = s3.CfnBucket(self, "BucketL1",
            bucket_name="mon-bucket-l1",
            versioning_configuration=s3.CfnBucket.VersioningConfigurationProperty(
                status="Enabled"
            ),
            lifecycle_configuration=s3.CfnBucket.LifecycleConfigurationProperty(
                rules=[s3.CfnBucket.RuleProperty(
                    id="expiration-anciens-objets",
                    status="Enabled",
                    expiration_in_days=90
                )]
            )
        )

infrastructure/
├── stack-parent.yaml         # Stack racine — orchestre tout
├── modules/
│   ├── reseau.yaml           # VPC, subnets, Internet Gateway
│   ├── securite.yaml         # Security Groups, IAM Roles
│   ├── base-de-donnees.yaml  # RDS, cache ElastiCache
│   └── application.yaml      # EC2, Load Balancer, Auto Scaling

AWSTemplateFormatVersion: "2010-09-09"
Description: "Stack parent — orchestre toute l'infrastructure"

Parameters:
  Environnement:
    Type: String
    AllowedValues: [dev, prod]
  URLTemplates:
    Type: String
    Description: "URL S3 de base où sont stockés les templates"
    Default: "https://s3.amazonaws.com/mon-bucket-templates/v1"

Resources:
  # Module réseau
  StackReseau:
    Type: AWS::CloudFormation::Stack
    Properties:
      TemplateURL: !Sub "${URLTemplates}/reseau.yaml"
      Parameters:
        Environnement: !Ref Environnement
        CIDRVpc: "10.0.0.0/16"
      TimeoutInMinutes: 15

  # Module sécurité — dépend du réseau
  StackSecurite:
    Type: AWS::CloudFormation::Stack
    DependsOn: StackReseau
    Properties:
      TemplateURL: !Sub "${URLTemplates}/securite.yaml"
      Parameters:
        Environnement: !Ref Environnement
        VpcId: !GetAtt StackReseau.Outputs.VpcId

  # Module base de données
  StackBDD:
    Type: AWS::CloudFormation::Stack
    DependsOn: StackSecurite
    Properties:
      TemplateURL: !Sub "${URLTemplates}/base-de-donnees.yaml"
      Parameters:
        Environnement: !Ref Environnement
        VpcId: !GetAtt StackReseau.Outputs.VpcId
        SubnetIds: !GetAtt StackReseau.Outputs.SubnetsPrives
        SGBaseDeDonnees: !GetAtt StackSecurite.Outputs.SGBaseDeDonnees
      TimeoutInMinutes: 30

  # Module application
  StackApplication:
    Type: AWS::CloudFormation::Stack
    DependsOn: StackBDD
    Properties:
      TemplateURL: !Sub "${URLTemplates}/application.yaml"
      Parameters:
        Environnement: !Ref Environnement
        VpcId: !GetAtt StackReseau.Outputs.VpcId
        SubnetPublics: !GetAtt StackReseau.Outputs.SubnetsPublics
        URLBDD: !GetAtt StackBDD.Outputs.EndpointBDD
        SGApplication: !GetAtt StackSecurite.Outputs.SGApplication

Outputs:
  URLApplication:
    Description: "URL du Load Balancer de l'application"
    Value: !GetAtt StackApplication.Outputs.URLLoadBalancer

AWSTemplateFormatVersion: "2010-09-09"
Description: "Module réseau — VPC, subnets publics et privés"

Parameters:
  Environnement:
    Type: String
  CIDRVpc:
    Type: String

Resources:
  VPC:
    Type: AWS::EC2::VPC
    Properties:
      CidrBlock: !Ref CIDRVpc
      EnableDnsHostnames: true
      EnableDnsSupport: true
      Tags:
        - Key: Name
          Value: !Sub "vpc-${Environnement}"

  SubnetPublic1:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref VPC
      CidrBlock: "10.0.1.0/24"
      AvailabilityZone: !Select [0, !GetAZs ""]
      MapPublicIpOnLaunch: true

  SubnetPrive1:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref VPC
      CidrBlock: "10.0.10.0/24"
      AvailabilityZone: !Select [0, !GetAZs ""]

Outputs:
  VpcId:
    Value: !Ref VPC
    Export:
      Name: !Sub "${AWS::StackName}-VpcId"
  SubnetsPublics:
    Value: !Join [",", [!Ref SubnetPublic1]]
    Export:
      Name: !Sub "${AWS::StackName}-SubnetsPublics"
  SubnetsPrives:
    Value: !Join [",", [!Ref SubnetPrive1]]
    Export:
      Name: !Sub "${AWS::StackName}-SubnetsPrives"

