PHP on Linux should use /dev/urandom when getrandom is not available
There is a bug in the PHP 7 version shipped with alpine 3.5 which prevents docker images from working on older kernels. This bug is already fixed in the PHP 7.0.17 version.
See: https://bugs.php.net/bug.php?id=74105
Please provide a new package for alpine 3.5.
Thanks
(from redmine: issue id 7264, created on 2017-05-03, closed on 2017-05-03)