Cross-cluster search (CCS) allows you to configure multiple remote clusters across different locations and to enable federated search queries across all of the configured remote clusters.
Cross-cluster replication (CCR) allows you to replicate indices across multiple remote clusters regardless of where they’re located. This provides tremendous benefit in scenarios of disaster recovery or data locality.
These remote clusters could be:
- Another Elasticsearch cluster of your ECE installation
- An Elasticsearch cluster in a remote ECE installation
- An Elasticsearch cluster hosted on Elastic Cloud
- Any other self-managed Elasticsearch cluster
We’ve deprecated the cross-cluster search template, so you no longer need to use the dedicated cross-cluster search template to search across clusters. You can now use any template to configure remote clusters and search across them when using stack version 6.7 or above. Existing deployments created using this template are not affected by this change, but they need to migrate to another template before upgrading to the next 8.0 major version.
To use CCS or CCR, your environment must meet the following criteria:
- To use CCS, local and remote clusters must be version 6.7.x or higher.
- To use CCR, local and remote clusters must be at version 6.8.9 or higher (in the 6.x branch), or 7.7.1 or higher (in the 7.x branch).
Local and remote clusters must be in compatible versions. Review the Elasticsearch version compatibility table.
- System deployments cannot be used as remote clusters or have remote clusters.
- The local and remote cluster must trust each other.
- Proxies must answer TCP requests on the port 9400. Check the prerequisites for the ports that must permit outbound or inbound traffic.
- Load balancers must pass-through TCP requests on port 9400. Check the configuration details.
The deprecated CCS Deployment Template supports CCS for deployments in version 6.1.x and above without the need to have proxies and load balancers answer on port 9400. However, these remote clusters must be in the same ECE environment and they do not support Cross-cluster Replication. Read more about migrating your deployments using the CCS Deployment Template.