README
¶
Cassandra collector
Overview
Cassandra is an open-source NoSQL database management system.
This collector gathers metrics from one or more Cassandra servers, depending on your configuration.
Collected 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.
global
The metrics apply to the entire monitored application.
This scope has no labels.
Metrics:
| Metric | Dimensions | Unit |
|---|---|---|
| cassandra.client_requests_rate | read, write | requests/s |
| cassandra.client_request_read_latency_histogram | p50, p75, p95, p98, p99, p999 | seconds |
| cassandra.client_request_write_latency_histogram | p50, p75, p95, p98, p99, p999 | seconds |
| cassandra.client_requests_latency | read, write | seconds |
| cassandra.row_cache_hit_ratio | hit_ratio | percentage |
| cassandra.row_cache_hit_rate | hits, misses | events/s |
| cassandra.row_cache_utilization | used | percentage |
| cassandra.row_cache_size | size | bytes |
| cassandra.key_cache_hit_ratio | hit_ratio | percentage |
| cassandra.key_cache_hit_rate | hits, misses | events/s |
| cassandra.key_cache_utilization | used | percentage |
| cassandra.key_cache_size | size | bytes |
| cassandra.storage_live_disk_space_used | used | bytes |
| cassandra.compaction_completed_tasks_rate | completed | tasks/s |
| cassandra.compaction_pending_tasks_count | pending | tasks |
| cassandra.compaction_compacted_rate | compacted | bytes/s |
| cassandra.jvm_memory_used | heap, nonheap | bytes |
| cassandra.jvm_gc_rate | parnew, cms | gc/s |
| cassandra.jvm_gc_time | parnew, cms | seconds |
| cassandra.dropped_messages_rate | dropped | messages/s |
| cassandra.client_requests_timeouts_rate | read, write | timeout/s |
| cassandra.client_requests_unavailables_rate | read, write | exceptions/s |
| cassandra.client_requests_failures_rate | read, write | failures/s |
| cassandra.storage_exceptions_rate | storage | exceptions/s |
thread pool
Metrics related to Cassandra's thread pools. Each thread pool provides its own set of the following metrics.
Labels:
| Label | Description |
|---|---|
| thread_pool | thread pool name |
Metrics:
| Metric | Dimensions | Unit |
|---|---|---|
| cassandra.thread_pool_active_tasks_count | active | tasks |
| cassandra.thread_pool_pending_tasks_count | pending | tasks |
| cassandra.thread_pool_blocked_tasks_count | blocked | tasks |
| cassandra.thread_pool_blocked_tasks_rate | blocked | tasks/s |
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.shJVM_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 is go.d/cassandra.conf.
The file format is YAML. Generally the format is:
update_every: 1
autodetection_retry: 0
jobs:
- name: some_name1
- name: some_name1
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
| Name | Description | Default | Required |
|---|---|---|---|
| update_every | Data collection frequency. | 5 | |
| autodetection_retry | Re-check interval in seconds. Zero means not to schedule re-check. | 0 | |
| url | Server URL. | http://127.0.0.1:7072/metrics | yes |
| username | Username for basic HTTP authentication. | ||
| password | Password for basic HTTP authentication. | ||
| proxy_url | Proxy URL. | ||
| proxy_username | Username for proxy basic HTTP authentication. | ||
| proxy_password | Password for proxy basic HTTP authentication. | ||
| timeout | HTTP request timeout. | 2 | |
| not_follow_redirects | Redirect handling policy. Controls whether the client follows redirects. | no | |
| tls_skip_verify | Server certificate chain and hostname validation policy. Controls whether the client performs this check. | no | |
| tls_ca | Certification authority that the client uses when verifying the server's certificates. | ||
| tls_cert | Client TLS certificate. | ||
| tls_key | Client TLS key. |
Examples
A basic example configuration.
Config
jobs:
- name: local
url: http://127.0.0.1:7072/metrics
Local server with basic HTTP authentication.
Config
jobs:
- name: local
url: http://127.0.0.1:7072/metrics
username: foo
password: bar
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
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.ddirectory, usually at/usr/libexec/netdata/plugins.d/. If that's not the case on your system, opennetdata.confand look for thepluginssetting under[directories].cd /usr/libexec/netdata/plugins.d/ -
Switch to the
netdatauser.sudo -u netdata -s -
Run the
go.d.pluginto debug the collector:./go.d.plugin -d -m cassandra
Documentation
Source Files