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Kubernetes Multi-Cloud

1 - Approches Multi-Cluster​

1.1 Patterns​

PatternAvantagesInconvénients
FederationAbstraction native K8sComplexe, moins mature
Service MeshTraffic managementOverhead réseau
GitOpsSimple, déclaratifPas de routing cross-cluster

2 - Service Mesh avec Istio​

2.1 Architecture Multi-Cluster​

2.2 Installation Istio Multi-Cluster​

# Cluster 1 (AWS)
istioctl install --set profile=default \
    --set values.global.meshID=mesh1 \
    --set values.global.multiCluster.clusterName=cluster1 \
    --set values.global.network=network1

# Créer le remote secret pour cluster 2
istioctl x create-remote-secret --name=cluster1 > cluster1-secret.yaml

# Cluster 2 (Azure) - Appliquer le secret
kubectl apply -f cluster1-secret.yaml

# Cluster 2 - Installation
istioctl install --set profile=default \
    --set values.global.meshID=mesh1 \
    --set values.global.multiCluster.clusterName=cluster2 \
    --set values.global.network=network2

2.3 Service Entry Cross-Cluster​

# Exposer un service du cluster 1 au cluster 2
apiVersion: networking.istio.io/v1beta1
kind: ServiceEntry
metadata:
  name: external-api
spec:
  hosts:
    - api.cluster1.local
  location: MESH_INTERNAL
  ports:
    - number: 80
      name: http
      protocol: HTTP
  resolution: DNS
  endpoints:
    - address: api.cluster1.example.com
      ports:
        http: 80

3 - GitOps Multi-Cluster avec ArgoCD​

3.1 Architecture​

3.2 Ajouter des clusters à ArgoCD​

# Ajouter le cluster AWS
argocd cluster add aws-eks-production --name aws-prod

# Ajouter le cluster Azure
argocd cluster add azure-aks-production --name azure-prod

# Ajouter le cluster GCP
argocd cluster add gcp-gke-production --name gcp-prod

# Lister les clusters
argocd cluster list

3.3 ApplicationSet Multi-Cluster​

apiVersion: argoproj.io/v1alpha1
kind: ApplicationSet
metadata:
  name: my-app-multicloud
  namespace: argocd
spec:
  generators:
    - list:
        elements:
          - cluster: aws-prod
            url: https://eks.aws.example.com
            region: eu-west-1
          - cluster: azure-prod
            url: https://aks.azure.example.com
            region: westeurope
          - cluster: gcp-prod
            url: https://gke.gcp.example.com
            region: europe-west1
  template:
    metadata:
      name: 'my-app-{{cluster}}'
    spec:
      project: default
      source:
        repoURL: https://github.com/myorg/my-app.git
        targetRevision: main
        path: 'kubernetes/overlays/{{cluster}}'
      destination:
        server: '{{url}}'
        namespace: my-app
      syncPolicy:
        automated:
          prune: true
          selfHeal: true

4 - Rancher Multi-Cluster​

4.1 Installation​

# Installer Rancher avec Helm
helm repo add rancher-latest https://releases.rancher.com/server-charts/latest

helm install rancher rancher-latest/rancher \
    --namespace cattle-system \
    --create-namespace \
    --set hostname=rancher.example.com \
    --set replicas=3

4.2 Import de clusters​

# Via l'interface Rancher:
# 1. Cluster Management > Import Existing
# 2. Générer la commande kubectl
# 3. Exécuter sur le cluster cible

# Exemple de commande générée
kubectl apply -f https://rancher.example.com/v3/import/xxxxx.yaml

4.3 Fleet pour GitOps​

# fleet.yaml
defaultNamespace: my-app
helm:
  releaseName: my-app
  chart: ./charts/my-app
  values:
    replicaCount: 3

targetCustomizations:
  - name: aws-production
    clusterSelector:
      matchLabels:
        env: production
        cloud: aws
    helm:
      values:
        replicaCount: 5
        
  - name: azure-dr
    clusterSelector:
      matchLabels:
        env: dr
        cloud: azure
    helm:
      values:
        replicaCount: 2

5 - Karmada Federation​

5.1 Architecture​

5.2 PropagationPolicy​

apiVersion: policy.karmada.io/v1alpha1
kind: PropagationPolicy
metadata:
  name: my-app-propagation
spec:
  resourceSelectors:
    - apiVersion: apps/v1
      kind: Deployment
      name: my-app
  placement:
    clusterAffinity:
      clusterNames:
        - aws-cluster
        - azure-cluster
    replicaScheduling:
      replicaDivisionPreference: Weighted
      replicaSchedulingType: Divided
      weightPreference:
        staticWeightList:
          - targetCluster:
              clusterNames:
                - aws-cluster
            weight: 2
          - targetCluster:
              clusterNames:
                - azure-cluster
            weight: 1

6 - Traffic Global avec Submariner​

6.1 Connecter les clusters​

# Installer Submariner sur chaque cluster
subctl deploy-broker --kubeconfig /path/to/management/config

# Joindre les clusters
subctl join broker-info.subm --kubeconfig /path/to/aws-cluster \
    --clusterid aws-cluster

subctl join broker-info.subm --kubeconfig /path/to/azure-cluster \
    --clusterid azure-cluster

6.2 ServiceExport​

# Exporter un service pour le rendre accessible cross-cluster
apiVersion: multicluster.x-k8s.io/v1alpha1
kind: ServiceExport
metadata:
  name: my-service
  namespace: my-app

6.3 ServiceImport​

# Importer un service d'un autre cluster
apiVersion: multicluster.x-k8s.io/v1alpha1
kind: ServiceImport
metadata:
  name: my-service
  namespace: my-app
spec:
  type: ClusterSetIP
  ports:
    - port: 80
      protocol: TCP

7 - Configuration kubectl Multi-Context​

# Voir les contextes
kubectl config get-contexts

# Changer de contexte
kubectl config use-context aws-production

# Utiliser un contexte spécifique
kubectl --context=azure-dr get pods

# kubectx pour faciliter
kubectx aws-production

# Alias utiles dans .bashrc
alias kaws='kubectl --context=aws-production'
alias kazure='kubectl --context=azure-dr'
alias kgcp='kubectl --context=gcp-analytics'

Résumé​

Dans ce chapitre, nous avons appris :

  • Les approches multi-cluster
  • Istio Service Mesh multi-cluster
  • ArgoCD GitOps multi-cluster
  • Rancher et Fleet
  • Karmada Federation
  • Submariner pour le networking

Prochaine étape​

Dans le prochain chapitre, nous verrons le Networking Multi-Cloud.

→ Chapitre suivant : Networking Multi-Cloud

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