Recently, in one of our in-house app, we faced issues with RSolr that failed all our builds in CircleCI.

We faced following RSolr specific errors in our CircleCI builds for the repo.

RSolr::Error::Http:
RSolr::Error::Http - 500 Internal Server Error
Error: Severe errors in solr configuration.

Check your solr log files for more detailed information on what may be wrong.

If you want solr to continue after configuration errors, change it to following configuration instead of null

<abortOnConfigurationError>false</abortOnConfigurationError>

After troubleshooting and debugging, we noticed that our repo in git just had one solr specific file i.e. solr/conf/schema.xml and other Solr specific files were missing or were not generated on CI server.

So we uploaded missing Solr configuration specific files which fixed the issue in our CircleCI build

solr/conf/elevate.xml<br />
solr/conf/solrconfig.xml<br />
solr/conf/spellings.txt<br />
solr/conf/stopwords.txt<br />
solr/conf/synonyms.txt