Memcached
Memcached
Plugin: python.d.plugin Module: memcached
Overview
Monitor Memcached metrics for proficient in-memory key-value store operations. Track cache hits, misses, and memory usage for efficient data caching.
It reads server response to stats command (stats interface).
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
If no configuration is given, collector will attempt to connect to memcached instance on 127.0.0.1:11211 address.
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
No action required.
Configuration
File
The configuration file name for this integration is python.d/memcached.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 python.d/memcached.conf
Options
There are 2 sections:
- Global variables
- One or more JOBS that can define multiple different instances to monitor.
The following options can be defined globally: priority, penalty, autodetection_retry, update_every, but can also be defined per JOB to override the global values.
Additionally, the following collapsed table contains all the options that can be configured inside a JOB definition.
Every configuration JOB starts with a job_name value which will appear in the dashboard, unless a name parameter is specified.
| Name | Description | Default | Required |
|---|---|---|---|
| host | the host to connect to. | 127.0.0.1 | False |
| port | the port to connect to. | 11211 | False |
| update_every | Sets the default data collection frequency. | 10 | False |
| priority | Controls the order of charts at the netdata dashboard. | 60000 | False |
| autodetection_retry | Sets the job re-check interval in seconds. | 0 | False |
| penalty | Indicates whether to apply penalty to update_every in case of failures. | yes | False |
| name | Job name. This value will overwrite the job_name value. JOBS with the same name are mutually exclusive. Only one of them will be allowed running at any time. This allows autodetection to try several alternatives and pick the one that works. |
False |
Examples
localhost
An example configuration for localhost.
localhost:
name: 'local'
host: 'localhost'
port: 11211
localipv4
An example configuration for localipv4.
localhost:
name: 'local'
host: '127.0.0.1'
port: 11211
localipv6
An example configuration for localipv6.
localhost:
name: 'local'
host: '::1'
port: 11211
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 Memcached instance
These metrics refer to the entire monitored application.
This scope has no labels.
Metrics:
| Metric | Dimensions | Unit |
|---|---|---|
| memcached.cache | available, used | MiB |
| memcached.net | in, out | kilobits/s |
| memcached.connections | current, rejected, total | connections/s |
| memcached.items | current, total | items |
| memcached.evicted_reclaimed | reclaimed, evicted | items |
| memcached.get | hints, misses | requests |
| memcached.get_rate | rate | requests/s |
| memcached.set_rate | rate | requests/s |
| memcached.delete | hits, misses | requests |
| memcached.cas | hits, misses, bad value | requests |
| memcached.increment | hits, misses | requests |
| memcached.decrement | hits, misses | requests |
| memcached.touch | hits, misses | requests |
| memcached.touch_rate | rate | requests/s |
Alerts
The following alerts are available:
| Alert name | On metric | Description |
|---|---|---|
| memcached_cache_memory_usage | memcached.cache | cache memory utilization |
| memcached_cache_fill_rate | memcached.cache | average rate the cache fills up (positive), or frees up (negative) space over the last hour |
| memcached_out_of_cache_space_time | memcached.cache | estimated time the cache will run out of space if the system continues to add data at the same rate as the past hour |
Troubleshooting
Debug Mode
To troubleshoot issues with the memcached collector, run the python.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
python.d.pluginto debug the collector:./python.d.plugin memcached debug trace