MemcachedMonitor

Monitors Memcached, a distributed memory object caching system. To monitor the service availability, the monitor tests if it can request the Memcached statistics. The statistics are processed and stored in RRD files. The following metrics are collected:

Table 1. Collected metrics using the MemcachedMonitor
Metric	Description
uptime	Seconds the Memcached server has been running since last restart.
rusageuser	User time seconds for the server process.
rusagesystem	System time seconds for the server process.
curritems	Number of items in this server’s cache.
totalitems	Number of items stored on this server.
bytes	Number of bytes currently used for caching items.
limitmaxbytes	Maximum configured cache size.
currconnections	Number of open connections to this Memcached.
totalconnections	Number of successful connect attempts to this server since start.
connectionstructure	Number of internal connection handles currently held by the server.
cmdget	Number of GET commands received since server startup.
cmdset	Number of SET commands received since server startup.
gethits	Number of successful GET commands (cache hits) since startup.
getmisses	Number of failed GET requests, because nothing was cached.
evictions	Number of objects removed from the cache to free up memory.
bytesread	Number of bytes received from the network.
byteswritten	Number of bytes sent to the network.
threads	Number of threads this server used.

Monitor facts

Class Name

org.opennms.netmgt.poller.monitors.MemcachedMonitor

Configuration and use

Table 2. Optional monitor-specific parameters for the MemcachedMonitor
Parameter	Description	Default
retry	Number of attempts to establish the Memcached connection.	0
port	TCP port connecting to Memcached.	11211

This monitor implements the Common Configuration Parameters.

Examples

The following example shows a configuration in poller-configuration.xml.

Example uses CentOS/RHEL path name. For Debian/Ubuntu, use /var/lib/opennms/rrd/response.

Note that you must include the monitor section in your definition.

<service name="Memcached" interval="300000" user-defined="false" status="on">
  <parameter key="port" value="11211" />
  <parameter key="retry" value="2" />
  <parameter key="timeout" value="3000" />
  <parameter key="rrd-repository" value="/opt/opennms/share/rrd/response" />
  <parameter key="ds-name" value="memcached" />
  <parameter key="rrd-base-name" value="memcached" />
</service>

<monitor service="Memcached" class-name="org.opennms.netmgt.poller.monitors.MemcachedMonitor" />