Are you running chef/puppet or similar?
Recently I'm facing a problem with cassandra nodes. Nodes go down very frequently.
I went through system.log and found the reason that somehow c* triggers draining process.
I know the purpose of nodetool drain but it should not trigger automatically, right ?
or is there any specific settings for the same ?
we are using C*-2.1.13.
please let me know if you need more info.