solr: Add note about SolrCloud mode
@@ -12,6 +12,8 @@ Metadata associated with the solr plugin for collectd can be found <a target="_b
### DESCRIPTION
+*NOTE: This plugin can collect metrics from Solr only when a Solr instance is running in SolrCloud mode*
+
This is the SignalFx solr plugin. Follow these instructions to install the solr plugin for collectd.
The <a target="_blank" href="https://github.com/signalfx/collectd-solr">solr-collectd</a> plugin collects metrics from solr instances hitting these endpoints: <a target="_blank" href="https://lucene.apache.org/solr/guide/6_6/performance-statistics-reference.html">statistics</a> (default metrics) and <a target="_blank" href="https://lucene.apache.org/solr/guide/6_6/metrics-reporting.html">metrics</a> (optional metrics).
