ubuntu install elasticsearch

precondition##

This environment is operated on Ubuntu 18.04 by default.

We first need to configure the java environment, which requires Java8 or newer packages. Generally, you can check whether the Java version is compatible when you execute the following command:

sudo apt install default-jdk

Elasticsearch PGP Public Key##

We need to download and install the public key before installation, otherwise there is no way to install Elasticsearch using apt.

wget -qO - https://artifacts.elastic.co/GPG-KEY-elasticsearch | sudo apt-key add -

Install Elasticsearch

First add the source:

sudo apt-get install apt-transport-https
echo "deb https://artifacts.elastic.co/packages/6.x/apt stable main"| sudo tee -a /etc/apt/sources.list.d/elastic-6.x.list

Next, we can update the source to cut Es after all:

sudo apt-get update && sudo apt-get install elasticsearch

This is installed.

Elasticsearch command management##

We can use the systemd method for Elasticsearch management

`systemd`

Set boot up:

sudo systemctl daemon-reload
sudo systemctl enable elasticsearch

start up:

sudo systemctl start elasticsearch

shut down:

sudo systemctl stop elasticsearch

Check whether the installation is successful:

First we need to execute the command to start it (if it has already been started, then there is no need to execute the following start command):

sudo systemctl start elasticsearch

Then execute the following command:

curl -XGET '127.0.0.1:9200/?pretty'

If the returned data is as follows, the installation is successful:

{" name":"NLJug1O","cluster_name":"elasticsearch","cluster_uuid":"hVZpdHvgT9CeE1ywsNt16w","version":{"number":"6.2.4","build_hash":"ccec39f","build_date":"2018-04-12T20:37:28.497551Z","build_snapshot":false,"lucene_version":"7.2.1","minimum_wire_compatibility_version":"5.6.0","minimum_index_compatibility_version":"5.0.0"},"tagline":"You Know, for Search"}

Note: Elasticsearch needs to be started for a while. If you execute the above command immediately after startup, you may be prompted to refuse the connection, just try a few more times.

Configure Elasticsearch

Elasticsearch loads its configuration from the /etc/elasticsearch/elasticsearch.yml file by default.

RPM also has another system configuration file (/etc/sysconfig/elasticsearch), which allows you to set the following parameters:

Parameters	Explanation
JAVA_HOME	Set the custom Java path to be used
MAX_OPEN_FILES	Maximum number of open files, default 65536
MAX_LOCKED_MEMORY	Maximum lock memory size. If you use bootstrap.memory_lock option in elasticsearch.yml, please set unlimited
MAX_MAP_COUNT	The maximum value of the memory map area that a process may have. If you use mmapfs as the index storage type, make sure to set it to a higher value. Please check the linux kernel documentation for more information about max_map_count. This is set through sysctl before elasticsearch is started. The default is 262144
ES_PATH_CONF	Configuration file directory (need to include elasticsearch.yml and log4j2.properties files), the default path is: /etc/elasticsearch
ES_JAVA_OPTS	Any additional JVM system properties you may want to apply.
RESTART_ON_UPGRADE	The configuration package will be restarted when it is upgraded. The default is false. This means you manually restart the elasticsearch instance after installing the package. The reason for this is to ensure that, when updating in the cluster, the redistribution of shards is caused in the case of high-traffic networks and reducing the response time of your cluster.

Package directory layout##

Type	Description	Default Path	Settings
home	Elasticsearch home directory or $ES_HOME	/usr/share/elasticsearch
bin	binary script, including elasticsearch to start a node and elasticsearch-plugin to install plugins	/usr/share/elasticsearch/bin
conf	Configuration file, including elasticsearch.yml	/etc/elasticsearch	ES_PATH_CONF
conf	Environmental variables, including heap size, file descriptors.	/etc/default/elasticsearch
data	The location of the data file for each index/shard allocated on the node. Can accommodate multiple locations.	/var/lib/elasticsearch	path.data
logs	Log file location.	/var/log/elasticsearch	path.logs
plugins	Plugin file location. Each plugin will be contained in a subdirectory.	/usr/share/elasticsearch/plugins
repo	Shared file system repository location. Can accommodate multiple locations. The file system repository can be placed in any subdirectory of the specified directory.	Not configured	path.repo