Elasticsearch Containers: Nexcess Cloud & the API

Elasticsearch Containers – Using the API

What are Elasticsearch Containers?

Elasticsearch is a fast, scalable, open source search engine for large amounts of structured and unstructured data. Elasticsearch can be used for a variety of applications, and it is required for recent versions of Magento. 

Elasticsearch containers are external instances of Elasticsearch within the Nexcess cloudhost network that are running in docker containers with minimal overhead. When they are enabled in the Nexcess portal for your application, an endpoint and port are provided that will be needed in order to utilize the API commands described below. Here is an example endpoint and port:

This tutorial will cover some basics of how to use the Elasticsearch API with Nexcess Managed Apps cloud containers. This covers how to connect and check uptime, verify resource usage, and change some settings for the Elasticsearch container. 

How to Connect to the Elasticsearch Container

Nexcess Elasticsearch containers are not accessible from outside the internal network, and so it’s necessary to log in via SSH to the cloudhost account to connect to it directly. Next, check for a simple response using the following curl command, replacing with actual endpoint and port found in portal under Plans > Plan Dashboard > Containers:

curl -X GET $endpoint:$port

Example:

curl -X GET cg-8977-elasticsearch.nl-west-1.nxcli.net:63511
{
"name" : "8487575a9cfc",
"cluster_name" : "docker-cluster",
"cluster_uuid" : "Jzkz1EWFTPeuQFq1gQEf5w",
"version" : {
"number" : "7.9.3",
"build_flavor" : "default",
"build_type" : "docker",
"build_hash" : "c4138e51121ef06a6404866cddc601906fe5c868",
"build_date" : "2020-10-16T10:36:16.141335Z",
"build_snapshot" : false,
"lucene_version" : "8.6.2",
"minimum_wire_compatibility_version" : "6.8.0",
"minimum_index_compatibility_version" : "6.0.0-beta1"
},
"tagline" : "You Know, for Search"
}

Container Diagnostics

Heap size: current memory usage and percent of total:

$ curl -s 'cg-9871-elasticsearch.au-south-1.nxcli.net:4250/_cat/nodes?v&h=hc,hp'

Response will look something like the following. Here 624.9mb are in use by the container, or 62% of the total available (1G):

    hc hp
624.9mb 62

Uptime

This is pretty self-explanatory; the response should give the total uptime of the container:

curl -s 'cg-8997-elasticsearch.nl-west-1.nxcli.net:63511/_cat/nodes?v&h=uptime'

 10.3d

Elasticsearch “Yellow” Status

If the health statuses of the container indices are reporting as yellow, or logs are showing the error ‘the shard cannot be allocated to the same node on which a copy of the shard already exists’, the yellow status will not actually cause any issues because the container is running as a single node and so there are no replicas. The number_of_replicas setting is set to 1 by default, but it can be changed to 0 using the Elasticsearch API. Example of yellow status:

$ curl -s 'cg-8997-elasticsearch.nl-west-1.nxcli.net:63511/_cat/indices?v'
health status index     uuid                   pri rep docs.count docs.deleted store.size pri.store.size
yellow open test_stg_product_1     rXnBOT2QQuKklj305xNVGw