Disaster Recovery with a Digital Twin

From static DR plans to a proactive, model-driven recovery strategy.

From DR Plans to a Living DR Blueprint with rescile

Disaster Recovery (DR) in a hybrid cloud is a practice fraught with complexity. Traditional DR plans, often captured in static documents, are difficult to maintain, test, and audit. They quickly become disconnected from the reality of a constantly changing infrastructure, leaving businesses vulnerable when a disaster strikes. The key challenges are not just in planning but in ensuring the plan is accurate, compliant, and executable.

rescile addresses this by transforming your DR strategy from a static document into a living blueprint—a Digital Twin of your entire hybrid environment. This queryable dependency graph connects every technical asset to its business context, its dependencies, and its governing policies. By modeling your DR plan as code, you can move from reactive, manual recovery to proactive, automated, and continuously compliant resilience.

This document outlines how to use rescile to implement DR best practices not as a checklist, but as an executable model.

1. From Business Impact Analysis (BIA) to a Queryable Blueprint

Best Practice: Define Recovery Time Objectives (RTOs) and Recovery Point Objectives (RPOs) based on a thorough risk assessment and Business Impact Analysis.

The traditional BIA is a manual, interview-heavy process that results in a spreadsheet. This is impossible to keep current. With rescile, your BIA becomes a query. The dependency graph provides the data to answer critical questions instantly:

  • Blast Radius: “If our primary database goes down, which applications and business services are impacted?”
  • Criticality Mapping: “Show me all infrastructure components supporting our ‘Tier 1’ applications.”
  • Dependency Verification: “Does our ‘billing-api’ have a dependency on a non-replicated, single-region service?”

By modeling these relationships, rescile provides a definitive, always-current foundation for setting RTOs and RPOs, turning your BIA from a periodic snapshot into a real-time tool.

2. Modeling and Enforcing the DR Plan as Code

Best Practice: Define and enforce DR policies, including geographic redundancy, and align them with regulatory requirements like GDPR, HIPAA, or PCI DSS.

With rescile, your DR plan and its requirements are not just text in a document; they are resources and rules within the graph itself. This allows for automated, continuous validation.

First, you model your DR components as first-class citizens. For example, you can define dr_plan and dr_site resources:

data/assets/dr_site.csv

name,region,provider
dr-site-ireland,eu-west-1,aws
dr-site-virginia,us-east-1,aws

data/assets/dr_plan.csv

name,application,dr_site,rto_hours,rpo_minutes
plan-billing-api,billing-api,dr-site-ireland,2,15

data/assets/application.csv

name,tier,database
billing-api,1,billing-db-prod

data/assets/database.csv

name,failover_target
billing-db-prod,billing-db-dr
billing-db-dr,

With this model in place, you can write a compliance/*.toml file to automatically enforce that your most critical applications adhere to the plan.

# data/compliance/resilience.toml
audit_id = "APP-RESILIENCE-01"
audit_name = "App Resilience 01"

[[control]]
id = "TIER1-DR-PLAN-ENFORCEMENT"
name = "Tier 1 applications must have an approved DR plan targeting a valid DR site"

[[control.target]]
# 1. Find all Tier 1 applications
origin_resource_type = "application"
match_on = [{ property = "tier", value = "1" }]

# 2. Find the 'dr_plan' resource linked to this application.
#    The rule will fail for any Tier 1 app where this link does not exist
#    or the conditions on the plan are not met.
[control.target.resource]
type = "dr_plan"
match_on = [
    # The plan must have an RTO of 4 hours or less.
    { property = "rto_hours", lower = 4.01 },
    # The plan must target a valid, existing DR site.
    { property = "dr_site", exists = true }
]

# 3. Link this control to the application, creating auditable evidence.
#    You can now query for applications NOT VALIDATED_BY this control
#    to instantly find compliance gaps.
[control.target.relation]
type = "VALIDATED_BY"

This turns your DR policy from a statement in a document into a testable, verifiable, and continuously enforced assertion on your live infrastructure model.

