Minor Description
Simple Repro of this issue: which now I thought was related to the decision made in: https://issues.apache.org/jira/browse/SOLR-3080 but Mark tells me might have been a problem during the zk layout refactoring right before 4.0.
1. Download SOLR 4 production and extract.
2. Replace solr.xml in apache-solr-4.0.0/example/solr/solr.xml with:
<?xml version="1.0" encoding="UTF-8" ?>
<solr persistent="true">
<cores adminPath="/admin/cores" defaultCoreName="collection1" host="${host:}" hostPort="${jetty.port:}" hostContext="${hostContext:}" zkClientTimeout="${zkClientTimeout:15000}">
<core shard="shard1" instanceDir="collection1/" name="collection1" collection="polecat"/>
<core shard="shard1" instanceDir="collection2/" name="collection2" collection="polecat"/>
<core schema="schema.xml" shard="core3" instanceDir="core3/" name="core3" config="solrconfig.xml" collection="polecat" dataDir="data"/>
</cores>
</solr>
3. Start solr with: java -Dbootstrap_confdir=./solr/collection1/conf -Dcollection.configName=myconf -DzkRun -Dsolrcloud.skip.autorecovery=true -jar start.jar
(skip.autorecovery is used because the shards don't exist previously)
Then run this:
Sanity query: http://localhost:8983/solr/polecat/select?q=*%3A*&wt=xml&distrib=true
Remove the core: http://localhost:8983/solr/admin/cores?action=UNLOAD&core=core3&deleteIndex=true
Error query: http://localhost:8983/solr/polecat/select?q=*%3A*&wt=xml&distrib=true
And the sanity query, we will receive 0 records, the error query "no servers hosting shard:". And in the clusterstate.json: "core3":{"replicas":{}}}}