/etc/cassandra/cassandra.yaml
- cluster_name can be anything chosen by you to describe the name of the cluster. Space is allowed but make sure you wrap everything in quotes. All members of this cluster must have the same name.
- num_tokens is the number of virtual nodes within a Cassandra instance. This is used to partition the data and spread the data throughout the cluster. A good starting point is 256.
- seeds are the IP addresses of the clusters seed servers. Seed nodes are used as known places where cluster information (such as a list of nodes in the cluster) can be obtained. They are not a single point of failure as all active nodes have this information, they are just known locations that can be relied on to have the information when other machines can come and go. It’s recommended that there are 3 seed nodes per data centre.
- listen_address is the IP address that Cassandra will listen on for internal (Cassandra to Cassandra) communication will occur. Cassandra will try to guess your machines IP address if you leave it blank, but it’s best to specify it yourself. This will change on each node.
- rpc_address is the IP address that Cassandra will listen on for client based communication, such as through the CQL protocol. This will change on each node.
- endpoint_snitch is the ‘snitch’ used by Cassandra. A snitch is what tells Cassandra which data center and rack a node belongs to within a cluster. There are various types that could be used here, however describing them is outside the scope of this guide.
Example for node 1:
Example for node 2:
Example for node 3:
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cluster_name: 'JC Cluster'
num_tokens: 256
seed_provider:
- class_name: org.apache.cassandra.locator.SimpleSeedProvider
- seeds: 10.0.0.1, 10.0.0.2
listen_address: 10.0.0.3
rpc_address: 10.0.0.3
endpoint_snitch: GossipingPropertyFileSnitch
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vi /etc/cassandra/cassandra-rackdc.properties
Example for node 1:
Example for node 2:
Example for node 3:
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dc=uk_dc
rack=rack2
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Finally, remove the config file cassandra-topology.properties from the etc dir as that’s not used with our configuration.
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rm /etc/cassandra/cassandra-topology.properties
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service cassandra start
Once all of your services are started you can use the nodetool status command to check the status of your nodes. Run this from any Cassandra server. As you can see with the below output, all three servers are available in the uk_dc data centre on rack1 and rack2.
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nodetool status
Datacenter: uk_dc
===============
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address Load Tokens Owns Host ID Rack
UN 10.0.0.3 124.64 KB 256 ? bb57bbee-3fe4-47b1-9249-cd3f90cd9718 rack2
UN 10.0.0.2 124.7 KB 256 ? 6669bac4-52c5-49fb-a68a-da065f20ae2c rack1
UN 10.0.0.1 106.45 KB 256 ? ddee28dd-7909-4428-bebd-023e4e560db5 rack1
Note: Non-system keyspaces don't have the same replication settings, effective ownership information is meaningless
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