OpenStack Cinder Replication and Disaster Recovery, Pt. 4

This is part 4 of the series on OpenStack disaster recovery. Read Part 3: Revolutionizing Disaster Recovery with OpenStack: Project Aegis

Disaster Recovery Scenarios and Production Implementation

Real-World DR Scenarios: When Theory Meets Practice

Understanding disaster recovery concepts is one thing—implementing them effectively when systems are failing and business pressure is mounting is entirely different. Let’s explore specific disaster recovery scenarios and examine how the Project Aegis OpenStack-DR approach handles each situation with practical examples and realistic recovery objectives.

Remeber that Project Aegis is still in proof-of-concept phase and some of the Ansible playbooks named below are still in the development phase and may change name.

Scenario 1: Tenant-Specific Application Failover

The Situation: Your organization hosts multiple tenants in a single OpenStack cloud. Tenant 1’s critical e-commerce application experiences an application failure that requires immediate disaster recovery activation. Tenant 2 and Tenant 3 have applications running normally and cannot be disrupted.

Traditional Cinder Failover Impact:

Would require failing over the entire storage backend
All tenants’ applications would be affected
Non-replicated volumes would become unavailable
Requires coordinated maintenance window affecting all tenants
Recovery time: 2-4 hours including coordination and testing

OpenStack-DR Solution:

Step 1: Assessment and Preparation (2-3 minutes)

# Verify Protection Group status on Pure Storage
purepgroup list --snap tenant_1 # Confirm target cloud capacity openstack --os-cloud dr-site quota show --usage

Step 2: Individual Volume Promotion (1-2 minutes)

# Ansible playbook promotes specific volumes within tenant_1 Protection Group # This is handled automatically by the playbook, not manual commands # The playbook identifies and promotes individual volume copies

Step 3: Volume Import Execution (5-8 minutes)

# Execute tenant-specific Ansible playbook # This handles both volume promotion and import in a coordinated process
ansible-playbook -i inventory tenant_1_failover.yml

Step 4: Application Validation (2-5 minutes)

Verify imported volumes are accessible
Confirm instances started successfully for bootable volumes
Test application functionality
Update load balancer/DNS configurations

Results:

Total Recovery Time: 10-15 minutes
Recovery Point: Last Protection Group snapshot (typically <15 minutes data loss)
Impact on Other Tenants: Zero – Tenant 2 and Tenant 3 operations continue normally
Non-Replicated Volume Impact: None – all non-replicated storage remains accessible

Scenario 2: Multi-Tenant Data Center Failure

The Situation: The primary data center experiences a complete power outage affecting all infrastructure. All tenants require failover to the disaster recovery site.

OpenStack-DR Advantage: Even in a complete site failure, the granular approach provides benefits through parallel processing and selective recovery prioritization.

Recovery Strategy:

Phase 1: Critical Applications (0-15 minutes)

Identify and prioritize mission-critical tenant applications
Execute Ansible playbooks to promote individual volumes within critical tenants’ Protection Groups
Import promoted individual volumes for highest-priority applications

Phase 2: Standard Applications (15-30 minutes)

Continue processing remaining tenant applications in priority order
Promote and import individual volumes for standard applications
Monitor capacity and performance on DR site during parallel operations

Phase 3: Validation and Optimization (30-45 minutes)

Comprehensive application testing across all recovered tenants
Network configuration updates and traffic redirection
Performance monitoring and optimization

Benefits Over Traditional Approach:

Prioritized Recovery: Critical applications recovered first
Parallel Processing: Multiple tenant recoveries can run simultaneously
Resource Management: DR site resources allocated based on priority
Granular Monitoring: Recovery progress tracked per tenant/application

Scenario 3: Synchronous Replication for Zero Data Loss

The Situation: A financial services tenant requires zero data loss protection for regulatory compliance. Their trading application cannot tolerate any data loss during disaster recovery operations.

