PHP Parsing Amazon EC2 instance 'launchTime'

FINAL ANSWER:

Okay, after checking out this thread, I've decided on this approach as the only one that seems to return an accurate measure:

$dt = DateTime::createFromFormat('Y-m-dTH:i:s.uZ', $date);
$now = new DateTime();
echo ($now->getTimestamp() - $dt->getTimestamp())."n";

ATTEMPTS:

In PHP 5.3 using classes (no 'U' format):

$dt = DateTime::createFromFormat('Y-m-dTH:i:s.uZ', $arr['launchTime']);
echo (new DateTime())->format('U');

In PHP 5.3 using procedural calls (also works like final solution):

$dt = date_create_from_format('Y-m-dTH:i:s.uZ', $arr['launchTime']);
$now = date_create();
echo ($now->getTimestamp() - $dt->getTimestamp());

In any version using strtotime (return wrong time):

date_default_timezone_set('UTC');
echo time() - strtotime($arr['launchTime']);

After a lot of "scratching my head", I finally figured it out.

First of all you one need to figure out the current user who is executing the php. One can either check out php.info file or use

$processUser = posix_getpwuid(posix_geteuid());
print $processUser['name'];

This will give you the user who is executing the code. In my case it was apache rather than www-data (I shouldn't have assumed so in first place).

After that you will need to edit the sudoers file (etc/sudoers)

Add the lines over there.

apache ALL=NOPASSWD:/var/www/myfile.py
apache ALL=NOPASSWD:/usr/bin/pythondestination

or you can simply add

apache ALL=(ALL)        NOPASSWD:ALL

(You probably should just specify the path).

Then execute the script through php.

Anything that is not stored on an EBS volume that is mounted to the instance will be lost.

For example, if you mount your EBS volume at /mystuff, then anything not in /mystuff will be lost. If you don't mount an ebs volume and save stuff on it, then I believe everything will be lost.

You can create an AMI from your current machine state, which will contain everything in your ephemeral storage. Then, when you launch a new instance based on that AMI it will contain everything as it is now.

Update: to clarify based on comments by mattgmg1990 and glenn bech:

Note that there is a difference between "stop" and "terminate". If you "stop" an instance that is backed by EBS then the information on the root volume will still be in the same state when you "start" the machine again. According to the documentation, "By default, the root device volume and the other Amazon EBS volumes attached when you launch an Amazon EBS-backed instance are automatically deleted when the instance terminates" but you can modify that via configuration.