Installing Elasticsearch under Linux is the most detailed tutorial in history~

Posted by cgchris99 on Fri, 21 Jan 2022 23:47:27 +0100

1 Preface

Elasticsearch is a popular search engine in Java. The traditional database search uses the like 'keyword%'. When there is too much content, the performance will be greatly reduced, so elasticsearch appears.

Next, record the installation process of Elasticsearch under Linux.

2. Install Elasticsearch under Linux

2.1 download and unzip the installation package

  • Official website download address: https://www.elastic.co/cn/downloads/elasticsearch

    Select the appropriate version to download, and then upload it to Linux

    You can also directly execute the following commands on the Linux command line to download (the download is slow):
    wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-7.13.2-linux-x86_64.tar.gz

  • Execute the decompression command:
    tar -zxvf elasticsearch-7.13.2-linux-x86_64.tar.gz -C /usr/local

2.2 solving the problem of es strongly relying on jdk

Because es and jdk are strongly dependent, when we include our own jdk in the ElasticSearch package of the new version, but after we have installed the jdk in Linux, we will find that when we start es, we first look for the installed jdk in Linux. At this time, if the jdk versions are inconsistent, the jdk will not run normally. The error is as follows:

Note: if the jdk is not configured for the Linux service, the default jdk under the es directory will be used directly, but no error will be reported

warning: usage of JAVA_HOME is deprecated, use ES_JAVA_HOME
Future versions of Elasticsearch will require Java 11; your Java version from [/usr/local/jdk1.8.0_291/jre] does not meet this requirement. Consider switching to a distribution of Elasticsearch with a bundled JDK. If you are already using a distribution with a bundled JDK, ensure the JAVA_HOME environment variable is not set.

terms of settlement:

  • Enter the bin directory
    cd /usr/local/elasticsearch-7.13.2/bin

  • Modify elasticsearch configuration
    vim ./elasticsearch

    ############## Add configuration resolution jdk Version problem ##############
# Modify the jdk to the configuration directory of the jdk in es
export JAVA_HOME=/usr/local/elasticsearch-7.13.2/jdk
export PATH=$JAVA_HOME/bin:$PATH

if [ -x "$JAVA_HOME/bin/java" ]; then
        JAVA="/usr/local/elasticsearch-7.13.2/jdk/bin/java"
else
        JAVA=`which java`
fi

2.3 solve the problem of insufficient memory

Since the jvm space allocated by elasticsearch is 2g by default, it is unnecessary to modify the jvm space if the Linux server is originally configured with a high configuration.

error:
OpenJDK 64-Bit Server VM warning: INFO: os::commit_memory(0x00000000c6a00000, 962592768, 0) failed; error='Not enough space' (errno=12)
        at org.elasticsearch.tools.launchers.JvmOption.flagsFinal(JvmOption.java:119)
        at org.elasticsearch.tools.launchers.JvmOption.findFinalOptions(JvmOption.java:81)
        at org.elasticsearch.tools.launchers.JvmErgonomics.choose(JvmErgonomics.java:38)
        at org.elasticsearch.tools.launchers.JvmOptionsParser.jvmOptions(JvmOptionsParser.java:13

Enter the config folder to start configuration and edit the JVM options:
vim /usr/local/elasticsearch-7.13.2/config/jvm.options

The default configuration is as follows:
-Xms2g
-Xmx2g
 The default configuration takes up too much memory. Turn it down:
-Xms256m
-Xmx256m

2.4 create a dedicated user to start ES

root cannot directly start Elasticsearch, so you need to create a special user to start ES

java.lang.RuntimeException: can not run elasticsearch as root
        at org.elasticsearch.bootstrap.Bootstrap.initializeNatives(Bootstrap.java:101)
        at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:168)
        at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:397)
        at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:159)
        at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:150)
        at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:75)
        at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:116)
        at org.elasticsearch.cli.Command.main(Command.java:79)
        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:115)
        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:81)

  • Create user
    useradd user-es

  • Create group:
    chown user-es:user-es -R /usr/local/elasticsearch-7.13.2

  • Switch to user es user
    su user-es

  • Enter the bin directory
    cd /usr/local/elasticsearch-7.13.2/bin

  • Start elasticsearch
    ./elasticsearch

If the following error message appears (the maximum number of files is too small, the thread is too small, and the memory is too low):

2.5 modify ES core configuration information

  • Execute the command to modify elasticsearch YML file content
    vim /usr/local/elasticsearch-7.13.2/config/elasticsearch.yml

  • Modify data and log directories
    You don't need to modify it here. If you don't modify it, it will be placed in the elasticsearch root directory by default

    # Data directory location
path.data: /home/New user name/elasticsearch/data 
# Log directory location
path.logs: /home/New user name/elasticsearch/logs

  • Modify the bound ip to allow remote access

    #Only local access is allowed by default. After it is modified to 0.0.0.0, it can be accessed remotely
# Bind to 0.0.0.0 and allow any ip to access
network.host: 0.0.0.0

