Migrating from Confluence Server to Confluence Data Center: A Comprehensive Step-by-Step Guide

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Pre-Migration Preparation

1. Obtain a Data Center License
   Ensure you have a valid Confluence Data Center license to enable advanced features like clustering and high availability, which are essential for handling larger workloads and ensuring uninterrupted access.

2. Check Compatibility
   Verify that your external database, operating system, and Java version are supported for Confluence Data Center. This step prevents issues during migration and ensures your infrastructure is fully capable of supporting the requirements of the new environment. For details, refer to the supported platforms.

3. Set Up Infrastructure

   • Use a load balancer with session affinity ("sticky sessions") and WebSocket support in front of the Confluence cluster. This configuration ensures traffic is evenly distributed across nodes and maintains user sessions reliably.
   • Prepare a shared home directory accessible to all cluster nodes using the same file path. This directory will store consistent data such as attachments and plugins, which must be shared across all nodes in the cluster.

4. Evaluate App Compatibility
   Check whether your existing apps are compatible with Confluence Data Center. Some apps may require upgrading to Data Center-compatible versions to maintain functionality after migration.

5. Upgrade Confluence
   Upgrade your existing Confluence Server site to the latest version if necessary. This ensures you have access to the newest features, performance improvements, and security patches, reducing the risk of complications during the migration.

Migration Process

1. Apply the Data Center License
   Input your Confluence Data Center license key on the License Details page. Confluence will prompt you to stop the instance before proceeding with the migration. Activating the license enables the clustering and high-availability features needed for a multi-node setup.

2. Enable Cluster Mode
   Stop the current Confluence instance to prevent any changes to the home directory. After restarting, configure cluster settings such as the cluster name, shared home directory (e.g., /var/atlassian/application-data/confluence/shared-home), and join configuration (e.g., multicast). This step enables multiple nodes to work together seamlessly, providing the redundancy and load balancing critical for high performance.

3. Configure Nodes
   Stop the first node and copy the $CONFLUENCE_HOME directory or confluence.cfg.xml file to ensure that all nodes share the same configuration. Start additional nodes using this shared configuration, creating a unified and consistent cluster setup.

4. Test the Setup
   Confirm that all nodes are correctly configured and communicating with each other. Testing ensures the migration is successful and the system is functioning correctly before it goes live.

Post-Migration Steps

1. Validate the Migration
   Review the migrated system to ensure all data and configurations have been transferred accurately. This step confirms that everything is working as expected and no critical components are missing or misconfigured.

2. Reinstall Compatible Apps
   Reinstall any compatible apps, such as Questions for Confluence or Team Calendars, to restore their functionality in the Data Center environment.

3. Monitor Performance
   Use performance monitoring tools to track the cluster's behaviour and make necessary adjustments. This ensures the system operates optimally and any bottlenecks or issues are promptly addressed.

4. Backup Regularly
   Establish a routine backup process to protect your data and provide a reliable recovery option in case of unexpected issues, ensuring long-term stability and security.

By following this guide, you can successfully migrate from Confluence Server to Confluence Data Center, ensuring a reliable, high-performing system with improved scalability and availability.

[Andy Gladstone]

Thanks for taking the time to commit this article to the community @Muhammed Al Hashedi. I believe it will be a great resource as more customers finally spin down their server instances (albeit a year late).

[Ravina]

Thanks for sharing @Muhammed Al Hashedi