Magento 2.4 Installation: In SearchConfig.php line 81: Could not validate a connection to Elasticsearch. No alive nodes found in your cluster

I encountered this problem which is really tiring when installing a new Magento 2.4.

I think you have already found the solution but I wanted to share the solution for others.

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^{In SearchConfig.php line 81: Could not validate a connection to Elasticsearch. No alive nodes found in your cluster}

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This error means that either you don't have Elasticsearch installed in your system or the host configuration which is not correct.

1. check if Elasticsearch is installed :

   with example :

   sudo systemctl status elasticsearch
   
   //or
   
   curl -X GET 'http://localhost:9200'
   
   //or
   
   curl -X GET 'http://yourdomaine:9200'
   

2. if you find that Elasticsearch is installed, you go directly to step 4, otherwise you go to step 3 then 4

3. Elasticsearch installation : Reference

   3.1 We must have OpenJDK to make work Elasticsearch

   sudo apt install openjdk-11-jdk -y
   

   3.2 import the Elasticsearch public GPG key

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

   3.3 add the Elasticsearch source to the sources.list.d directory, where apt will search for new sources

   sudo echo "deb https://artifacts.elastic.co/packages/7.x/apt stable main" | sudo tee -a /etc/apt/sources.list.d/elastic-7.x.list
   

   3.4 update the packages to read the Elastic source

   sudo apt update
   

   3.5 install Elasticsearch

   sudo apt install elasticsearch -y
   

   3.6 we configure Elasticsearch host

   sudo nano /etc/elasticsearch/elasticsearch.yml
   

   uncomment and replace #network.host: 192.168.0.1 with network.host: localhost

    # ---------------------------------- Network -----------------------------------
    #
    # Set the bind address to a specific IP (IPv4 or IPv6):
    #
    #network.host: 192.168.0.1 //<- **** uncomment this line then replace it with : network.host: localhost
    #
    # Set a custom port for HTTP:
    #
    #http.port: 9200
    #
    # For more information, consult the network module documentation.
   

   3.7 We start Elasticsearch

    sudo systemctl start elasticsearch
    sudo systemctl enable elasticsearch
   

   3.8 We check the status

    sudo systemctl status elasticsearch
   
    //result : 
   
    //systemd[1]: Starting Elasticsearch...
   

   3.9 Working Elastic

    curl -X GET 'localhost:9200' 
   
    //Result something like : 
    {
      "name" : "wbfdfrbz",
      "cluster_name" : "elasticsearch",
      "cluster_uuid" : "_MpzR9k23l-Vy5vzlSQW",
      "version" : {
        "number" : "7.9.0",
        "build_flavor" : "default",
        "build_type" : "deb",
        "build_hash" : "a179a2a7fwq032d6g9361301700902wff217",
        "build_date" : "2020-08-11T21:36:48.204330Z",
        "build_snapshot" : false,
        "lucene_version" : "8.6.0",
        "minimum_wire_compatibility_version" : "6.8.0",
        "minimum_index_compatibility_version" : "6.0.0-beta1"
      },
     "tagline" : "You Know, for Search"
    }
   

 

4. Magento command installation

   In step 3.6, we set the HOST value with : localhost (network.host: localhost) so we will set the same thing for --elasticsearch-host='localhost' and --elasticsearch-port=9200, we have keep the default port 9200 (#http.port: 9200).

   So an example for the Magento CLI installation :

   php bin/magento setup:install --base-url="http://yourdomaine.com/" --base-url-secure="http://yourdomaine.com/" --backend-frontname="admin" --session-save="files" --db-host="localhost" --db-name="your-db-name" --db-user="your-db-user" --db-password="your-db-password" --admin-firstname="Amir" --admin-lastname="Admin" --admin-email="[email protected]" --admin-user="amir" --admin-password="Admin123" --language=fr_FR --currency=EUR --timezone=Europe/Paris --use-rewrites=1 --search-engine=elasticsearch7 --elasticsearch-host="localhost" --elasticsearch-port=9200
   

Enjoy !

You can refer to how to install the latest magento 2.4 here https://vi-magento.com/cai-dat-magento-2-4-voi-nginx-apache-php-7-3-va-mysql-thong-qua-composer-tren-ubuntu