Sometimes, despite our best efforts, even nodetool removenode fails to completely take a node out of the cluster. This can happen if the remove process hangs, or if another node crashes during this time. Whatever the cause, sometimes a node may appear to be removed to some nodes, but not to others. For edge cases like these, the nodetool assassinate command exists, and is used as follows:
nodetool assassinate 192.168.0.102
This command completely removes the node from the cluster, without streaming any data. It should only be used as a last resort, and only if either decommission or removenode fail to work.
If a node is particularly stubborn about leaving gossip, you may need to run assassinate ...
