This curriculum spans the equivalent of a multi-workshop technical engagement, covering the design, validation, and operationalization of disaster recovery systems in ELK Stack comparable to internal capability programs at organisations with mature data resilience practices.
Module 1: Architecting High-Availability ELK Clusters
- Designing multi-node Elasticsearch clusters with dedicated master, data, and ingest roles to isolate failure domains.
- Selecting appropriate shard allocation settings to balance data distribution and recovery speed during node outages.
- Configuring minimum master nodes quorum to prevent split-brain scenarios in network partition events.
- Implementing cluster routing allocation awareness across availability zones to ensure replica placement in separate failure zones.
- Choosing between hot-warm-cold architectures versus flat clusters based on data access patterns and recovery time objectives.
- Validating cluster state consistency using Elasticsearch’s _cluster/health and _cluster/state APIs during simulated node failures.
Module 2: Data Replication and Synchronization Strategies
- Configuring cross-cluster replication (CCR) for critical indices with defined follower indices in a secondary cluster.
- Managing replication lag by tuning follower read and write intervals based on WAN latency between data centers.
- Handling write conflicts during failover by implementing timestamp-based conflict resolution at the application layer.
- Enabling consistent snapshots on leader and follower clusters to support point-in-time recovery alignment.
- Monitoring replication checkpoints using the _ccr/stats API to detect replication stalls or backpressure.
- Testing automatic promotion of follower indices to leader status during planned and unplanned outages.
Module 3: Snapshot and Restore Lifecycle Management
- Registering shared snapshot repositories using S3, NFS, or Azure Blob with proper IAM and access controls.
- Scheduling incremental snapshots with cron-based policies aligned to RPO requirements for different data tiers.
- Pruning outdated snapshots using ILM (Index Lifecycle Management) to manage storage costs and restore window coverage.
- Validating snapshot integrity by restoring to a staging cluster and comparing document counts and checksums.
- Handling repository corruption by maintaining multiple geographically separated snapshot locations.
- Automating snapshot verification through scripted API calls that test restore feasibility without full data retrieval.
Module 4: Failover and Failback Runbook Development
- Defining clear escalation paths and decision criteria for declaring a disaster and initiating failover.
- Scripting DNS or load balancer reconfiguration to redirect Logstash and Kibana clients to the recovery cluster.
- Updating Kibana index patterns and saved object references to point to restored or replicated indices.
- Managing client retry logic in Beats and Logstash to prevent data loss during endpoint unavailability.
- Coordinating application team notifications to align log source redirection with cluster readiness.
- Documenting rollback procedures for failback, including data divergence resolution and traffic cutover timing.
Module 5: Log Pipeline Resilience and Buffering
- Configuring persistent queues in Logstash to survive process restarts and network outages.
- Deploying Redis or Kafka as intermediate buffers between Beats and Logstash to absorb ingestion spikes.
- Setting appropriate TTL and retention policies in message brokers based on maximum expected downtime.
- Monitoring broker lag and consumer group offsets to detect ingestion pipeline bottlenecks.
- Implementing dead-letter queues in Logstash to isolate and analyze malformed events during recovery.
- Validating end-to-end delivery by embedding traceable heartbeat events into the log pipeline.
Module 6: Security and Access Continuity
- Replicating role-based access control (RBAC) configurations and API keys to the recovery cluster.
- Synchronizing TLS certificates and keystores across clusters to maintain encrypted communications.
- Ensuring audit logging continues during failover by forwarding security events to an isolated index or external SIEM.
- Managing service account credentials in a secure vault accessible from both primary and DR environments.
- Testing authentication failover for LDAP/Active Directory-integrated setups during network isolation.
- Enforcing consistent index-level security filters in both clusters to prevent privilege escalation post-recovery.
Module 7: Monitoring, Alerting, and DR Validation
- Deploying synthetic transaction monitors to validate end-to-end log ingestion and search functionality.
- Creating dedicated alerting rules for snapshot failures, replication lag, and cluster unavailability.
- Scheduling quarterly DR drills with controlled failover and failback to validate runbook accuracy.
- Measuring RTO and RPO during tests and adjusting configurations to meet SLA targets.
- Using Elasticsearch’s _tasks API to monitor long-running recovery operations like shard relocation.
- Generating post-mortem reports after each test to update configurations and documentation.
Module 8: Capacity Planning and Cost Optimization for DR
- Right-sizing the DR cluster based on reduced ingestion load during outage scenarios.
- Using cold or frozen tiers in the DR environment to minimize costs for long-retention data.
- Calculating network egress costs for cross-region replication and adjusting batch intervals accordingly.
- Implementing autoscaling policies in cloud environments to scale up during recovery and scale down afterward.
- Estimating storage requirements for snapshots based on daily growth and retention period.
- Conducting cost-benefit analysis of active-active versus active-passive architectures for mission-critical indices.