I upgraded my cluster based on the instructions from the link
After upgrading none of the non-data nodes started.
All of them had the below error
[2019-02-20T22:57:35,922][WARN ][o.e.b.ElasticsearchUncaughtExceptionHandler] [node1] uncaught exception in thread [main]
org.elasticsearch.bootstrap.StartupException: java.lang.IllegalStateException: failed to obtain node locks, tried [[/etc/elasticsearch/data]] with lock id ; maybe these locations are not writable or multiple nodes were started without increasing [node.max_local_storage_nodes] (was )?
I even tried setting node.max_local_storage_nodes the value to 5 and started and still the error persisted.