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Use Case: Disaster Recovery

Business Context

Disaster recovery is a crucial aspect of business continuity, ensuring that workloads can be swiftly restored following catastrophic events. This use case outlines strategies and tools for implementing effective disaster recovery plans within the RH OVE ecosystem.

Technical Requirements

Infrastructure Requirements

  • OpenShift 4.12+ clusters with multi-cluster management enabled
  • Cross-cluster networking with VPN or direct connectivity
  • Data replication and backup solutions
  • Disaster recovery orchestration tools (Red Hat Advanced Cluster Management - RHACM)

Resource Requirements

  • Compute: Sufficient capacity on recovery clusters
  • Storage: Redundant storage solutions with replication
  • Network: Reliable, high-speed connections between primary and secondary sites

Architecture Overview

graph TD
    subgraph "Primary Cluster"
        VM1["VM 1"]
        VM2["VM 2"]
        PRIMARY_STORAGE["Primary Storage"]
    end

    subgraph "Disaster Recovery Cluster"
        DR_VM1["DR VM 1"]
        DR_VM2["DR VM 2"]
        DR_STORAGE["DR Storage"]
    end

    PRIMARY_STORAGE -- Replication --> DR_STORAGE
    VM1 -- Synchronization --> DR_VM1
    VM2 -- Synchronization --> DR_VM2

    style PRIMARY_STORAGE fill:#f99,stroke:#333
    style DR_STORAGE fill:#99f,stroke:#333

Implementation Steps

Step 1: Plan and Prepare

Define Disaster Recovery Objectives

  • Identify RTO (Recovery Time Objective) and RPO (Recovery Point Objective)

Inventory Assessment

  • Document existing resources and dependencies

Step 2: Configure Data Replication

Persistent Storage Replication

  • Configure synchronous or asynchronous replication between primary and DR sites.
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: dr-replication-demo
  namespace: storage-replication
spec:
  selector:
    matchLabels:
      app: replication
  serviceName: "replication"
  replicas: 2
  template:
    metadata:
      labels:
        app: replication
    spec:
      containers:
      - name: replication-agent
        image: replication-agent:latest
        args:
        - --source-pvc
        - source-storage-pvc
        - --target-pvc
        - target-storage-pvc

Step 3: Implement Cross-Cluster Networking

VPN Configuration for Cluster Connectivity

  • Set up VPN tunnels or configure direct connectivity between cluster sites.

Step 4: Deploy DR Orchestration Tools

RHACM Configuration

  • Deploy Red Hat Advanced Cluster Management for cluster failover management.
apiVersion: cluster.open-cluster-management.io/v1
kind: ManagedCluster
metadata:
  name: disaster-recovery-cluster
spec:
  hubAcceptsClient: true
  managedClusterClientConfigs:
  - url: https://api.dr-cluster.example.com:6443

Step 5: Automate Failover and Recovery

Failover Scripts and Automation

  • Develop scripts to automate the failover process based on RHACM policies.
#!/bin/bash
# Failover script for disaster recovery activation

# Scale down primary workloads
kubectl scale deployment --all --replicas=0 -n primary-workloads

# Scale up DR workloads
kubectl scale deployment --all --replicas=1 -n disaster-recovery-workloads

# Update DNS settings
update-dns --zone=example.com --record=*.example.com --new-ip=dr-cluster-ip

Step 6: Testing and Validation

Disaster Recovery Drills

  • Conduct regular DR drills to test and validate recovery procedures.
# Trigger disaster recovery drill
run-drill --cluster=disaster-recovery-cluster --scenario=full-cluster-failure

Troubleshooting Guide

Common Issues and Solutions

Replication Lag

  • Issue: Data replication falls behind
  • Solution:
  • Increase network bandwidth
  • Optimize replication frequencies
  • Monitor replication service for bottlenecks

Failover Errors

  • Issue: Failover task errors or delays
  • Solution:
  • Verify failover scripts and automation procedures
  • Test DNS updates and propagation
  • Check cluster configuration consistency

Network Connectivity Issues

  • Issue: VPN or network interruptions
  • Solution:
  • Test alternate routes and consider multi-path routing
  • Verify firewall and security group configurations
  • Implement continuous network monitoring

Best Practices

Strategy and Planning

  • Comprehensive Planning: Develop detailed DR plans aligned with business priorities
  • Periodic Reviews: Regularly review DR strategies and update based on changes in infrastructure
  • Stakeholder Engagement: Involve all relevant stakeholders in DR planning and testing

Technology and Tools

  • Automation: Leverage automation for failover processes to minimize human error
  • Monitoring and Alerts: Implement monitoring and alerting for quick detection of failures
  • Compliance and Auditing: Ensure DR plans meet compliance and regulatory requirements

Integration with RH OVE Ecosystem

Multi-Cluster Management

  • Use RHACM for managing multiple clusters, facilitating disaster recovery coordination

Environmental Parity

  • Ensure consistency in configurations between primary and secondary environments

This guide provides the steps and best practices necessary to establish robust disaster recovery systems within the RH OVE ecosystem, ensuring business continuity and data availability even in the event of a major failure or disaster.