  • Initialization node name

    cluster.name: elasticsearch 
node.name: es-node0
cluster.initial_master_nodes: ["es-node0"]

  • Modify port number (not required)

    http.port: 19200

2.6 vm.max_map_count [65530] is too low

The above steps still fail to start successfully. Continue to solve the problem:

ERROR: [1] bootstrap checks failed. You must address the points described in the following [1] lines before starting Elasticsearch.
bootstrap check failure [1] of [1]: max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]

elasticsearch user has too little memory permission and needs at least 262144. Solution:
In / etc / sysctl The conf file can be permanently modified by adding the following contents at the end

  • Switch to root
    Execute the command: su root

  • Execute command
    vim /etc/sysctl.conf

  • Add the following
    vm.max_map_count=262144

  • Save exit, refresh configuration file
    sysctl -p

  • Switch the user es user and continue to start
    su user-es

  • Start es service
    /usr/local/elasticsearch-7.13.2/bin/elasticsearch

After successful startup, you can http://127.0.0.1:19200/ Access. If the following contents appear, the ES installation is successful:

{
	"name": "es-node0",
	"cluster_name": "elasticsearch",
	"cluster_uuid": "SRwJX4sYQ8el4N5wj4tOmA",
	"version": {
	"number": "7.13.2",
	"build_flavor": "default",
	"build_type": "tar",
	"build_hash": "4d960a0733be83dd2543ca018aa4ddc42e956800",
	"build_date": "2021-06-10T21:01:55.251515791Z",
	"build_snapshot": false,
	"lucene_version": "8.8.2",
	"minimum_wire_compatibility_version": "6.8.0",
	"minimum_index_compatibility_version": "6.0.0-beta1"
	},
	"tagline": "You Know, for Search"
}

2.7 possible max file descriptors [4096] problems

[1]: max file descriptors [4096] for elasticsearch process is too low, increase to at least [65535]

Switch to root and execute the command:
vi /etc/security/limits.conf

Add the following:

* soft nofile 65536
* hard nofile 131072
* soft nproc 2048
* hard nproc 4096

Then restart linux

2.8 start and stop of ES service

  • The foreground runs, and Ctrl + C terminates the program
    ./elasticsearch

  • Background operation
    ./elasticsearch -d
    Start complete when started appears

  • Shut down ES service
    kill pid

    explain:
    Elasticsearch port 9300, 9200, where:
    9300 is the tcp communication port, which is used for communication between cluster ES nodes, and 9200 is the RESTful interface of http protocol

Well, the stand-alone Elasticsearch service has finally been installed. It's still a little troublesome~

3. Install the elasticsearch head plug-in

Easticsearch only provides various restful APIs on the back end, so how can we intuitively see its information?

Elasticsearch head is a client tool for elasticsearch, which is used to display data.

Elastic search head is written in JavaScript language and can be deployed using npm
npm is the package manager under Nodejs.

3.1 installing node environment

If the Linux service has installed the node environment, you can skip this step. If there is no node environment, you can refer to another blog post: Installing node environment under Linux

When the npm environment is ready, install elastic search head

3.2 installing elasticsearch head

3.2.1 download elasticsearch head installation package

Download address: https://github.com/mobz/elasticsearch-head

3.2.2 unzip the zip package

Execute command:
unzip elasticsearch-head-5.0.0.zip

Move the installation package to / usr/local:
mv elasticsearch-head-5.0.0 /usr/local/

3.2.3 npm install

  • Enter the installation directory
    cd /usr/local/elasticsearch-head-5.0.0

  • Execute command installation
    npm install
    Note: if the execution fails, you can install cnpm. Before using cnpm, you need to install cnpm through
    npm install -g cnpm --registry=https://registry.npm.taobao.org This command installs

  • Display all usage help information
    npm -l

Under the root directory of each project, there is usually a package JSON file, which defines various modules required by the project and the configuration information of the project (such as metadata such as name, version, license, etc.)

The npm install command automatically downloads the required modules according to the configuration file, that is, the running and development environment required for the configuration project.

3.2.4 start elasticsearch head service

  • Start service
    npm run start or NPM run script start

  • It can be started in the background
    nohup npm run-script start &

The following figure shows that the elasticsearch head service is started successfully:

3.2.5 accessing elasticsearch head service

Then visit: http://localhost:9100/

Elasticsearch head service accessed successfully:

3.2.6 accessing elasticsearch using Head plug-in

Failed to access. To allow cross domain, you need to modify elasticsearch YML file, add the following:

http.cors.enabled: true
http.cors.allow-origin: "*"

The following interface appears, indicating that the access is successful:

Well, this tutorial is here first. Welcome old fellow commentary.

Reference links: https://www.cnblogs.com/jhtian/p/12664890.html

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If there is any problem, you are welcome to discuss it together. If there is any problem with the code, you are welcome to correct it!

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Topics: Linux ElasticSearch

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