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Cassandra Snitch Configuration

The snitch determines how Cassandra maps nodes to datacenters and racks.

Available Snitches

Snitch Use Case
SimpleSnitch Single DC, no rack awareness
GossipingPropertyFileSnitch Production (recommended)
PropertyFileSnitch Legacy
Ec2Snitch AWS single region
Ec2MultiRegionSnitch AWS multi-region
GoogleCloudSnitch GCP
RackInferringSnitch IP-based inference

Configuration

# cassandra.yaml
endpoint_snitch: GossipingPropertyFileSnitch

# cassandra-rackdc.properties
dc=datacenter1
rack=rack1

# Optional
prefer_local=true
dc_suffix=_analytics

Multi-DC Setup

# Node in DC1
dc=us-east
rack=rack1

# Node in DC2
dc=eu-west
rack=rack1

Cloud Snitches

AWS (Ec2Snitch)

# cassandra.yaml
endpoint_snitch: Ec2Snitch

# Automatic:
# DC = region (us-east-1)
# Rack = availability zone (us-east-1a)

AWS Multi-Region

# cassandra.yaml
endpoint_snitch: Ec2MultiRegionSnitch
listen_address: <private_ip>
broadcast_address: <public_ip>

GCP

# cassandra.yaml
endpoint_snitch: GoogleCloudSnitch

# Automatic:
# DC = project:region
# Rack = zone

Changing Snitch

# 1. Update cassandra.yaml on all nodes
# 2. Update cassandra-rackdc.properties
# 3. Rolling restart cluster
# 4. Run repair

nodetool repair -full

Verifying Topology

# Check datacenter/rack assignment
nodetool status

# Detailed gossip info
nodetool gossipinfo | grep -E "DC|RACK"

Next Steps