Elasticsearch is a search server based on Lucene. It provides a
distributed, multitenant-capable full-text search engine with a
RESTful web interface and schema-free JSON documents. This package
contains the infrastructure needed to an ElasticSearch node.
This ElasticSearch charm is for 99% based on the charm of James Beedy.
What we have changed is the extra_bindings settings and which IP the charm now
distribute over its relation. It only uses the machine's private IP. We noticed
problems while deploying the ELK stack on GCE. It uses the FAN IP addresses to
pass over the client relation, however the client (Kibana in this case) couldn't
Elasticsearch is a flexible and powerful open source, distributed, real-time
search and analytics engine. Architected from the ground up for use in
distributed environments where reliability and scalability are must haves,
Elasticsearch gives you the ability to move easily beyond simple full-text
search. Through its robust set of APIs and query DSLs, plus clients for the
most popular programming languages, Elasticsearch delivers on the near
limitless promises of search technology.
Excerpt from elasticsearch.org
This charm can be used to deploy Elasticsearch in any way that is suppored by upstream Elasticsearch, and then some.
The charm configuration exposes an option called node-type, which is used by the charm to know what type of
Elasticsearch node to configure. In order to orchestrate this charm to facilitate more complex deployments,
you must configure the node-type on a per application basis.
The options for the node-type config can be explained as follows:
all - The node will assume all roles of Elasticsearch, there will be no difference in configuration from one node to the next.
master - The node will assume the 'master' node-type. Master nodes will wait for the number of peers to be >= the charm configuration
option minn-master-count (this defaults to 1) before bootstrapping the cluster.
coordinator - The node will assume the 'coordinator' node-type. Coordinator nodes will wait until they have a relation to the master before
joining the cluster.
data - The node will assume the 'data' node-type. Data nodes will wait until they have a relation to the master before
joining the cluster.
ingest - The node will assume the 'ingest' node-type. Ingest nodes will wait until they have a relation to the master before
joining the cluster.
This charm supports Juju storage (as of Juju 2.3).
To deploy this charm using Juju storage (most common for data nodes)
juju deploy elasticsearch --storage data=ebs,10G
Following deployment, we can see the attached volume, and that is being used for Elasticsearch data:
$ df -h | grep elasticsearch
/dev/xvdf1 9.8G 23M 9.2G 1% /srv/elasticsearch-data
$ ls -la /srv/elasticsearch-data
drwxr-xr-x 4 elasticsearch elasticsearch 4096 Oct 30 21:53 .
drwxr-xr-x 3 root root 4096 Oct 30 21:49 ..
drwx------ 2 elasticsearch elasticsearch 16384 Oct 30 21:49 lost+found
drwxr-xr-x 3 elasticsearch elasticsearch 4096 Oct 30 21:53 nodes
Deploying this charm with the defaults will get you Elasticsearch installed from the elastic.co apt sources, and an all-in-one node-type, where
each unit is every node type.
juju deploy elasticsearch -n 3
The above command would deploy 3 elasticsearch nodes, of which all are master, data, ingest, and coordinator.
This functionality mirrors that of the legacy Juju Elasticsearch charm, you can deploy and scale a cluster without worrying about node-types
because every node is all node-types.
The extended functionality of this charm lends itself to the configuration of Elasticsearch clusters with non-uniform node-types.
# Deploy 3 units of each node-type
juju deploy elasticsearch es-master -n 3 --config config.yaml
juju deploy elasticsearch es-data -n 3 --config config.yaml
juju deploy elasticsearch es-ingest -n 3 --config config.yaml
juju deploy elasticsearch es-coordinator -n 3 --config config.yaml
# Make the relations between the components of the cluster
# and the master node
juju relate es-master:provide-master es-data:request-master
juju relate es-master:provide-master es-ingest:request-master
juju relate es-master:provide-master es-coordinator:request-master
This charm manages three files primarily, they are:
If you wish to make a customization to any of the aforementioned files, please
do so through the charm configuration options.
Only file based discovery is currently supported (pull requests welcome!).