Elasticsearch Notes

elasticsearch-head and elastic search plugin ( https://github.com/mobz/elasticsearch-head )

_search?search_type=count

{
 "aggs" : {
  "all_users": {
   "terms": {
    "field": "screen_name"
   }
  }
 }
}

list indexes and summary:

curl 'localhost:9200/_cat/indices?v'

show health

curl 'localhost:9200/_cat/health?v'

list nodes:

curl 'localhost:9200/_cat/nodes?v'

delete an index

curl -XDELETE 'http://localhost:9200/twitterindex_v2/'

created an index with mappings from a file:

curl -XPUT localhost:9200/twitterindex_v2 -T 'mapping.1'

get the mappoings for an index

curl -XGET "http://localhost:9200/test-index/_mapping" | jsonlint > mapping

pattern of data import

1. import data
2. dump mapping
3. edit mapping
4. create new index with new mapping
5. import data again.

Explicitly mapping date fields

from: http://joelabrahamsson.com/dynamic-mappings-and-dates-in-elasticsearch/

curl -XPUT "http://localhost:9200/myindex" -d'
{
   "mappings": {
      "tweet": {
         "date_detection": false,
         "properties": {
             "postDate": {
                 "type": "date"
             }
         }
      }
   }
}'

backup

from: https://www.elastic.co/guide/en/elasticsearch/guide/current/backing-up-your-cluster.html

add to the end of /etc/elasticsearch/elasticsearch.yml :

path.repo: ["/mnt/freenas/dataset_elasticsearch/backup"]

root@keres /mnt/freenas/dataset_elasticsearch/backup # curl -XPUT "http://localhost:9200/_snapshot/freenas_backup" -d'
{
    "type": "fs",
    "settings": {
        "location": "/mnt/freenas/dataset_elasticsearch/backup"
    }
}'

searches

{
  "query": { "match_all": {} }
}


{
  "query": { "match": { "filter_level": "low" } }
}


{
  "query": { "match": { "source": "iPad" } },
   "_source": [ "source" , "text"]
}

{
  "size": 0,
  "aggs": {
    "group_by_state": {
      "terms": {
        "field": "source"
      }
    }
  }
}

  "size": 0, - print agg only and not hits. PEROFORMANCE!!

changing-mapping-with-zero-downtime

https://www.elastic.co/blog/changing-mapping-with-zero-downtime

aggregates

https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-bucket-filters-aggregation.html

moving data between indexes

Use ElasticDump ( https://www.npmjs.com/package/elasticdump )

1) yum install epel-release

2) yum install nodejs

3) yum install nodejs npm

4) npm install elasticdump

5) cd node_modules/elasticdump/bin

6)

./elasticdump \

  --input=http://192.168.1.1:9200/original \

  --output=http://192.168.1.2:9200/newCopy \

  --type=data

elasticdump \
  --input=http://localhost:9700/.kibana \
  --output=http://localhost:9700/.kibana_read_only \
  --type=mapping
elasticdump \
  --input=http://localhost:9700/.kibana \
  --output=http://localhost:9700/.kibana_read_only \
  --type=data

serverconfig notes

stuff I've added to my default config:

# for backups
path.repo: ["/mnt/freenas/dataset_elasticsearch/backup"]
# to disallow remote code execution
script.disable_dynamic: true

/etc/sysconfig/sysconfig/elasticsearch ( grep -v ^# )

DATA_DIR=/data/elasticsearch/data
LOG_DIR=/data/elasticsearch/log
WORK_DIR=data/elasticsearch/tmp
ES_HEAP_SIZE=2g
ES_GC_LOG_FILE=/data/elasticsearch/log/gc.log