Cassandra
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:
- http://127.0.0.1:7072/metrics
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.
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 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.
| Name | Description | Default | Required |
|---|---|---|---|
| update_every | Data collection frequency. | 5 | no |
| autodetection_retry | Recheck interval in seconds. Zero means no recheck will be scheduled. | 0 | no |
| url | Server URL. | http://127.0.0.1:7072/metrics | yes |
| username | Username for basic HTTP authentication. | no | |
| password | Password for basic HTTP authentication. | no | |
| proxy_url | Proxy URL. | no | |
| proxy_username | Username for proxy basic HTTP authentication. | no | |
| proxy_password | Password for proxy basic HTTP authentication. | no | |
| timeout | HTTP request timeout. | 2 | no |
| not_follow_redirects | Redirect handling policy. Controls whether the client follows redirects. | no | no |
| tls_skip_verify | Server certificate chain and hostname validation policy. Controls whether the client performs this check. | no | no |
| tls_ca | Certification authority that the client uses when verifying the server’s certificates. | no | |
| tls_cert | Client TLS certificate. | no | |
| tls_key | Client 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.
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.
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.
jobs:
- name: local
url: http://127.0.0.1:7072/metrics
- name: remote
url: http://192.0.2.1:7072/metrics
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:
| 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 |
Per 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 |
Alerts
There are no alerts configured by default for this integration.
Troubleshooting
Debug Mode
Important: Debug mode is not supported for data collection jobs created via the UI using the Dyncfg feature.
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
Getting Logs
If you’re encountering problems with the cassandra collector, follow these steps to retrieve logs and identify potential issues:
- Run the command specific to your system (systemd, non-systemd, or Docker container).
- Examine the output for any warnings or error messages that might indicate issues. These messages should provide clues about the root cause of the problem.
System with systemd
Use the following command to view logs generated since the last Netdata service restart:
journalctl _SYSTEMD_INVOCATION_ID="$(systemctl show --value --property=InvocationID netdata)" --namespace=netdata --grep cassandra
System without systemd
Locate the collector log file, typically at /var/log/netdata/collector.log, and use grep to filter for collector’s name:
grep cassandra /var/log/netdata/collector.log
Note: This method shows logs from all restarts. Focus on the latest entries for troubleshooting current issues.
Docker Container
If your Netdata runs in a Docker container named “netdata” (replace if different), use this command:
docker logs netdata 2>&1 | grep cassandra