Resource Types

Meridian uses resource types to group sets of performance data measurements for persisting, indexing, and displaying in the web UI. Each resource type has a unique name, label definitions for display in the UI, and strategy definitions for archiving the measurements for long-term analysis.

There are two labels for a resource type. The first, label, defines a string to display in the UI. The second, resourceLabel, defines the template used when displaying each unique group of measurements name for the resource type.

There are two types of strategy definitions for resource types: the persistence selector strategy, and the storage strategy. The persistence selector strategy filters the group indexes down to a subset for storage on disk. The storage strategy converts an index into a resource path label for persistence.

Two resource types do not have a resource-type definition: node and ifIndex.

You can define resource types by placing files in either ${OPENNMS_HOME}/etc/resource-types.d or ${OPENNMS_HOME}/etc/datacollection. The latter file path is specific to SNMP.

Example diskIOIndex resource type definition from ${OPENNMS_HOME}/etc/datacollection/netsnmp.xml
<resourceType name="diskIOIndex" label="Disk IO (UCD-SNMP MIB)" resourceLabel="${diskIODevice} (index ${index})">
  <persistenceSelectorStrategy class="org.opennms.netmgt.collection.support.PersistRegexSelectorStrategy">
    <parameter key="match-expression" value="not(#diskIODevice matches '^(loop|ram).*')" />
  </persistenceSelectorStrategy>
  <storageStrategy class="org.opennms.netmgt.dao.support.SiblingColumnStorageStrategy">
    <parameter key="sibling-column-name" value="diskIODevice" />
    <parameter key="replace-all" value="s/^-//" />
    <parameter key="replace-all" value="s/\s//" />
    <parameter key="replace-all" value="s/:\\.*//" />
  </storageStrategy>
</resourceType>

Persistence selector strategies

You can configure the following persistence selector strategies to specify how to archive performance metrics:

Class Description

org.opennms.netmgt.collection.support.PersistAllSelectorStrategy

Persist all indexes.

org.opennms.netmgt.collection.support.PersistRegexSelectorStrategy

Persist indexes based on JEXL evaluation.
This class takes a single parameter, match-expression, which defines a JEXL expression. On evaluation, this expression should return either true (persist index to storage) or false (discard data). Note that match-expression works only on string attributes.

Storage strategies

You can configure the following storage strategies to specify how to store performance metrics long-term:

Class Storage Path Value

org.opennms.netmgt.collection.support.IndexStorageStrategy

Index

org.opennms.netmgt.collection.support.JexlIndexStorageStrategy

Value after JexlExpression evaluation.

org.opennms.netmgt.collection.support.ObjectNameStorageStrategy

Value after JexlExpression evaluation.

org.opennms.netmgt.dao.support.FrameRelayStorageStrategy

Interface label + '.' + DLCI

org.opennms.netmgt.dao.support.HostFileSystemStorageStrategy

Uses the value from the hrStorageDescr column in the hrStorageTable, cleaned to make a valid directory name on supported file systems.

org.opennms.netmgt.dao.support.SiblingColumnStorageStrategy

Uses the value from an SNMP lookup of OID in the sibling-column-name parameter, cleaned to make a valid directory name on supported file systems.

org.opennms.protocols.xml.collector.XmlStorageStrategy

Index, cleaned to make a valid directory name on supported file systems.

JexlIndexStorageStrategy

The JexlIndexStorageStrategy class takes two parameters: index-format, which is required, and clean-output, which is optional.

JexlIndexStorageStrategy parameters
Parameter Description

index-format

The JexlExpression to evaluate.

clean-output

Boolean which indicates whether the index value is cleaned up.

If the index value is set to be cleaned up, it will have all whitespace, colons (:), forward and back slashes (/, \), and vertical bars (|) replaced with underscores (_). All equal signs (=) will be removed.

To extend this class and create custom storage strategies, you can override the updateContext method and set additional key/value pairs to use in your index-format template.

Example custom storage strategy definition
public class ExampleStorageStrategy extends JexlIndexStorageStrategy {

    private static final Logger LOG = LoggerFactory.getLogger(ExampleStorageStrategy.class);
    public ExampleStorageStrategy() {
        super();
    }

    @Override
    public void updateContext(JexlContext context, CollectionResource resource) {
        context.set("Example", resource.getInstance());
    }
}

ObjectNameStorageStrategy

The ObjectNameStorageStrategy extends the JexlIndexStorageStrategy and, as such, its requirements are the same. Extra key/value pairs are added to the JexlContext, which can then be used in the index-format template.

The original index string is converted to an ObjectName and can be referenced as ${objectname}. The domain from the ObjectName can be referenced as ${domain}. All key properties from the ObjectName can also be referenced by using ${key}.

You can use this storage strategy with JMX MBean data collections where multiple MBeans can return the same set of attributes.

As of OpenNMS Horizon 20, this is supported only when using an HTTP-to-JMX proxy; using the XmlCollector as the JmxCollector does not yet support indexed groups.
Example storage storage strategy used with JMX MBean
<storageStrategy class="org.opennms.netmgt.collection.support.ObjectNameStorageStragegy">
  <parameter key="index-format" value="$\{domain}_${type}_$\{name}" />
  <parameter key="clean-output" value="true" />
</storageStrategy>

In this example, passing an MBean through this storage strategy produces a clean index value (for example, java.lang:type=MemoryPool,name=Survivor Space will become java_lang_MemoryPool_Survivor_Space).

HostFileSystemStorageStrategy

The HostFileSystemStorageStrategy class takes no parameters and is marked as deprecated. You should replace it with the following definition:

SiblingColumnStorageStrategy class definition
<storageStrategy class="org.opennms.netmgt.dao.support.SiblingColumnStorageStrategy">
  <parameter key="sibling-column-name" value="hrStorageDescr" />
  <parameter key="replace-first" value="s/^-$/_root_fs/" />
  <parameter key="replace-all" value="s/^-//" />
  <parameter key="replace-all" value="s/\\s//" />
  <parameter key="replace-all" value="s/:\\\\.*//" />
</storageStrategy>

SiblingColumnStorageStrategy

The SiblingColumnStorageStrategy class replaces HostFileSystemStorageStrategy, which is deprecated. It takes the following parameters:

Parameter Description

sibling-column-name

Name of another mibObj in the same group. This string value forms the starting point for the index.

replace-first

Specifies a regex replacement to perform against the value of the object that sibling-column-name points to. Only the first match in the input is replaced.

replace-all

Specifies a global regex replacement to perform against the value of the object that sibling-column-name points to. Every match in the input is replaced.

Values for replace-first and replace-all must match the following pattern: s/regex/replacement/. If they do not, an error will be thrown.

XmlStorageStrategy

The XmlStorageStrategy class takes no parameters. Its index value will have all whitespace, colons (:), forward and back slashes (/, \), and vertical bars (|) replaced with underscores (_). All equal signs (=) will be removed.