Cassandra sometimes throws unauthorized error

Question

We have a multi-node Cassandra cluster and we use Cassandra python driver for our insert queries. Everything was fine till we removed one of our nodes from the cluster using following command:

nodetool removenode force

Now our driver meets following error not always but once in a while:

(<class 'cassandra.Unauthorized'>, Unauthorized(u'code=2100 [Unauthorized] message="User username has no MODIFY permission on <table keyspace.tablename> or any of its parents"',), <traceback object at 0x7fe2447910e0>)

We use same user for all our insert queries and it has all required permissions.

What is our cluster's problem?

More info: Cassandra version 3.0.0 Python driver version 3.0.0

Answer 1

Since you forced a remove node data may now be inconsistent you should start with a repair on the system_auth keyspace.

I would then follow up with a full repair of all the other keyspaces.