I can't connect to elasticsearch using docker, what could be the reason?

Question

symfony

With these options, I can not create a connection to the database: localhost, 0.0.0.0, simpledocker2_elastics

In Http.php line 187:
<i>Couldn't connect to host, Elasticsearch down?</i>

ERROR     [elastica] Elastica Request Failure ["exception" => Elastica\Exception\Connection\HttpException { …},"request" => ["path" => "app","method" => "DELETE","data" => [],"query" => [],"contentType" => "application/json","connection" => ["config" => ["headers" => [],"curl" => []],"host" => "0.0.0.0","port" => 9200,"ssl" => false,"logger" => "fos_elastica.logger","compression" => false,"retryOnConflict" => 0,"enabled" => false]],"retry" => false]

config.yml

fos_elastica:
    clients:
        default: { host: 0.0.0.0, port: 9200}

Answer 1

Add links to php-fpm in docker-compose.yml and connect to:
$hosts = [
'elasticsearch'
];
$client = ClientBuilder::create()->setHosts($hosts)->build();

Answer 2

What is the second config? 0.0.0.0 - the host is specified only in the elastic server parameters so that it "listens" to all addresses, and not to any specific one. In the client, you must specify EITHER the IP address of the elastic (host or container), OR the name of the container (service) - if the elastic is running in the
localhost container and 127.0.0.1 for the container, this is, quite logically, the same container. In which NATURALLY elastic is not running. So it's pointless to do so. But there is an exception - when containers are launched without network isolation ( --net host)