EC2 Metadata Mock Service

This provides a mock AWS EC2 instance metadata/user data service. The data served through the mock service is read from a json file.

Usage

NOTE: only tested on erlang R16B02

Download, install, compile, and create a release

git clone https://github.com/thbishop/ec2_metadata_mock-erlang.git
cd ec2_metadata_mock-erlang
./rebar create-node nodeid=ec2_metadata_mock
./rebar get-deps compile generate

You can then start it with:

env EC2_METADATA_FILE=$(pwd)/metadata.json rel/ec2_metadata_mock/bin/ec2_metadata_mock start

And stop it with:

rel/ec2_metadata_mock/bin/ec2_metadata_mock stop

Data

By default, the mock service will look for a metadata.json file in the current working directory.

The file should provide the desired data in a heirarchy.

For example:

{
  "meta-data": {
    "ami-id": "ami-77771920",
    "ami-launch-index": "1",
    ...
  },
  "user-data": "foo bar baz"
}

If desired, you can tell the service where to the find the json file with the EC2_METADATA_FILE environment variable.

env EC2_METADATA_FILE=/var/tmp/foo.json rel/ec2_metadata_mock/bin/ec2_metadata_mock start

Address/Port Binding

By default, the service will bind to all addresses on port 8080.

You can override the bind address and port using environment variables.

To bind to a different port, you can do:

env EC2_METADATA_PORT=9000 rel/ec2_metadata_mock/bin/ec2_metadata_mock start

And to a different address:

env EC2_METADATA_ADDRESS=192.168.1.10 rel/ec2_metadata_mock/bin/ec2_metadata_mock start

If you want to truly mimic the EC2 metadata service, you'll want to listen on 169.254.169.254.

To do so on OSX, you can add another address with:

sudo ifconfig lo0 alias 169.254.169.254

If you want to remove the address, you can do so with:

sudo ifconfig lo0 -alias 169.254.169.254

On linux, you can do:

sudo ifconfig eth0:1 169.254.169.254

And to remove it:

sudo ifconfig eth0:1 down

And then start and bind to the new address:

sudo env EC2_METADATA_PORT=80 EC2_METADATA_IP_ADDRESS=169.254.169.254 \
  rel/ec2_metadata_mock/bin/ec2_metadata_mock start

Contribute

• Fork the project
• Make your feature addition or bug fix (with tests and docs) in a topic branch
• Send a pull request and I'll get it integrated

License

See LICENSE file for details