Single data center deployment per workload type

Steps for configuring nodes in a deployment scenario in a mixed workload cluster that has only one data center for each type of workload.

This configuration example describes installing an 8 node cluster spanning 2 racks in a single data center. The default consistency level is QUORUM.

1. Suppose the nodes have the following IPs and one node per rack will serve as a seed:
   • node0 110.82.155.0 (Cassandra seed)
   • node1 110.82.155.1 (Cassandra)
   • node2 110.82.155.2 (Cassandra)
   • node3 110.82.155.3 (Analytics seed)
   • node4 110.82.155.4 (Analytics)
   • node5 110.82.155.5 (Analytics)
   • node6 110.82.155.6 (Search)
   • node7 110.82.155.7 (Search)
2. If the nodes are behind a firewall, open the required ports for internal/external communication. See Configuring firewall port access.
3. If DataStax Enterprise is running, stop the nodes and clear the data:
   • Installer-Services and Package installations:

     $ sudo service dse stop
     $ sudo rm -rf /var/lib/cassandra/* ## Clears the data from the  default directories

   • Installer-No Services and Tarball installations:

     From the install directory:

     $ sudo bin/dse cassandra-stop
     $ sudo rm -rf /var/lib/cassandra/* ## Clears the data from the default directories

   • Installer-No Services and Tarball installations:

     From the install directory:

     $ sudo bin/dse cassandra-stop
     $ sudo rm -rf /var/lib/cassandra/*  # Clears the data from the  default directories 

     Note: If you are clearing data from an AMI installation for restart, you need to preserve the log files.
4. Set the properties in the cassandra.yaml file for each node, located in:
   Important: After making any changes in the cassandra.yaml file, you must restart the node for the changes to take effect.

   Properties to set:

   Note: If the nodes in the cluster are identical in terms of disk layout, shared libraries, and so on, you can use the same copy of the cassandra.yaml file on all of them.
   • num_tokens: 256 for Cassandra nodes
   • num_tokens: 1 for Hadoop and Solr nodes
   • num_tokens: 32 to 64 for Solr nodes when using vnodes; otherwise num_tokens: 1
   • -seeds: internal_IP_address of each seed node
   • listen_address: empty

     If not set, Cassandra asks the system for the local address, the one associated with its host name. In some cases Cassandra doesn't produce the correct address and you must specify the listen_address.

   • endpoint_snitch: snitch See endpoint_snitch. If you are changing snitches, see Switching snitches.
   • auto_bootstrap: false

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

   • endpoint_snitch: snitch

     For more information, see endpoint_snitch and About Snitches.

   • If you are using a cassandra.yaml from a previous version, remove the following options, as they are no longer supported by DataStax Enterprise:

     ## Replication strategy to use for the auth keyspace.
     auth_replication_strategy: org.apache.cassandra.locator.SimpleStrategy
     
     auth_replication_options:
         replication_factor: 1

   Example:

   cluster_name: 'MyDemoCluster'
   num_tokens: 256
   seed_provider:
     - class_name: org.apache.cassandra.locator.SimpleSeedProvider
       parameters:
            - seeds: "110.82.155.0,110.82.155.3"
   listen_address:
   endpoint_snitch: GossipingPropertyFileSnitch

5. In the cassandra-rackdc.properties (GossipingPropertyFileSnitch) or cassandra-topology.properties (PropertyFileSnitch) file, use your naming convention to assign data center and rack names to the IP addresses of each node, and assign a default data center name and rack name for unknown nodes.
   The location of these property files depends on the type of install:

   • Installer-Services and Package installations: /etc/dse/cassandra
   • Installer-No Services and Tarball installations: install_location/resources/cassandra/conf

   Example:

   # Cassandra Node IP=Data Center:Rack
   110.82.155.0=DC_Cassandra:RAC1
   110.82.155.1=DC_Cassandra:RAC1
   110.82.155.2=DC_Cassandra:RAC1
   110.82.155.3=DC_Analytics:RAC1
   110.82.155.4=DC_Analytics:RAC1
   110.82.155.5=DC_Analytics:RAC1
   110.82.155.6=DC_Solr:RAC1
   110.82.155.7=DC_Solr:RAC1
   
   # default for unknown nodes
   default=DC1:RAC1

6. 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:
   • Packages/Services: See Starting DataStax Enterprise as a service.
   • Tarball/No Services: See Starting DataStax Enterprise as a stand-alone process.
   Note: If the node has restarted because of automatic restart, you must stop the node and clear the data directories, as described above.
7. Check that your cluster is up and running:
   • Installer-Services and Package installations: $ nodetool status
   • Installer-No Services and Tarball installations: $ install_location/bin/nodetool status

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
Datacenter: Analytics
=======================
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address         Load        Owns      Host ID               Tokens         Rack
UN 110.82.155.3    28.44 KB    13.0.%    e2451cdf-f070- ...    -922337....    RAC1
UN 110.82.155.4    44.47 KB    16.7%     f9fa427c-a2c5- ...    30745512...    RAC1 
UN 110.82.155.5    54.33 KB    23.6%     b9fc31c7-3bc0- ..-    45674488...    RAC1
Datacenter: Solr
=======================
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address         Load        Owns      Host ID               Tokens         Rack
UN 110.82.155.6    15.44 KB    50.2.%    e2451cdf-f070- ...    9243578....    RAC1
UN 110.82.155.7    18.78 KB    49.8.%    e2451cdf-f070- ...    10000          RAC1