Configuration Requirements:

[fa_financial_sync] volume_backend_name = fa_financial_sync volume_driver = cinder.volume.drivers.pure.PureISCSIDriver san_ip = <FA_PRIMARY_MGMT_IP> replication_device = backend_id:fa-dr,san_ip:<FA_DR_MGMT_IP>,api_token:<FA_DR_TOKEN>,type:sync pure_api_token = <FA_PRIMARY_TOKEN> pure_replication_pod_name = financial_pod

DR Execution Process:

Application Quiescing: Gracefully shutdown trading application to ensure data consistency
Stretched Pod Management: Pure Storage ActiveCluster handles synchronous replication automatically
Volume Import: Import promoted volumes with zero data loss guarantee
Application Restart: Start trading application on DR site with complete data integrity

Recovery Characteristics:

Recovery Point Objective (RPO): 0 (zero data loss)
Recovery Time Objective (RTO): 5-10 minutes including application quiescing
Compliance: Meets regulatory requirements for financial trading systems

Production Implementation Best Practices

Multi-Backend Design Strategy

Plan your backend architecture to maximize operational flexibility:

# Production-ready multi-tenant configuration [DEFAULT] enabled_backends = finance_sync, ecommerce_async, development_local, analytics_async [finance_sync] # Zero data loss for financial applications pure_replication_pod_name = finance_pod replication_device = type:sync [ecommerce_async] # Performance-optimized for web applications pure_replica_interval_default = 300 # 5 minutes replication_device = type:async [development_local] # Development environment without replication # No replication_device configuration [analytics_async] # Long-term data protection for analytics pure_replica_interval_default = 3600 # 1 hour pure_replica_retention_long_term_default = 30 # 30 days replication_device = type:async

Volume Type Management

Create a comprehensive volume type strategy:

# Financial services - zero data loss
openstack volume type create Financial_ZeroLoss openstack volume type set --property volume_backend_name=finance_sync Financial_ZeroLoss openstack volume type set --property replication_enabled='<is> True' Financial_ZeroLoss openstack volume type set --property replication_type='<in> sync' Financial_ZeroLoss

# E-commerce - performance optimized
openstack volume type create Ecommerce_Performance openstack volume type set --property volume_backend_name=ecommerce_async Ecommerce_Performance openstack volume type set --property replication_enabled='<is> True' Ecommerce_Performance openstack volume type set --property replication_type='<in> async' Ecommerce_Performance

# Development - local only
openstack volume type create Development_Local openstack volume type set --property volume_backend_name=development_local Development_Local

Ansible Playbook Structure

Organize your automation for maximum flexibility:

# tenant_recovery_master.yml - name: Multi-tenant disaster recovery orchestration hosts: localhost vars: recovery_priority: critical: [finance, ecommerce_prod] standard: [ecommerce_staging, analytics] development: [dev_tenant_1, dev_tenant_2] tasks: - name: Execute critical application recovery include_tasks: single_tenant_recovery.yml loop: "{{ recovery_priority.critical }}" loop_control: loop_var: tenant_name

Monitoring and Alerting

Implement comprehensive monitoring for replication health:

Protection Group and Pod Status: Monitor replication lag and failure conditions
Volume Import Success: Track automated recovery operations
Application Health: Validate recovered applications functionality
Capacity Utilization: Monitor DR site resource consumption

Testing and Validation Framework

Regular DR Testing Strategy:

Monthly: Individual tenant failover testing during maintenance windows
Quarterly: Partial data center simulation with multiple tenants
Annually: Complete disaster recovery exercise including all systems

Automated Testing Integration:

# Automated DR test execution
./scripts/dr_test.sh --tenant finance --validate-only --no-production-impact ./scripts/dr_test.sh --tenant ecommerce --partial-failover --test-duration 2h

In my next post, I’ll address the operational considerations that make DR work sustainably in production, explore advanced configuration patterns, and examine the future roadmap for OpenStack disaster recovery technologies.