php5.6-fpm curl 停止工作（无法解析主机）

突然间，我们的 Ubuntu php5.6-fpm 服务器停止处理 curl 请求。

这是我发现的：

从控制台运行时工作php test.php。

通过潮湿的工作console wget -qO- https://maps.google.com/maps/api/geocode/json?address=Brooklyn+NY+USA&key=AIzaSyBGgTVnShML1_WHJL0rOTEnt2XOrgVgnu4 | cat

使用 curl 从console ums-admin@svr1:/var/www/propertymonitor.ae/htdocs/v2$ curl https://maps.google.com/maps/api/geocode/json?address=Brooklyn+NY+USA&key=AIzaSyBGgTVnShML1_WHJL0rOTEnt2XOrgVgnu4

但是通过https://example.com/test.php上的 php-fpm 调用脚本它不起作用并抱怨 DNS 查找失败？！

重新启动 php5.6-fpm 并再次开始工作？！

下面的代码：

<?php
// create curl resource
$ch = curl_init();

// set url
curl_setopt($ch, CURLOPT_URL, "https://maps.google.com/maps/api/geocode/json?address=Brooklyn+NY+USA&key=AIzaSyBGgTVnShML1_WHJL0rOTEnt2XOrgVgnu4");

//return the transfer as a string
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

// $output contains the output string
$data = curl_exec($ch);

if ($data === false)
{
echo 'Curl error: ' . curl_error($ch);
} else {
echo 'Response: ' . $data;
}

// close curl resource to free up system resources
curl_close($ch);
?>

系统的其余部分检查：

cat /etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 8.8.8.8
nameserver 8.8.4.4
search example.com

并且没有丢包：

64 bytes from 8.8.8.8: icmp_seq=3150 ttl=46 time=129 ms
64 bytes from 8.8.8.8: icmp_seq=3151 ttl=46 time=124 ms
64 bytes from 8.8.8.8: icmp_seq=3152 ttl=46 time=124 ms
64 bytes from 8.8.8.8: icmp_seq=3153 ttl=46 time=124 ms
^C
--- 8.8.8.8 ping statistics ---
3153 packets transmitted, 3153 received, 0% packet loss, time 3154312ms
rtt min/avg/max/mdev = 114.975/124.705/139.692/2.004 ms