Newts

Newts is a time-series data schema for Apache Cassandra. It enables horizontal scaling capabilities for your time series storage and is an alternative to JRobin and RRDtool.

The Cassandra cluster design, setup, sizing, tuning and operation is out of scope for this section. To install and set up a Cassandra cluster please follow the Cassandra installation instructions. For further information see Cassandra Getting Started Guide.

To avoid unwanted updates and disable the Cassandra repository on DNF/YUM based distributions or use apt-mark hold cassandra on APT based distributions.
For simplicity we use the ${OPENNMS_HOME}/bin/newts init command which initializes a Newts keyspace for you and the defaults are not optimal tuned for a production-ready environment. If you want to build a production environment please consult Sizing Cassandra for Newts and planning Anti-patterns in Cassandra articles.

Objectives

  • Configure Meridian to use an existing Cassandra cluster

  • Initializing the Newts keyspace using newts init with STCS without production-ready tuning

  • Verify time series data is stored and can be accessed

Before you begin

  • A running instance of Meridian running on Linux

  • Working data collection and response time metrics from Collectd and Pollerd

  • Cassandra cluster with access to the Cassandra client port 9042/tcp

Configurations has to be made in the etc directory relative to the Meridian Core home directory. Depending on your operating system the home directory is /usr/share/opennms for Debian/Ubuntu or /opt/opennms for CentOS/RHEL.

Configure Meridian Core using Newts

Create a configuration file with the time series storage settings
sudo vi etc/opennms.properties.d/timeseries.properties
Configure the Newts as the time series strategy
# Configure storage strategy
org.opennms.rrd.storeByForeignSource=true(1)
org.opennms.timeseries.strategy=newts(2)

# Configure Newts time series storage connection
org.opennms.newts.config.hostname={cassandra-ip1,cassandra-ip2}(3)
org.opennms.newts.config.keyspace=newts(4)
org.opennms.newts.config.port=9042(5)

# One year in seconds
org.opennms.newts.config.ttl=31540000(6)

# Seven days in seconds
org.opennms.newts.config.resource_shard=604800(7)
1 Associate time series data by the foreign ID instead of the database generated Node-ID.
2 Set time-series strategy to use newts.
3 Host or IP addresses of the Cassandra cluster nodes. Can be a comma-separated list.
4 Name of the keyspace which is initialized and used.
5 Port to connect to Cassandra.
6 Retention rate for the time series data.
7 Shard metrics every 7 days.
Initialize the Newts schema in Cassandra
bin/newts init
Connect to Cassandra with the CQL shell
cd ${CASSANDRA_HOME}/bin
./cqlsh
Verify if the keyspace was properly initialized
use newts;
describe table terms;
describe table samples;
Apply changes and verify your configuration
systemctl restart opennms

With this infomration set, Meridian will begin persisting metrics using the Newts engine when restarted.

Go to the Node detail page from a SNMP-managed device and verify that you see response time graphs for ICMP and node-level performance data.