Server: EC2ws response header is missing

[mumoshu]

Hi, thanks for sharing this project :)

When I run curl --dump-header 169.254.169.254 on "actual" EC2 instances, I get:

$ curl --dump-header - http://169.254.169.254
HTTP/1.0 200 OK
Content-Type: text/plain
Accept-Ranges: bytes
ETag: "83579665"
Last-Modified: Thu, 19 May 2016 08:21:00 GMT
Content-Length: 153
Connection: close
Date: Fri, 27 May 2016 06:36:38 GMT
Server: EC2ws

*snip*

which includes the Server: EC2ws header.
Running the same curl command against aws-mock-metadata doesn't return it.

It may be a problem when you tried to use aws-mock-metadata to test applications that expect metadata service to return that header.
An example of such application is fluentd-plugin-google-cloud which relies on it to determine where it is running on(EC2 or GCE).

https://github.com/GoogleCloudPlatform/fluent-plugin-google-cloud/blob/b1db6ef/lib/fluent/plugin/out_google_cloud.rb#L507