====== Elasticsearch ======

==== Prerequisites ====

=== Install Java ===

- Check if Java already installerd:

<code bash>
java -version
</code>

- Install OpenJDK

<code bash>
sudo apt install default-jre
</code>

- Verify installed JDK version

<code bash>
javac -version
</code>

- Setting the JAVA_HOME Environment Variable

<code bash>
sudo update-alternatives --config java
</code>

<code bash>
sudo vi /etc/environment
</code>

<code bash /etc/environment>
...
JAVA_HOME="/usr/lib/jvm/java-11-openjdk-amd64"
ES_JAVA_HOME="/usr/lib/jvm/java-11-openjdk-amd64"
</code>

<code bash>
source /etc/environment
</code>

<code bash>
echo $JAVA_HOME
</code>

=== Install wget ===

<code bash>
sudo apt install wget
</code>


==== 1. Install Elasticsearch ====

<code bash>
curl -fsSL https://artifacts.elastic.co/GPG-KEY-elasticsearch |sudo gpg --dearmor -o /usr/share/keyrings/elastic.gpg
</code>

<code bash>
echo "deb [signed-by=/usr/share/keyrings/elastic.gpg] https://artifacts.elastic.co/packages/7.x/apt stable main" | sudo tee -a /etc/apt/sources.list.d/elastic-7.x.list
</code>

<code bash>
sudo apt update
</code>

<code bash>
sudo apt install elasticsearch
</code>

<code bash>
sudo vi /etc/elasticsearch/elasticsearch.yml
</code>

<code bash /etc/elasticsearch/elasticsearch.yml>
...
# ---------------------------------- Network -----------------------------------
#
# By default Elasticsearch is only accessible on localhost. Set a different
# address here to expose this node on the network:
#
network.host: localhost
...
</code>

<code bash>
sudo systemctl start elasticsearch
</code>

<code bash>
sudo systemctl enable elasticsearch
</code>

<code bash>
curl -X GET "localhost:9200"
</code>

<code bash Output>
{
  "name" : "Elasticsearch",
  "cluster_name" : "elasticsearch",
  "cluster_uuid" : "n8Qu5CjWSmyIXBzRXK-j4A",
  "version" : {
    "number" : "7.17.2",
    "build_flavor" : "default",
    "build_type" : "deb",
    "build_hash" : "de7261de50d90919ae53b0eff9413fd7e5307301",
    "build_date" : "2022-03-28T15:12:21.446567561Z",
    "build_snapshot" : false,
    "lucene_version" : "8.11.1",
    "minimum_wire_compatibility_version" : "6.8.0",
    "minimum_index_compatibility_version" : "6.0.0-beta1"
  },
  "tagline" : "You Know, for Search"
}
</code>
==== 2. Install Kibana ====

==== 3. Install Logstash ====