Disaster Recovery Plan Aws Template

Standard Operating Procedure: AWS Multi-Region Disaster Recovery Architecture & Execution

Document ID: SOP-AWS-DR-9042
Effective Date: October 24, 2023
Version: 4.2.0
Review Cadence: Semi-Annual
Author: Julian Vance, Chief Architect, Template Registry

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1. Document Control Block

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2. Executive Summary & Purpose

This Standard Operating Procedure (SOP) defines the institutional blueprint, engineering controls, and automated deployment templates required to execute Disaster Recovery (DR) operations within Amazon Web Services (AWS). The objective of this document is to ensure a standardized, repeatable, and auditable methodology for spinning up, validating, and failing over mission-critical infrastructure from a primary operational region (e.g., us-east-1) to a designated secondary recovery region (e.g., us-west-2).

This SOP utilizes Infrastructure as Code (IaC) via AWS CloudFormation/Terraform templates to enforce Recovery Point Objectives (RPO) of $< 15$ minutes and Recovery Time Objectives (RTO) of $< 30$ minutes across all Tier-0 microservices.

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3. Scope & Prerequisites

3.1 Scope

• In-Scope: AWS-hosted compute (EKS, EC2), storage (S3, EBS, EFS), relational databases (Aurora Global Database), networking (Route 53, VPC, Transit Gateway), and identity management (IAM).
• Out-of-Scope: On-premises data center failovers, third-party SaaS endpoint configurations managed outside AWS, and client-side DNS caching layers.

3.2 Prerequisites & Tooling

• Access Control: AWS Administrator Access or equivalent cross-account IAM role assumption (arn:aws:iam::ACCOUNT_ID:role/DR-Master-Execution-Role).
• Software Dependencies:
  • Terraform v1.5.x or AWS CLI v2.13+ installed locally or within the deployment runner.
  • jq (v1.6+) for JSON parsing in automation scripts.
  • aws-vault for secure credential management.
• Artifacts:
  • Validated AWS CloudFormation DR template or Terraform module (/templates/aws-dr-core-v4.2.tf).
  • Read-only access tokens for external monitoring platforms (Datadog, PagerDuty).

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4. Roles & Responsibilities

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5. Step-by-Step Procedure

Phase 1: Pre-Flight Verification & State Assessment

• 1.1 Authenticate with the AWS Management Console via aws-vault using MFA-secured credentials.
• 1.2 Verify current status of primary region replication pipelines via CloudWatch metrics:

  aws cloudwatch get-metric-data --metric-data-queries file://queries/replication-lag.json
  

• 1.3 Confirm that the Aurora Global Database replication lag is $< 1000$ milliseconds.
• 1.4 Validate that daily automated S3 Cross-Region Replication (CRR) sync reports show zero failure deltas.
• 1.5 Notify downstream consumers and executive stakeholders via PagerDuty/Slack emergency channels regarding DR status check initialization.

Phase 2: Execution of AWS DR Infrastructure Template

• 2.1 Navigate to the infrastructure repository root directory containing the disaster recovery templates.
• 2.2 Initialize the Terraform workspace for the recovery region:

  terraform workspace select dr-us-west-2 || terraform workspace new dr-us-west-2
  

• 2.3 Run a dry-run execution plan to verify resource provisioning integrity without state modification:

  terraform plan -var-file="config/prod-dr.tfvars" -out=tfplan.binary
  

• 2.4 Review the execution plan output to ensure zero unexpected resource destructions (destroy: 0).
• 2.5 Apply the infrastructure template to instantiate networking, security groups, and standby compute clusters in the recovery region:

  terraform apply tfplan.binary
  

• 2.6 Validate successful cluster bootstrap by executing health check endpoints against the newly provisioned Application Load Balancers (ALB).

Phase 3: Database Promotion & Data Integrity Validation

• 3.1 Initiate the forced failover of the Aurora Global Database cluster to promote the secondary region writer instance:

  aws rds failover-db-cluster \
      --db-cluster-identifier prod-global-db \
      --target-db-instance-identifier prod-instance-us-west-2-writer \
      --region us-west-2
  

• 3.2 Poll the RDS cluster status until the promoted instance state returns available and the role switches from secondary to writer.
• 3.3 Execute automated database schema validation and row-count checksum scripts against the promoted cluster:

  ./scripts/validate-db-checksums.sh --env production --region us-west-2
  

• 3.4 Confirm read/write traffic stabilization by querying the application audit logs.

Phase 4: Traffic Cutover & DNS Routing Modification

• 4.1 Update Route 53 latency-based or failover routing policies to shift 100% of incoming production traffic to the recovery region ALB:

  aws route53 change-resource-record-sets \
      --hosted-zone-id Z1234567890ABC \
      --change-batch file://dns/failover-to-west.json
  

• 4.2 Purge CloudFront distribution edge caches to clear stale routing tables:

  aws cloudfront create-invalidation --distribution-id E1234567890 --paths "/*"
  

• 4.3 Verify external public resolution using synthetic probes:

  dig +short api.template-registry.internal @8.8.8.8
  

Phase 5: Post-Failover Verification & Hand-off

• 5.1 Monitor Datadog APM dashboards for error rate spikes ($HTTP 5xx > 0.1%$).
• 5.2 Validate that auto-scaling groups (ASGs) in the recovery region dynamically scale to match historical peak load metrics.
• 5.3 Formalize system stability by issuing an incident closure update in the master incident management system.
• 5.4 Schedule a post-mortem engineering review within 48 hours of execution completion.

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6. Quality Assurance & Pro-Tips

6.1 Best Practices

• Immutable State Files: Store Terraform state files in a dedicated, version-controlled S3 bucket with DynamoDB state locking enabled to prevent concurrent conflicting runs.
• Regular Drills: Execute simulated DR failovers in a staging environment bi-annually to validate template drift and catch deprecations in AWS API services.
• Secrets Management: Reference dynamic credentials via AWS Secrets Manager or Parameter Store rather than hardcoding secrets into the DR templates.

6.2 Common Pitfalls

• Service Quotas: Failing to pre-request AWS service limit increases in the recovery region for EC2 vCPUs or Elastic IPs, resulting in deployment blockages during execution.
• Route 53 TTL Mismanagement: High Time-To-Live (TTL) values set on primary DNS records will drastically delay traffic migration times, violating RTO thresholds. Ensure production TTLs are kept at $\le 60$ seconds.

6.3 Metric Thresholds

• RPO Threshold: $\le 15$ Minutes (Maximum tolerated data loss window).
• RTO Threshold: $\le 30$ Minutes (Maximum tolerated downtime window).
• Error Budget Impact: $\le 0.05%$ aggregate drop in availability during cutover.

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7. Frequently Asked Questions

Q1: What happens if the Aurora database failover command hangs during Phase 3?
A: If the manual cluster promotion hangs for $> 5$ minutes, inspect the AWS RDS console for replication lock states. Force-detach the global database cluster association using the AWS CLI (aws rds remove-from-global-cluster), promote the secondary cluster independently, and immediately engage AWS Enterprise Support via a Severity-1 ticket.

Q2: How do we handle regional discrepancies in AWS resource availability (e.g., specific EC2 instance types missing in the DR region)?
A: The CloudFormation and Terraform templates incorporate instance-type fallback mapping logic (instance_type_map = { us-east-1 = "c6i.4xlarge", us-west-2 = "c5.4xlarge" }). Always reference the fallback mapping dictionary in the variables file rather than hardcoding distinct instance families.