3. Blueprint-Driven Recovery Automation

Best Practice: Leverage automation and Infrastructure-as-Code (IaC) to speed up recovery and reduce human error.

rescile serves as the single source of truth for generating all artifacts needed for recovery, guaranteeing consistency and eliminating configuration drift between primary and DR environments.

3.1. Generating IaC for Stateful Recovery

A common failure point is a mismatch between the primary and DR environments. rescile prevents this by generating IaC configurations directly from the blueprint. Instead of maintaining separate Terraform files for your DR site, you model the failover environment as part of your blueprint and use rescile to generate the terraform.tfvars.json or other artifacts needed to deploy it.

  • Consistency Guaranteed: The failover environment is built from the same model as the primary, ensuring it’s an accurate, up-to-date replica.
  • Configuration on Demand: During a DR event, you generate the IaC configuration from the current, approved blueprint. No more stale recovery scripts.
  • Reduced Manual Error: Automating the generation of IaC variables eliminates typos or misconfigurations during a high-stress recovery.

3.2. Generating Executable Runbooks for Imperative Steps

DR activation often involves more than just declarative IaC. Many critical steps are imperative actions, such as failing over a database, updating a DNS record, or triggering a notification. These non-stateful commands are difficult to manage with tools like Terraform alone.

rescile’s powerful templating engine can generate any text-based artifact, including executable shell scripts that act as dynamic runbooks.

For example, you can create a data/output/dr_failover_script.toml file to generate a failover script for your database:

# data/output/dr_failover_script.toml
origin_resource = "application"

[[output]]
resource_type = "dr_runbook"
name = "failover-script-for-{{ origin_resource.name }}.sh"
match_on = [{ property = "tier", value = "1" }]

# This Tera template renders a shell script using data from the graph.
template = """
#!/bin/bash
# Auto-generated DR failover script for {{ origin_resource.name }}
set -e

DB_CLUSTER_ID="{{ origin_resource.database[0].name }}"
# Assumes the DR database is modeled with a 'failover_target' relation
FAILOVER_TARGET_ID="{{ origin_resource.database[0].failover_target }}"

echo "--- Initiating failover for RDS cluster: ${DB_CLUSTER_ID} ---"
echo "Target instance: ${FAILOVER_TARGET_ID}"

aws rds failover-db-cluster \
  --db-cluster-identifier "${DB_CLUSTER_ID}" \
  --target-db-instance-identifier "${FAILOVER_TARGET_ID}"

echo "✅ Failover initiated successfully."
"""

This approach combines the declarative power of IaC with the procedural control needed for a complete recovery, all generated from a single, unified blueprint.

4. Verifying Recovery and Automating Evidence

Best Practice: Regularly test your DR plan to validate its effectiveness and familiarize stakeholders with the process.

Testing is often the most neglected part of DR. rescile makes it easier by providing definitive lists and a method for verification.

  • Definitive Failover/Failback Lists: A simple query against the rescile graph can provide a complete, machine-readable “bill of materials” for any application. This serves as the definitive checklist for what needs to be failed over and, just as importantly, what needs to be cleaned up during failback to prevent costly orphaned resources.

    # Find all dependencies for the 'billing-api' application
query GetApplicationDependencies {
  application(filter: {name: {eq: "billing-api"}}) {
    name
    server { node { name } }
    database { node { name } }
    # ... all other connected resources
  }
}

  • Automated Test Validation: After a DR test, you can use an importer to ingest the actual state of the recovery environment into rescile. By running a diff between the “as-built” state and the “as-designed” blueprint, you can automatically verify that the recovery was successful and compliant, generating an auditable report as evidence of a successful test.

Conclusion: DR with Confidence

By leveraging a Digital Twin, rescile elevates Disaster Recovery from a reactive, documentation-based exercise to a proactive, model-driven discipline. Your DR plan becomes a living, testable, and enforceable part of your architecture. This allows you to build, verify, and execute your recovery strategy with a level of confidence and auditability that static documents and manual processes can never achieve.