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How to install Elasticsearch on ClearOS

Elasticsearch is a search server. This is useful once your project is quite big and you start hitting limits of the default search in Tiki Wiki CMS Groupware. Elasticsearch integrates well with Kibana. See also: How to install Kibana on ClearOS

Status as of 2018-04-28: Elasticsearch is at v5.6.8 . There are some minor issues with Adminer, which are being looked into.

How to install

On ClearOS 7.x
yum install app-elasticsearch


Comments: RAM: You need at least 3 GB of system RAM to run Elasticsearch (1 gig for ClearOS and 2 gigs for Elasticsearch). A warning message is shown in webconfig if the requirement is not met. If you are just hacking around, you can change the default Elasticsearch usage from 2 GB to 1 GB. To do so, update the following options in /etc/elasticsearch/jvm.options:
-Xms1g
-Xmx1g

Then, visit https://example.org:81/app/elasticsearch and activate it
2018 04 28 Start Elasticsearch After Installation

Example of install log

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How to upgrade

How to upgrade
yum upgrade app-elasticsearch elasticsearch adminer-elasticsearch

From 2.x to 5.x


When running Elasticsearch with small amount of memory, the service may not start properly. Even using the hack above, Elasticsearch will die when indexing documents. So it is better to have at least 4gb RAM on server running Elasticsearch. When upgrading elasticsearch and also the server memory, these steps may be useful:

1. Set -Xms2g -Xmx3g on /etc/elasticsearch/jvm.options
2. Restart elasticsearch by typing systemctl restart elasticsearch
3. Destroy old indexes by curl -XDELETE localhost:9200/tiki_ppm16_main_5af2f8481bb8b (You need to find the name of your old indexes. You can also use the Adminer interface linked from your Elasticsearch app for ClearOS (https://example.org:81/app/elasticsearch)
4. Increase Tiki preference Search index rebuild memory limit to 2G
5. Rebuild the index by using php console.php index:rebuild -vvv
6. Clear all caches php console.php cache:clear

When index name is not known, it can be found on Tiki instance, at page http://example.org/tiki-admin.php?page=search. Also, you can list all your indexes by typing curl 'localhost:9200/_cat/indices' .

Full install log example

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Key points

  • Web interface is at https://example.org:81/app/elasticsearch
    • View your data via Adminer Most things are working with Adminer 4.6.2 but data edits are not yet working as of 2018-04-28
  • By default, Elasticsearch only listens to localhost. Do not change this unless you know what you are doing. If you do so, make sure http://example.org:9200 does not answer to unauthorized users or systems. If it does, you need to configure the firewall. Potential future todo: tighten this up even more by password protecting connections from localhost.
  • By defaut, it's set to auto restart on each boot
  • As of 2016-11-24, it's installing Elasticsearch 2.x, but the plan is to offer 5.x as soon as Tiki is confirmed working with it. 2017-04-21: Now that recent versions of Tiki (which ones?) support Elasticsearch 5.x the app will upgrade to 5.x in May or June 2017.
  • Elasticsearch 1.x is known to have issues with some of the advanced features of trackers, so it's not supported.
  • Elasticsearch can require a lot of RAM if you have a lot data.
  • Upgrades to major versions will happen according to the Tiki requirements. Ex.: support for 6.x will only be added once Tiki supports it.

To test

Wait a few minutes after the initial install. Then you can check if all is okay.

Test if Elasticsearch is running
[root@example ~]# curl localhost:9200
{
  "name" : "Chtylok",
  "cluster_name" : "elasticsearch",
  "cluster_uuid" : "UmE4ikI2Q3eM5ik7kbkkdg",
  "version" : {
    "number" : "2.4.1",
    "build_hash" : "c67dc32e24162035d18d6fe1e952c4cbcbe79d16",
    "build_timestamp" : "2016-09-27T18:57:55Z",
    "build_snapshot" : false,
    "lucene_version" : "5.5.2"
  },
  "tagline" : "You Know, for Search"
}


How to configure with Tiki

  1. In your Tiki instance, at tiki-admin.php?page=search -> Advanced Search -> Unified Search Engine -> Elasticsearch (All the other default settings work out of the box)
    • You may need to set your "Preference Filters" to include "Advanced"
  2. To test, click "Rebuild Index"
  3. Optional but recommended, add the rebuild command to a daily cron job
    php console.php index:rebuild