Cassandra nodes appearing in different datacenters - cassandra

Question

I am having trouble with three nodes in Cassandra, each of them in an individual computer, as I am trying to set up my first Cassandra structure. I have set up everything as in the Datastax documentation, and I have the same configuration in the different cassandra.yaml of each machine (changing the relative ips). The thing is that after configuring everything, each computer sees each other as DN, and each machine (localhost) appears as UN, with the difference that in the .101 computer I can see two different datacenters, while in the other computers only one datacenter appears.
So in my 192.168.1.101 machine when I type
sudo nodetool status
I get this output:
Datacenter: DC1
===============
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address Load Tokens Owns Host ID Rack
DN 192.168.1.200 ? 256 ? 968d5d1e-a113-40ce-9521-e392a927ea5e r1
DN 192.168.1.102 ? 256 ? fc5c2dbe-8834-4040-9e77-c3d8199b6767 r1
Datacenter: dc1
===============
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address Load Tokens Owns Host ID Rack
UN 127.0.0.1 446.13 KB 256 ? 6d28d540-2b44-4522-8612-b5f70a3d7d52 rack1
While when I type "nodetool status" in one of the other two machines, I get this output:
Datacenter: datacenter1
=======================
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address Load Tokens Owns Host ID Rack
DN 192.168.1.200 ? 256 ? 968d5d1e-a113-40ce-9521-e392a927ea5e rack1
UN 127.0.0.1 506,04 KB 256 ? fc5c2dbe-8834-4040-9e77-c3d8199b6767 rack1
DN 192.168.1.101 ? 256 ? 6d28d540-2b44-4522-8612-b5f70a3d7d52 rack1
In OpsCenter I can only see my 192.168.1.101 machine:
... Which makes me think that something's odd in the yaml file of this machine and the others, but I have checked several times and it seems that the configuration is the same in the other computers. Enpoint_snitch is set to "GossipingPropertyFileSnitch".
Any tips on how to solve the reason why all the other nodes appear as Down Normal and why I am getting two datacenters would be highly appreaciated. It's driving me crazy!
Thanks for reading.

Answer 1

Any tips on how to solve the reason why all the other nodes appear as Down Normal and why I am getting two datacenters would be highly appreaciated. It's driving me crazy!
On each machine, edit the $CASSANDRA_HOME/conf/cassandra-rackdc.properties file to set:
dc=dc1
rack=rack1
nodetool status shows that you set the wrong DC name for 2 nodes (DC1 instead of dc1). It's case sensitive

Answer 2

It looks like some of the installed nodes were dead, so I deleted the nodes that were not the local machine in each of the nodes, ie:
nodetool removenode 968d5d1e-a113-40ce-9521-e392a927ea5e
nodetool removenode fc5c2dbe-8834-4040-9e77-c3d8199b6767
and after that I got the right output when I executed nodetools status
[machine1]~$ sudo nodetool status
Datacenter: dc1
===============
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address Load Tokens Owns Host ID Rack
UN 127.0.0.1 286.93 KB 256 ? 6d28d540-2b44-4522-8612-b5f70a3d7d52 rack1
[machine2]~$ sudo nodetool status
Datacenter: dc1
===============
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address Load Tokens Owns Host ID Rack
UN 127.0.0.1 268.45 KB 256 ? fc5c2dbe-8834-4040-9e77-c3d8199b6767 rack1
And made sure that the parameters cluster_name, seeds, listen_address and rpc_address were right.
cluster_name: 'Test Cluster'
seeds: "192.168.1.101, 192.168.1.102"
listen_address: 192.168.1.101
rpc_address: 192.168.1.101
Changing listen_address and rpc_address to the corresponding ip of each machine in their corresponding cassandra.yaml file.
After that I got the right output (I am using only 2 machines for the nodes now):
Datacenter: dc1
===============
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address Load Tokens Owns (effective) Host ID Rack
UN 192.168.1.101 309.13 KB 256 51.6% 6d28d540-2b44-4522-8612-b5f70a3d7d52 rack1
UN 192.168.1.102 257.15 KB 256 48.4% fc5c2dbe-8834-4040-9e77-c3d8199b6767 rack1