| .. _cassandra-rackdc: |
| |
| cassandra-rackdc.properties file |
| ================================ |
| |
| Several :term:`snitch` options use the ``cassandra-rackdc.properties`` configuration file to determine which :term:`datacenters` and racks cluster nodes belong to. Information about the |
| network topology allows requests to be routed efficiently and to distribute replicas evenly. The following snitches can be configured here: |
| |
| - GossipingPropertyFileSnitch |
| - AWS EC2 single-region snitch |
| - AWS EC2 multi-region snitch |
| |
| The GossipingPropertyFileSnitch is recommended for production. This snitch uses the datacenter and rack information configured in a local node's ``cassandra-rackdc.properties`` |
| file and propagates the information to other nodes using :term:`gossip`. It is the default snitch and the settings in this properties file are enabled. |
| |
| The AWS EC2 snitches are configured for clusters in AWS. This snitch uses the ``cassandra-rackdc.properties`` options to designate one of two AWS EC2 datacenter and rack naming conventions: |
| |
| - legacy: Datacenter name is the part of the availability zone name preceding the last "-" when the zone ends in -1 and includes the number if not -1. Rack name is the portion of the availability zone name following the last "-". |
| |
| Examples: us-west-1a => dc: us-west, rack: 1a; us-west-2b => dc: us-west-2, rack: 2b; |
| |
| - standard: Datacenter name is the standard AWS region name, including the number. Rack name is the region plus the availability zone letter. |
| |
| Examples: us-west-1a => dc: us-west-1, rack: us-west-1a; us-west-2b => dc: us-west-2, rack: us-west-2b; |
| |
| Either snitch can set to use the local or internal IP address when multiple datacenters are not communicating. |
| |
| =========================== |
| GossipingPropertyFileSnitch |
| =========================== |
| |
| ``dc`` |
| ------ |
| Name of the datacenter. The value is case-sensitive. |
| |
| **Default value:** DC1 |
| |
| ``rack`` |
| -------- |
| Rack designation. The value is case-sensitive. |
| |
| **Default value:** RAC1 |
| |
| =========================== |
| AWS EC2 snitch |
| =========================== |
| |
| ``ec2_naming_scheme`` |
| --------------------- |
| Datacenter and rack naming convention. Options are ``legacy`` or ``standard`` (default). **This option is commented out by default.** |
| |
| **Default value:** standard |
| |
| |
| .. NOTE:: |
| YOU MUST USE THE ``legacy`` VALUE IF YOU ARE UPGRADING A PRE-4.0 CLUSTER. |
| |
| =========================== |
| Either snitch |
| =========================== |
| |
| ``prefer_local`` |
| ---------------- |
| Option to use the local or internal IP address when communication is not across different datacenters. **This option is commented out by default.** |
| |
| **Default value:** true |
| |
