Example of config.php with elasticsearch config:
<?php
return [
// .... other configs
'install' => [
'date' => 'Tue, 11 Aug 2020 20:39:54 +0000'
],
'system' => [
'default' => [
'catalog' => [
'search' => [
'engine' => 'elasticsearch7',
'elasticsearch5_server_hostname' => 'localhost',
'elasticsearch7_server_port' => '9200'
]
]
]
]
];