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Cassandra

Plugin: go.d.plugin Module: cassandra

Overview

This collector gathers metrics about client requests, cache hits, and many more, while also providing metrics per each thread pool.

The JMX Exporter is used to fetch metrics from a Cassandra instance and make them available at an endpoint like http://127.0.0.1:7072/metrics.

This collector is supported on all platforms.

This collector supports collecting metrics from multiple instances of this integration, including remote instances.

Default Behavior

Auto-Detection

This collector discovers instances running on the local host that provide metrics on port 7072.

On startup, it tries to collect metrics from:

Limits

The default configuration for this integration does not impose any limits on data collection.

Performance Impact

The default configuration for this integration is not expected to impose a significant performance impact on the system.

Metrics

Metrics grouped by scope.

The scope defines the instance that the metric belongs to. An instance is uniquely identified by a set of labels.

Per Cassandra instance

These metrics refer to the entire monitored application.

This scope has no labels.

Metrics:

MetricDimensionsUnit
cassandra.client_requests_rateread, writerequests/s
cassandra.client_request_read_latency_histogramp50, p75, p95, p98, p99, p999seconds
cassandra.client_request_write_latency_histogramp50, p75, p95, p98, p99, p999seconds
cassandra.client_requests_latencyread, writeseconds
cassandra.row_cache_hit_ratiohit_ratiopercentage
cassandra.row_cache_hit_ratehits, missesevents/s
cassandra.row_cache_utilizationusedpercentage
cassandra.row_cache_sizesizebytes
cassandra.key_cache_hit_ratiohit_ratiopercentage
cassandra.key_cache_hit_ratehits, missesevents/s
cassandra.key_cache_utilizationusedpercentage
cassandra.key_cache_sizesizebytes
cassandra.storage_live_disk_space_usedusedbytes
cassandra.compaction_completed_tasks_ratecompletedtasks/s
cassandra.compaction_pending_tasks_countpendingtasks
cassandra.compaction_compacted_ratecompactedbytes/s
cassandra.jvm_memory_usedheap, nonheapbytes
cassandra.jvm_gc_rateparnew, cmsgc/s
cassandra.jvm_gc_timeparnew, cmsseconds
cassandra.dropped_messages_ratedroppedmessages/s
cassandra.client_requests_timeouts_rateread, writetimeout/s
cassandra.client_requests_unavailables_rateread, writeexceptions/s
cassandra.client_requests_failures_rateread, writefailures/s
cassandra.storage_exceptions_ratestorageexceptions/s

Per thread pool

Metrics related to Cassandra's thread pools. Each thread pool provides its own set of the following metrics.

Labels:

LabelDescription
thread_poolthread pool name

Metrics:

MetricDimensionsUnit
cassandra.thread_pool_active_tasks_countactivetasks
cassandra.thread_pool_pending_tasks_countpendingtasks
cassandra.thread_pool_blocked_tasks_countblockedtasks
cassandra.thread_pool_blocked_tasks_rateblockedtasks/s

Alerts

There are no alerts configured by default for this integration.

Setup

Prerequisites

Configure 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.

Configuration

File

The configuration file name for this integration is go.d/cassandra.conf.

You can edit the configuration file using the edit-config script from the Netdata config directory.

cd /etc/netdata 2>/dev/null || cd /opt/netdata/etc/netdata
sudo ./edit-config go.d/cassandra.conf

Options

The following options can be defined globally: update_every, autodetection_retry.

Config options
NameDescriptionDefaultRequired
update_everyData collection frequency.5no
autodetection_retryRecheck interval in seconds. Zero means no recheck will be scheduled.0no
urlServer URL.http://127.0.0.1:7072/metricsyes
usernameUsername for basic HTTP authentication.no
passwordPassword for basic HTTP authentication.no
proxy_urlProxy URL.no
proxy_usernameUsername for proxy basic HTTP authentication.no
proxy_passwordPassword for proxy basic HTTP authentication.no
timeoutHTTP request timeout.2no
not_follow_redirectsRedirect handling policy. Controls whether the client follows redirects.nono
tls_skip_verifyServer certificate chain and hostname validation policy. Controls whether the client performs this check.nono
tls_caCertification authority that the client uses when verifying the server's certificates.no
tls_certClient TLS certificate.no
tls_keyClient TLS key.no

Examples

Basic

A basic example configuration.

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

HTTP authentication

Local server with basic HTTP authentication.

Config
jobs:
- name: local
url: http://127.0.0.1:7072/metrics
username: foo
password: bar

HTTPS with self-signed certificate

Local server with enabled HTTPS and self-signed certificate.

Config
jobs:
- name: local
url: https://127.0.0.1:7072/metrics
tls_skip_verify: yes

Multi-instance

Note: When you define multiple jobs, their names must be unique.

Collecting metrics from local and remote instances.

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

- name: remote
url: http://192.0.2.1:7072/metrics

Troubleshooting

Debug Mode

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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