apiVersion: apps/v1
kind: Deployment
metadata:
  name: mon-api-fastapi
  namespace: mon-application
  labels:
    app: mon-api-fastapi
    version: "1.0.0"
    equipe: backend
spec:
  replicas: 3
  selector:
    matchLabels:
      app: mon-api-fastapi
  # Stratégie de déploiement rolling update
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 1      # Au plus 1 Pod indisponible pendant la mise à jour
      maxSurge: 1            # Au plus 1 Pod en surplus pendant la mise à jour
  template:
    metadata:
      labels:
        app: mon-api-fastapi
        version: "1.0.0"
    spec:
      serviceAccountName: sa-mon-api  # IRSA — IAM Role for Service Account
      terminationGracePeriodSeconds: 30
      # Sécurité au niveau du Pod
      securityContext:
        runAsNonRoot: true
        runAsUser: 1000
        fsGroup: 1000
      containers:
        - name: mon-api-fastapi
          image: 123456789012.dkr.ecr.ca-central-1.amazonaws.com/mon-api-fastapi:1.0.0
          ports:
            - containerPort: 8080
              protocol: TCP
          # Limites de ressources obligatoires en production
          resources:
            requests:
              cpu: "250m"        # 0.25 vCPU garanti
              memory: "256Mi"    # 256 Mo garantis
            limits:
              cpu: "500m"        # Maximum 0.5 vCPU
              memory: "512Mi"    # Maximum 512 Mo
          # Variables d'environnement depuis ConfigMap et Secret
          env:
            - name: ENVIRONNEMENT
              value: production
            - name: PORT
              value: "8080"
          envFrom:
            - configMapRef:
                name: config-mon-api
            - secretRef:
                name: secrets-mon-api
          # Sondes de santé
          livenessProbe:
            httpGet:
              path: /health
              port: 8080
            initialDelaySeconds: 15
            periodSeconds: 20
            failureThreshold: 3
          readinessProbe:
            httpGet:
              path: /health
              port: 8080
            initialDelaySeconds: 5
            periodSeconds: 10
            successThreshold: 1
          startupProbe:
            httpGet:
              path: /health
              port: 8080
            failureThreshold: 30
            periodSeconds: 5
          # Sécurité du conteneur
          securityContext:
            allowPrivilegeEscalation: false
            readOnlyRootFilesystem: true
            capabilities:
              drop:
                - ALL
      # Distribution entre les zones de disponibilité
      topologySpreadConstraints:
        - maxSkew: 1
          topologyKey: topology.kubernetes.io/zone
          whenUnsatisfiable: DoNotSchedule
          labelSelector:
            matchLabels:
              app: mon-api-fastapi

---
# Service ClusterIP — pour la communication interne
apiVersion: v1
kind: Service
metadata:
  name: svc-mon-api
  namespace: mon-application
  labels:
    app: mon-api-fastapi
spec:
  type: ClusterIP
  selector:
    app: mon-api-fastapi      # Correspond aux labels du Deployment
  ports:
    - name: http
      port: 80                # Port du Service (interne)
      targetPort: 8080        # Port du conteneur
      protocol: TCP

---
# Service LoadBalancer — expose via un NLB AWS
apiVersion: v1
kind: Service
metadata:
  name: svc-mon-api-public
  namespace: mon-application
  annotations:
    service.beta.kubernetes.io/aws-load-balancer-type: "external"
    service.beta.kubernetes.io/aws-load-balancer-nlb-target-type: "ip"
    service.beta.kubernetes.io/aws-load-balancer-scheme: "internet-facing"
spec:
  type: LoadBalancer
  selector:
    app: mon-api-fastapi
  ports:
    - name: http
      port: 80
      targetPort: 8080

apiVersion: v1
kind: ConfigMap
metadata:
  name: config-mon-api
  namespace: mon-application
data:
  # Variables d'environnement
  LOG_LEVEL: "info"
  WORKERS: "4"
  TIMEOUT: "30"
  DATABASE_HOST: "rds-mon-app.ca-central-1.rds.amazonaws.com"
  DATABASE_NAME: "production"
  # Fichier de configuration complet
  application.yaml: |
    server:
      host: 0.0.0.0
      port: 8080
    database:
      pool_size: 10
      max_overflow: 5
    cache:
      backend: redis
      ttl: 300

apiVersion: v1
kind: Secret
metadata:
  name: secrets-mon-api
  namespace: mon-application
type: Opaque
stringData:
  # stringData accepte les valeurs en clair — K8s les encode en base64 automatiquement
  DATABASE_PASSWORD: "MonMotDePasseSecret"
  API_KEY: "sk-abc123..."
  JWT_SECRET: "ma-cle-jwt-super-secrete"

apiVersion: external-secrets.io/v1beta1
kind: ExternalSecret
metadata:
  name: secrets-aws-synchronises
  namespace: mon-application
spec:
  refreshInterval: 1h
  secretStoreRef:
    name: aws-secrets-manager
    kind: ClusterSecretStore
  target:
    name: secrets-mon-api   # Nom du Secret Kubernetes à créer
    creationPolicy: Owner
  data:
    - secretKey: DATABASE_PASSWORD
      remoteRef:
        key: "mon-app/production/secrets"
        property: "database_password"
    - secretKey: API_KEY
      remoteRef:
        key: "mon-app/production/secrets"
        property: "api_key"