I'm currently upgrading from HDP 2.6.3 to HDP 3.1.0, following the docs.
On my test cluster, upgrading ambari-infra-solr went fine, but on our main cluster running the backup stage failed. I restarted the ambari-infra-solr server, but it doesn't seem to have come back properly - loading the web UI shows a few GUI elements and a big "loading" spinning. Logging seems broken too - while the server is running, nothing appears in solr.log and there are log4j configuration warnings in stdout.
I added a second ambari-infra-solr server, and it sees the collections but can't access the shards.
Long story short, I don't particularly mind losing the content of the collections - is there an easy way to drop them and start from scratch?