Hi all, Following a discussion with our adminsys, I have a very practical question. We use cassandra proxies (-Dcassandra.join_ring=false) as coordinators for PHP clients (a loooooot of PHP clients).
Our problem is that restarting Cassandra on proxies sometimes fails with the following error : ERROR [main] 2021-03-16 14:18:46,236 CassandraDaemon.java:803 - Exception encountered during startup java.lang.RuntimeException: A node with address XXXXXXXXXXXXXXXX/10.120.1.XXX already exists, cancelling join. Use cassandra.replace_address if you want to replace this node. The node mentioned in the ERROR is the one we are restarting... and the start fails. Of course doing a manual start after works fine. This message doesn't make sense... hostId didn't changed for this proxy (I am sure of me : system.local, IP, hostname, ... nothing changed... just the restart). What I suppose (we don't all agree about this) is that, as proxies don't have data, they start very quickly. Too quickly for gossip protocol knows that the node was down. Could this ERROR log be explained if the node is still known as UP by seeds servers if the state of the proxy in gossip protocol is not updated because stop/start is made too quickly ? If this hypothesis seems possible, what reasonable delay (with technical arguments) should be implemented between stop and start ? We have ~ 100 proxies and 12 classical Cassandra (4 of them are seeds)... Thx in advance
