Disaster Recovery

Multi-Cloud DR Strategy

Cross-Region Replication

resource "aws_s3_bucket" "dr_bucket" {
  bucket = "my-dr-bucket"
  
  versioning {
    enabled = true
  }
  
  replication_configuration {
    role = aws_iam_role.replication.arn
    
    rules {
      id     = "dr-replication"
      status = "Enabled"
      
      destination {
        bucket = aws_s3_bucket.destination.arn
        storage_class = "STANDARD"
      }
    }
  }
}

resource "azurerm_storage_account" "dr_storage" {
  name                     = "drstorage"
  resource_group_name      = azurerm_resource_group.dr.name
  location                 = var.dr_location
  account_tier             = "Standard"
  account_replication_type = "GRS"
  
  geo_redundant_backup_enabled = true
}

Automated Failover

Kubernetes DR Controller

apiVersion: apps/v1
kind: Deployment
metadata:
  name: dr-controller
spec:
  replicas: 1
  selector:
    matchLabels:
      app: dr-controller
  template:
    spec:
      containers:
      - name: controller
        image: dr-controller:latest
        env:
        - name: PRIMARY_CLUSTER
          value: "us-west-2"
        - name: DR_CLUSTER
          value: "eu-west-1"
        - name: HEALTH_CHECK_INTERVAL
          value: "30"
        - name: FAILOVER_THRESHOLD
          value: "3"

Health Monitoring

Synthetic Monitoring

apiVersion: monitoring.googleapis.com/v1
kind: UptimeCheckConfig
metadata:
  name: dr-health-check
spec:
  displayName: "DR Health Check"
  period: "60s"
  timeout: "10s"
  httpCheck:
    path: "/health"
    port: 443
  monitoredResource:
    type: "uptime_url"
    labels:
      host: "primary-endpoint.example.com"
  alertPolicy:
    name: "projects/my-project/alertPolicies/dr-failover"

Data Consistency

Database Replication

apiVersion: postgresql.acid.zalan.do/v1
kind: PostgresqlCluster
metadata:
  name: postgres-dr
spec:
  numberOfInstances: 3
  patroni:
    synchronous_mode: true
    synchronous_node_count: 2
  postgresql:
    version: "15"
    parameters:
      synchronous_commit: "on"
      max_wal_senders: "10"
      wal_keep_segments: "64"
  volumes:
    data:
      size: 100Gi
      storageClass: "premium-rwo"
  standby:
    enabled: true
    s3:
      bucket: "postgres-wal"
      region: "eu-west-1"

Best Practices

1. RPO/RTO Planning

   • Recovery objectives

   • Data consistency

   • Service priorities

   • Failback procedures

2. Testing Strategy

   • Regular DR drills

   • Automated testing

   • Performance validation

   • Documentation updates

3. Monitoring

   • Health checks

   • Replication status

   • Failover metrics

   • Cost tracking

4. Documentation

   • Runbooks

   • Contact lists

   • Recovery procedures

   • Lessons learned