Hi, I'm planning to upgrade to the latest Solr version from our current version of 8.11.1. As per the upgrade notes, looks like I should be able to do a rolling upgrade. The part I'm a bit confused about is the *PKI Authentication* section. It says:
*A rolling upgrade from Solr 8 to Solr 9 requires the following multiple restart sequence:* 1. *Upgrade to Solr 9 and set system properties: solr.pki.sendVersion=v1 and solr.pki.acceptVersions=v1,v2. This will allow Solr 9 nodes to send messages to Solr 8 nodes while the upgrade is in progress.* 2. *Restart with solr.pki.sendVersion=v2 (default, can be unset) and solr.pki.acceptVersions=v1,v2. This will force all nodes to send the new header.* 3. *(Optional) Restart with system property solr.pki.acceptVersions=v2 (default, can be unset) to prevent outdated nodes from connecting to your cluster.* Does this apply to every 8 to 9 upgrade irrespective of the version? Currently, my development environment has 4 nodes (each running on its separate EC2 instance) with 2 shards and 1 replica each. There are three zookeeper instances. I'll have four new EC2 with Solr 9.2 installed and then start them in sequence, each pointing to the existing zookeeper cluster. This should add them as replicas to the existing SolrCloud cloud. What I'm not clear about is 1. Where do I add solr.pki.sendVersion=v1 and solr.pki.acceptVersions=v1,v2 ? Do they have to be in *solr.in.sh <http://solr.in.sh> *for each node? 2. When do I perform step 2 of restarting the new nodes with solr.pki.sendVersion=v2 and solr.pki.acceptVersions=v1,v2 ? Any pointers will be highly appreciated. Thanks, Shamik
