我们开始实例，并访问用户数据，我们的地方。但是，有谁知道这个操作的内部（从亚马逊的一侧）？当我们在传递用户数据，在什么点是传送到虚拟机的数据（这是一个Xen的功能），并在那里被它存储在哪里？

We are starting instances, and accessing the user-data we place. But does anybody understand the internals of this operation (from Amazon's side)? When we pass in the user-data, at what point is that data transmitted to the VM (is this a Xen feature) and where is it stored?

我首先想到的，它被设置为USER_DATA的环境变量，但我们也可以把它作为一个文件。哪里该文件存​​储在哪里？它是通用的所有实例或取决于AMI？

I first thought, it was set as the USER_DATA env var, but we can also pass it as a file. Where is that file stored? Is it generic to all instances or varies depending on AMI?

这是不是本身，只是想知道亚马逊是如何做到这一点的一个问题。

This is not a problem per se, just wanted to know how Amazon does this.

用户数据截图： http://d.pr/GZlY

推荐答案

用户数据可与在此URL一个简单的HTTP请求的实例：

The user-data is available to the instance with a simple HTTP request at this URL:

http://169.254.169.254/latest/user-data

亚马逊EC2并没有把这个用户数据的情况下直接，但许多的AMI有code，指示的情况下自动下载并处理用户数据。

Amazon EC2 does not put this user-data on the instance directly, though many AMIs have code that instructs the instance to download and process the user-data automatically.

另请参阅：

的http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-metadata.html

HTTP：//docs.aws.amazon .COM / AWSEC2 /最新/ UserGuide /用户data.html