Initializing single-token architecture datacenters

Deploy a single-token datacenter when not using virtual nodes (vnodes).

1. Suppose you install DataStax Enterprise on these nodes:
   • node0 10.168.66.41 (seed1)
   • node1 10.176.43.66
   • node2 10.168.247.41
   • node3 10.176.170.59 (seed2)
   • node4 10.169.61.170
   • node5 10.169.30.138
2. Calculate the token assignments as described in Calculating tokens for single-token architecture nodes.

   The following tables list tokens for a 6 node cluster with a single datacenter or two datacenters.

   Table 1. Single Datacenter

   Node	Token
   node0	0
   node1	21267647932558653966460912964485513216
   node2	42535295865117307932921825928971026432
   node3	63802943797675961899382738893456539648
   node4	85070591730234615865843651857942052864
   node5	106338239662793269832304564822427566080

   Table 2. Multiple Datacenters

   Node	Token	Offset	Datacenter
   node0	0	NA	DC1
   node1	56713727820156410577229101238628035242	NA	DC1
   node2	113427455640312821154458202477256070485	NA	DC1
   node3	100	100	DC2
   node4	56713727820156410577229101238628035342	100	DC2
   node5	113427455640312821154458202477256070585	100	DC2

3. If the nodes are behind a firewall, open the required ports for internal/external communication.
4. If DataStax Enterprise is running, stop the node and clear the data:
   • Package installations: To stop DSE:

     sudo service dse stop

     To remove data from the default directories:

     sudo rm -rf /var/lib/cassandra/*

   • Tarball installations:
     From the installation location, stop the database:

     bin/dse cassandra-stop

     Remove all data:

     cd /var/lib/cassandra/data &&
     sudo rm -rf data/* commitlog/* saved_caches/* hints/* 

5. Configure properties in cassandra.yaml on each new node, following the configuration of the other nodes in the cluster.
   Tip: Use the yaml_diff tool to review and make appropriate changes to the cassandra.yaml and dse.yaml configuration files.
   1. Configure node properties.
      • initial_token: token_value_from_calculation
      • num_tokens: 1
      • -seeds: internal_IP_address of each seed node
        Important: Include at least one seed node from each datacenter. DataStax recommends more than one seed node per datacenter. Do not make all nodes seed nodes.
      • listen_address: empty

        If not set, DSE asks the system for the local address, which is associated with its host name. In some cases, DSE does not produce the correct address, which requires specifying the listen_address.

      • auto_bootstrap: false

        Add the bootstrap setting only when initializing a new cluster with no data.

      • endpoint_snitch: snitch

        See endpoint_snitch and snitches.

        Important: Do not use the DseSimpleSnitch. The DseSimpleSnitch (default) is used only for single-datacenter deployments (or single-zone deployments in public clouds), and does not recognize datacenter or rack information.

        Snitch	Configuration file
        GossipingPropertyFileSnitch	cassandra-rackdc.properties file
        Configuring the Amazon EC2 single-region snitch
        Configuring Amazon EC2 multi-region snitch
        Configuring the Google Cloud Platform snitch
        	cassandra-topology.properties file

      • If using a cassandra.yaml or dse.yaml file from a previous version, check the Upgrade Guide for removed settings.
6. Set the properties in the dse.yaml file as required by your use case.
7. In the cassandra-rackdc.properties (GossipingPropertyFileSnitch) or cassandra-topology.properties (PropertyFileSnitch) file, assign datacenter and rack names to the IP addresses of each node, and assign a default datacenter name and rack name for unknown nodes.
   Note: Migration information: The GossipingPropertyFileSnitch always loads cassandra-topology.properties when the file is present. Remove the file from each node on any new cluster, or any cluster migrated from the PropertyFileSnitch.

   # Transactional Node IP=Datacenter:Rack
   110.82.155.0=DC_Transactional:RAC1
   110.82.155.1=DC_Transactional:RAC1
   110.54.125.1=DC_Transactional:RAC2
   110.54.125.2=DC_Analytics:RAC1
   110.54.155.2=DC_Analytics:RAC2
   110.82.155.3=DC_Analytics:RAC1
   110.54.125.3=DC_Search:RAC1
   110.82.155.4=DC_Search:RAC2
   
   # default for unknown nodes
   default=DC1:RAC1

   Note: After making any changes in the configuration files, you must the restart the node for the changes to take effect.
8. After you have installed and configured DataStax Enterprise on all nodes, start the seed nodes one at a time, and then start the rest of the nodes:
   • Package installations: Starting DataStax Enterprise as a service
   • Tarball installations: Starting DataStax Enterprise as a stand-alone process
9. Check that your cluster is up and running:

   dsetool status

   Note: If DSE has problems starting, look for starting DSE troubleshooting and other articles in the Support Knowledge Center.

Datacenter: Cassandra
=======================
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address         Load        Tokens    Owns    Host ID             Rack
UN 110.82.155.0    21.33 KB    256       33.3%   a9fa31c7-f3c0-...   RAC1
UN 110.82.155.1    21.33 KB    256       33.3%   f5bb416c-db51-...   RAC1
UN 110.82.155.2    21.33 KB    256       16.7%   b836748f-c94f-...   RAC1