Hi, Since 9.0 Solr can start with an empty SOLR_HOME as it will use defaults in their place <https://solr.apache.org/guide/solr/9_0/upgrade-notes/major-changes-in-solr-9.html>: "Solr no longer requires a solr.xml in $SOLR_HOME. If one is not found, Solr will instead use the default one from $SOLR_TIP/server/solr/solr.xml."
So this motivation for storing solr.xml centrally is no longer valid. I agree with David's comment on the JIRA that this is also a question about what we want solr.xml to be conceptually - a node-config file, or a cluster-config file. We have other locations for cluster-wide configuration. Today I think solr.xml is a mix of the two. A value like "zkClientTimeout" could be cluster-wide while "host" and "hostPort" are of course node-local. I'm also thinking about rolling upgrade scenario. So you do a rolling upgrade from solr 8.11 to 9.0. For the 9.0 nodes you need different configuration, maybe even radically different XML. Today most values in solr.xml is sourced from Java System Properties, which is also a strong hint that this is per-node. Jan > 20. sep. 2022 kl. 22:50 skrev Shawn Heisey <elyog...@elyograg.org.INVALID>: > > On 9/20/22 14:18, Jan Høydahl wrote: >> It has been possible to load solr.xml centrally from zookeeper for a long >> time. >> However, I'm considering deprecating and removing this feature. >> Please see https://issues.apache.org/jira/browse/SOLR-15959 for motivation. >> >> My question to the users list is thus - are you loading solr.xml from >> zookeeper? >> And if yes, why is that capability important for you - i.e. could you not >> configure it per node? > > I have done very little with SolrCloud myself. I converted my tiny little > install to cloud with embedded zk, just the one server, one collection and > one core. I do not have solr.xml in ZK. I did this so I have access to > whatever functionality is cloud-only, should a need ever arise. I fiddle > with that install sometimes to try and answer support questions. Rebuilding > the index only takes about ten minutes, so if I screw something up I just > restore the working config, delete the data directory, restart, and reindex. > > I can see a lot of value in being able to fire up a Solr node with only > /etc/default/solr.in.sh being provided. The solr home can then be provided > completely empty and the node will start, as long as solr.xml is in ZK. > > One thing I think we should do is make it so that Solr starts with some > defaults, if solr.xml is not found at all. We can then bikeshed about what > the defaults should be. > > Making it possible for cloud mode to start without solr.xml might remove most > people's need to have it live in ZK. It would make things easier on docker > users ... they would be able to attach a completely empty volume for the solr > home and Solr would start. They might then go back and add a solr.xml to > provide custom settings. > > Thanks, > Shawn >
