YARN Registry DNS instance fails to start
The YARN Registry DNS instance fails to start if another process on the host is bound to port 53. Ensure no other services that are binding to port 53 are on the host where the YARN Registry DNS instance is deployed.
Class Loading Issue When Starting Solr:
If you do not follow sequential steps during the upgrade, the Infra Solr instance might fail to start with the following exception:
null:org.apache.solr.common.SolrException: Error loading class
If you see this exception, follow the steps in this HCC article to work around the issue: