Cassandra collector

Cassandra is an open-source NoSQL database management system.

This module will monitor one or more Cassandra servers, depending on your configuration.

Requirements

• Cassandra with Prometheus JMX Exporter.

To configure Cassandra with the JMX Exporter:

Note: paths can differ depends on your setup.

• Download latest jmx_exporter jar file and install it in a directory where Cassandra can access it.
• Add the jmx_exporter.yaml file to /etc/cassandra.
• Add the following line to /etc/cassandra/cassandra-env.sh

  JVM_OPTS="$JVM_OPTS $JVM_EXTRA_OPTS -javaagent:/opt/jmx_exporter/jmx_exporter.jar=7072:/etc/cassandra/jmx_exporter.yaml
• Restart cassandra service.

Metrics

All metrics have "cassandra." prefix.

Labels per scope:

• global: no labels.
• thread pool: thread_pool.

Metric	Scope	Dimensions	Units
client_requests_rate	global	read, write	requests/s
client_request_read_latency_histogram	global	read, write	seconds
client_request_write_latency_histogram	global	read, write	seconds
client_requests_latency	global	read, write	seconds
row_cache_hit_ratio	global	hit_ratio	percentage
row_cache_hit_rate	global	hits, misses	events/s
row_cache_utilization	global	used	percentage
row_cache_size	global	size	bytes
key_cache_hit_ratio	global	hit_ratio	percentage
key_cache_hit_rate	global	hits, misses	events/s
key_cache_utilization	global	used	percentage
key_cache_size	global	size	bytes
storage_live_disk_space_used	global	used	bytes
compaction_completed_tasks_rate	global	completed	tasks/s
compaction_pending_tasks_count	global	pending	tasks
compaction_compacted_rate	global	compacted	bytes/s
thread_pool_active_tasks_count	thread pool	active	tasks
thread_pool_pending_tasks_count	thread pool	pending	tasks
thread_pool_blocked_tasks_count	thread pool	blocked	tasks
thread_pool_blocked_tasks_rate	thread pool	blocked	tasks/s
jvm_memory_used	global	heap, nonheap	bytes
jvm_gc_rate	global	parnew, cms	gc/s
jvm_gc_time	global	parnew, cms	seconds
dropped_messages_rate	global	dropped	messages/s
client_requests_timeouts_rate	global	read, write	timeout/s
client_requests_unavailables_rate	global	read, write	exceptions/s
client_requests_failures_rate	global	read, write	failures/s
storage_exceptions_rate	global	storage	exceptions/s

Configuration

Edit the go.d/cassandra.conf configuration file using edit-config from the Netdata config directory, which is typically at /etc/netdata.

cd /etc/netdata # Replace this path with your Netdata config directory
sudo ./edit-config go.d/cassandra.conf

Here is an example for 2 servers:

jobs:
  - name: local
    url: http://127.0.0.1:7072/metrics

  - name: remote
    url: http://203.0.113.10:7072/metrics

For all available options please see module configuration file.

Troubleshooting

To troubleshoot issues with the cassandra collector, run the go.d.plugin with the debug option enabled. The output should give you clues as to why the collector isn't working.

• Navigate to the plugins.d directory, usually at /usr/libexec/netdata/plugins.d/. If that's not the case on your system, open netdata.conf and look for the plugins setting under [directories].

  cd /usr/libexec/netdata/plugins.d/

• Switch to the netdata user.

  sudo -u netdata -s

• Run the go.d.plugin to debug the collector:

  ./go.d.plugin -d -m cassandra

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