Nginx active check

conf.ngx

upstream zen_zen-front_production_splitter {
    keepalive 2;
    server [2a02:06b8:0c00:3b10:0000:1452:7fb3:1e24]:80 max_fails=0 fail_timeout=60 weight=1;
    server [2a02:06b8:0c08:f427:0000:1452:005d:5634]:80 max_fails=0 fail_timeout=60 weight=1;
    check interval=5000 rise=2 fall=3 timeout=2000 default_down=false type=http;
    check_http_send "GET /ok.html HTTP/1.0\r\n\r\n";
    check_http_expect_alive http_2xx;
}

match statusok {
    # Used for /test.php health check
    status 200;
    header Content-Type = text/html;
    body ~ "Server[0-9]+ is alive";
}