metron-platform/metron-indexing/README.md

# Indexing

## Introduction

The `indexing` topology is a topology dedicated to taking the data
from the enrichment topology that have been enriched and storing the data in one or more supported indices
* HDFS as rolled text files, one JSON blob per line
* Elasticsearch
* Solr

By default, this topology writes out to both HDFS and one of
Elasticsearch and Solr.

Indices are written in batch and the batch size is specified in the
[Sensor Indexing Configuration](#sensor-indexing-configuration) via the `batchSize` parameter.
This config is variable by sensor type.

## Indexing Architecture

![Architecture](indexing_arch.png)

The indexing topology is extremely simple.  Data is ingested into kafka
and sent to 
* An indexing bolt configured to write to either elasticsearch or Solr
* An indexing bolt configured to write to HDFS under `/apps/metron/enrichment/indexed`

By default, errors during indexing are sent back into the `indexing` kafka queue so that they can be indexed and archived.

## Sensor Indexing Configuration
The sensor specific configuration is intended to configure the
indexing used for a given sensor type (e.g. `snort`).  

Just like the global config, the format is a JSON stored in zookeeper and on disk at `$METRON_HOME/config/zookeeper/indexing`.  Within the sensor-specific configuration, you can configure the individual writers.  The writers currently supported are:
* `elasticsearch`
* `hdfs`
* `solr`

Depending on how you start the indexing topology, it will have either
elasticsearch or solr and hdfs writers running.

The configuration for an individual writer-specific configuration is a JSON map with the following fields:
* `index` : The name of the index to write to (defaulted to the name of the sensor).
* `batchSize` : The size of the batch that is written to the indices at once (defaulted to `1`).
* `enabled` : Whether the writer is enabled (default `true`).

### Indexing Configuration Examples
For a given  sensor, the following scenarios would be indicated by
the following cases:
#### Base Case
```
{
}
```
or no file at all.

* elasticsearch writer
  * enabled
  * batch size of 1
  * index name the same as the sensor
* hdfs writer
  * enabled
  * batch size of 1
  * index name the same as the sensor

If a writer config is unspecified, then a warning is indicated in the
Storm console.  e.g.:
`WARNING: Default and (likely) unoptimized writer config used for hdfs writer and sensor squid`

#### Fully specified
```
{
   "elasticsearch": {
      "index": "foo",
      "batchSize" : 100,
      "enabled" : true 
    },
   "hdfs": {
      "index": "foo",
      "batchSize": 1,
      "enabled" : true
    }
}
```
* elasticsearch writer
  * enabled
  * batch size of 100
  * index name of "foo"
* hdfs writer
  * enabled
  * batch size of 1
  * index name of "foo"

#### HDFS Writer turned off
```
{
   "elasticsearch": {
      "index": "foo",
      "enabled" : true 
    },
   "hdfs": {
      "index": "foo",
      "batchSize": 100,
      "enabled" : false
    }
}
```
* elasticsearch writer
  * enabled
  * batch size of 1
  * index name of "foo"
* hdfs writer
  * disabled

# Notes on Performance Tuning

Default installed Metron is untuned for production deployment.  By far
and wide, the most likely piece to require TLC from a performance
perspective is the indexing layer.  An index that does not keep up will
back up and you will see errors in the kafka bolt.  There
are a few knobs to tune to get the most out of your system.

## Kafka Queue
The `indexing` kafka queue is a collection point from the enrichment
topology.  As such, make sure that the number of partitions in
the kafka topic is sufficient to handle the throughput that you expect.

## Indexing Topology
The `indexing` topology as started by the `$METRON_HOME/bin/start_elasticsearch_topology.sh` 
or `$METRON_HOME/bin/start_solr_topology.sh`
script uses a default of one executor per bolt.  In a real production system, this should 
be customized by modifying the flux file in
`$METRON_HOME/flux/indexing/remote.yaml`. 
* Add a `parallelism` field to the bolts to give Storm a parallelism
  hint for the various components.  Give bolts which appear to be bottlenecks (e.g. the indexing bolt) a larger hint.
* Add a `parallelism` field to the kafka spout which matches the number of partitions for the enrichment kafka queue.
* Adjust the number of workers for the topology by adjusting the 
  `topology.workers` field for the topology. 

Finally, if workers and executors are new to you or you don't know where
to modify the flux file, the following might be of use to you:
* [Understanding the Parallelism of a Storm Topology](http://www.michael-noll.com/blog/2012/10/16/understanding-the-parallelism-of-a-storm-topology/)
* [Flux Docs](http://storm.apache.org/releases/current/flux.html)

## Zeppelin Notebooks
Zeppelin notebooks can be added to `/src/main/config/zeppelin/` (and subdirectories can be created for organization).  The placed files must be .json files and be named appropriately.
These files must be added to the metron.spec file and the RPMs rebuilt to be available to be loaded into Ambari.

The notebook files will be found on the server in `$METRON_HOME/config/zeppelin`

The Ambari Management Pack has a custom action to load these templates, ZEPPELIN_DASHBOARD_INSTALL, that will import them into Zeppelin.