Distributed Installation

A distributed installation runs ALEC as a service on top of Sentinel, an OpenNMS component that enables scalability for data processing.

Figure 1. Example distributed installation network architecture

Prerequisites

In addition to an existing instance of OpenNMS Horizon 30.0.1 or newer, these instructions assume that you have the following:

• A Kafka broker (or cluster) running Kafka 0.11.x or greater.

• One or more active Minions.

• OpenNMS Sentinel.

• Minions configured to use Kafka for the transport.

OpenNMS configuration

Complete the following steps in the OpenNMS Karaf shell. They configure your OpenNMS instance in preparation for a distributed installation of ALEC.

Configure Kafka Producer to point to your Kafka broker:
``echo 'bootstrap.servers=127.0.0.1:9092' > "$OPENNMS_HOME/etc/org.opennms.features.kafka.producer.client.cfg"`` Disable incremental alarm suppression: ``echo 'suppressIncrementalAlarms=false' >> "$OPENNMS_HOME/etc/org.opennms.features.kafka.producer.cfg"``

Open `$OPENNMS_HOME/etc/org.apache.karaf.features.cfg` in a text editor and add `opennms-kafka-producer` to the `featuresBoot` property. Enable consumption of Kafka events: ``echo 'org.opennms.netmgt.eventd.sink.enable=true' > "$OPENNMS_HOME/etc/opennms.properties.d/event-sink.properties"``
 This procedure assumes that you are already using the Kafka strategy for the Sink API (see Prerequisites).

Install ALEC in OpenNMS

You must complete the pre-installation tasks before proceeding with the installation.

Make sure that you install the package repository on all systems that are running Sentinel and OpenNMS.

Install the ALEC plugin package on your OpenNMS server:
``yum -y install opennms-alec-plugin``
Configure the feature set to be installed when OpenNMS starts:
``echo 'alec-opennms-distributed wait-for-kar=opennms-alec-plugin' > "$OPENNMS_HOME/etc/featuresBoot.d/alec.boot"`` Install ALEC in Sentinel Install the ALEC plugin package on your Sentinel systems: ``yum -y install sentinel-alec-plugin`` Configure Kafka Stream (consumer): ``````echo 'bootstrap.servers=127.0.0.1:9092 commit.interval.ms=5000' > "$SENTINEL_HOME/etc/org.opennms.alec.datasource.opennms.kafka.streams.cfg"``````
Configure the Kafka producer:
``echo 'bootstrap.servers=127.0.0.1:9092' > "$SENTINEL_HOME/etc/org.opennms.alec.datasource.opennms.kafka.producer.cfg"``  Kafka Stream reads alarms and inventory, while the Kafka producer sends events. Configure ZooKeeper for distributed coordination: ``echo 'connectString=127.0.0.1:2181' > "$SENTINEL_HOME/etc/org.opennms.features.distributed.coordination.zookeeper.cfg"``
Configure the feature set to be installed when Sentinel starts:
``````echo 'sentinel-core
sentinel-coordination-zookeeper
alec-sentinel-distributed wait-for-kar=opennms-alec-plugin' >> "\$SENTINEL_HOME/etc/featuresBoot.d/alec.boot"``````

1. Restart OpenNMS and Sentinel.

2. Make sure that the required Kafka topics have been created (see Kafka topics).

3. Run the `health:check` command in an OpenNMS Karaf shell to check the status of your OpenNMS instance.

4. Run the `health:check` command in a Sentinel Karaf shell to check the status of the Sentinel instance.

• Repeat this step for each Sentinel instance in your environment.

5. Run the `opennms-alec:list-graphs` command in a Sentinel Karaf shell to enumerate all available graphs.

At this point, the health check commands should return with no issues, and one graph named "dbscan" should be enumerated:

``````admin@opennms> opennms-alec:list-graphs
dbscan: 0 situations on 524 vertices and 4 edges.``````
 Your graph may not have any situations, vertices, or edges at this point. This is normal during initial setup.