Hi all, Our team use Solrcloud for Solr 5.1 and are investigating an upgrade to 7.3 Currently we have a working scale-up approach for adding a new server to the cluster beyond the initial collection creation. We’ve automated the install of Solr on new servers and, following that, we register the new instance with zookeeper so that the server will be included in the list of live nodes. Finally we use the CoreAdmin API ‘Create’ command to associate the new node with our collection. Solr 5.1's CoreAdmin Create command would conveniently auto-assign the new node to the shard with the least nodes.
In Solr 7.3, the CoreAdmin API documentation warns us not to use the Create command with SolrCloud. We tried 7.3’s CoreAdmin API Create command regardless and, unsurprisingly, it did not work. The 7.3 documentation suggests we use the Collections API AddReplica command.The problem with AddReplica is that it expects us to specify the shard name. This is unfortunate as it makes it hard for us to keep shards balanced. It puts the onus on us to work out the least populated shard via a call to the cluster status endpoint. With that we now face the problem managing this correctly when scaling up multiple servers at once. Are we missing something here? Is there really no way for a node to be auto-assigned to a shard in 7.3? And if so, are there any recommendations for an approach to reliably doing this ourselves? Thanks! Adam
