We had a node go down in our cluster and its disk had to be wiped. During that time, all nodes in the cluster have restarted at least once. We want to add the bad node back to the ring. It has the same IP/hostname. I follow the steps here for "Adding nodes to an existing cluster." When the process is started up, it reports A node with address <hostname>/<address> already exists, cancelling join. Use cassandra.replace_address if you want to replace this node.
I found this error message in the StorageService using the Gossiper instance to look up the node's state. Apparently, the node knows about it. So I followed the instructions and added the cassandra.replace_address system property and restarted the process. But it reports Cannot replace_address /<address> because it doesn't exist in gossip So which one is it? Does the ring know about it or not? Running "nodetool ring" does show it on all other nodes. I've seen CASSANDRA-8138 andthe conditions are the same, but I can't understand why it thinks it's not part of gossip. What's the difference between the gossip check used to make this determination and the gossip check used for the first error message? Can someone explain? I've since retrieved the node's id and used it to "nodetool removenode". After rebalancing, I added the node back and "nodetool cleaned" up. Everything's up and running, but I'd like to understand what Cassandra was doing.