I am planning to upgrade my ES from 1.5.2 to 2.3.1 and I am going through regular upgrade process. I disabled the Shard allocation and I am getting an issue when I am trying to perform the Synced Flush (POST /_flush/synced). I am getting the below error:
"error": "InvalidIndexNameException[[_flush] Invalid index name [flush], must not start with '']",
So, I did some research and found a work around (sort of) for this issue (from Synced Flush Causes Node to Restart) and tried to target an individual index (index name: test01) rather than all indexes and I got this error:
"error": "RemoteTransportException[[test001][inet[/100.82.21.7:9303]][indices:data/write/index]]; nested: InvalidTypeNameException[mapping type name [flush] can't start with '']; ",
Not sure if the ES 1.5.2 has any issues with the Synced Flush API call or if I need additional plugins involved in my current ES 1.5.2 setup!!
Any inputs will be appreciated..