AEM Replication & Publishing

Purpose

Configure and manage content replication between AEM instances including publish agents, reverse replication, content distribution, and publish queue management.

When to Use (Triggers)

• User mentions "replication," "publishing," "activation," or "content distribution"
• References to replication agents, publish queues, or tree activation
• Questions about content sync, reverse replication, or distribution packages
• Requests involving publish failures, queue management, or agent configuration
• Discussion of Sling Content Distribution (Cloud Service) or CRX DE replication

Core Capabilities

• Configure forward and reverse replication agents
• Implement Sling Content Distribution for AEM Cloud Service
• Design content distribution topologies (single publish, publish farm)
• Troubleshoot replication queue blockages and serialization errors
• Set up content invalidation and flush agents for dispatcher

Domain Knowledge Required

Technical Foundation

• Replication agent architecture (transport, serialization, triggers)
• Sling Content Distribution (Golden Publish, queue-based distribution)
• HTTP/HTTPS transport layer and authentication for replication
• JCR observation and event-based replication triggers

AEM-Specific Context

• Agent types: default, reverse, static, flush, custom
• Replication queue management (block, retry, force retry, clear)
• Tree activation vs. individual page activation
• On-modification vs. on-receive triggers
• Content distribution in AEM Cloud Service (no traditional replication)

Implementation Approach

Step 1: Topology Design

Plan the replication architecture based on requirements.

• Map author → publish instances and their relationships
• Determine if Sling Content Distribution applies (Cloud Service)
• Plan dispatcher flush agent configuration
• Design reverse replication for UGC or form submissions

Step 2: Agent Configuration

Set up replication agents for each connection.

• Configure transport URI and authentication
• Set serialization type (default, dispatcher flush, static)
• Define trigger settings (on-modification, on-receive, scheduled)
• Configure retry and batch settings for performance

Step 3: Queue Management

Implement monitoring and handling for distribution queues.

• Set up queue monitoring with size and age alerts
• Configure dead-letter queues for persistent failures
• Implement automatic retry with exponential backoff
• Plan manual intervention procedures for blocked queues

Step 4: Content Distribution Patterns

Define how different content types are distributed.

• Configure tree activation for bulk publishing
• Set up scheduled activation for time-sensitive content
• Implement deep vs. shallow activation strategies
• Handle reference resolution for linked assets and pages

Step 5: Validation & Monitoring

Ensure replication reliability and performance.

• Test replication agent connectivity and authentication
• Validate content integrity post-replication
• Monitor replication latency (author-to-publish delay)
• Set up alerting for queue depth and failure rates

Quality Checklist

• [ ] All publish instances receive content within SLA time
• [ ] Replication queues drain under normal load without blocking
• [ ] Failed replication creates actionable alerts
• [ ] Dispatcher flush agents invalidate correct cache paths
• [ ] Reverse replication captures UGC without data loss
• [ ] Bulk activation handles 1000+ pages without timeout
• [ ] Agent credentials stored securely (not in plain text)
• [ ] Content integrity verified between author and publish

Related Skills

• aem-dispatcher-configuration (cache invalidation via flush agents)
• aem-caching-strategy (cache coherency with replication)
• aem-monitoring-alerting (replication queue monitoring)

Example Use Cases

1. Multi-Region Publish Farm: Configure replication to 6 publish instances across 3 geographic regions with dispatcher flush agents ensuring cache consistency and regional failover support.
2. Scheduled Go-Live: Implement timed activation for a product launch requiring 500+ pages and 2000+ assets to go live simultaneously at a specific date/time across all markets.
3. User-Generated Content Pipeline: Set up reverse replication from publish instances to author for comment moderation, form submissions, and user rating aggregation with conflict resolution.

Notes

• AEM Cloud Service uses Sling Content Distribution — traditional replication agents don't apply
• Tree activation is resource-intensive — schedule during low-traffic periods
• Flush agents should target dispatcher, not publish instances directly
• Replication of large binaries (video, PDFs) may require dedicated agents with higher timeouts