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https://github.com/bpholt/fake-ec2-metadata-service
Small app which simulates some of the EC2 Metadata Service
https://github.com/bpholt/fake-ec2-metadata-service
hacktoberfest
Last synced: 11 days ago
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Small app which simulates some of the EC2 Metadata Service
- Host: GitHub
- URL: https://github.com/bpholt/fake-ec2-metadata-service
- Owner: bpholt
- License: mit
- Created: 2015-09-02T00:29:45.000Z (about 9 years ago)
- Default Branch: main
- Last Pushed: 2024-10-24T14:29:10.000Z (14 days ago)
- Last Synced: 2024-10-25T18:18:31.999Z (12 days ago)
- Topics: hacktoberfest
- Language: Scala
- Homepage: https://hub.docker.com/r/bpholt/fake-ec2-metadata-service/
- Size: 466 KB
- Stars: 18
- Watchers: 4
- Forks: 7
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
- Codeowners: .github/CODEOWNERS
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README
# Fake EC2 Metadata Service
[](https://microbadger.com/images/bpholt/fake-ec2-metadata-service)
[]()
You’re developing an app that will run in a VM locally but relies on the [EC2 Metadata Service](http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-metadata.html) for some part of its behavior when running in Amazon’s cloud. How do you run the same thing locally?
Enter the Fake EC2 Metadata Service, a simple http4s app that exposes some of the functionality running on http://169.254.169.254.
## Override IMDS Endpoint Url
Set the `AWS_EC2_METADATA_SERVICE_ENDPOINT` environment variable in the process that you'd like to use the Fake EC2 Metadata Service.
If you do this, you can run this on whatever port you want and ignore all the following setup instructions!
## Setup on Linux
Create a loopback interface bound to 169.254.169.254 (this probably needs to be run with root privileges):
```
ifconfig lo:0 169.254.169.254 netmask 255.255.255.255 up
```
Now run the app:
```
docker-compose up
```
## Setup on Mac
[Docker for Mac](https://docker.com/mac) [doesn’t support the same type of networking features that it does on Linux](https://docs.docker.com/docker-for-mac/networking/#/there-is-no-docker0-bridge-on-macos), so we need a different process.
On El Capitan and Sierra, we can redirect outgoing traffic intended for 169.254.169.254 back to the port forwarding set up by Docker.
```
+---------------------------------------------+ +-------------------------------------+
|HTTP Client | |pf |
| GET /latest/meta-data/local-ipv4 HTTP/1.1 +----------> Reroute outgoing traffic from |
| Host: 169.254.169.254 | | 169.254.169.254:80 to 127.0.0.1:80 |
| | +-------------------------+-----------+
+---------------------------------------------+ |
|
|
+---------------------------------------------+ +-------------------------v-------+
|Docker port forwarding | |pf |
| Forward traffic from 127.0.0.1:8169 to <----------+ Redirect traffic from |
| published Container Port | | 127.0.0.1:80 to 127.0.0.1:8169 |
| | +---------------------------------+
+---------------------+-----------------------+
|
|
+--------------v---------------+
|Fake EC2 Metadata Service |
| 200 OK |
| … |
| |
+------------------------------+
```
Create a file in `/etc/pf.anchors/fake-ec2-metadata-service` containing the following:
```
Packets = "proto tcp from any to 169.254.169.254 port 80"
rdr pass log on lo0 $Packets -> 127.0.0.1 port 8169
pass out log route-to lo0 inet $Packets keep state
```
Then, at the very bottom of `/etc/pf.conf`, load the `pf` rules:
```
load anchor "fake-ec2-metadata-service" from "/etc/pf.anchors/fake-ec2-metadata-service"
```
Immediately after the first Apple `anchor`, include the `fake-ec2-metadata-service` filter rules:
```
anchor "fake-ec2-metadata-service"
```
Immediately after the first Apple `rdr-anchor`, include the `fake-ec2-metadata-service` redirection rules:
```
rdr-anchor "fake-ec2-metadata-service"
```
The entire file should look something like this:
```
scrub-anchor "com.apple/*"
nat-anchor "com.apple/*"
rdr-anchor "com.apple/*"
rdr-anchor "fake-ec2-metadata-service"
dummynet-anchor "com.apple/*"
anchor "com.apple/*"
anchor "fake-ec2-metadata-service"
load anchor "com.apple" from "/etc/pf.anchors/com.apple"
load anchor "fake-ec2-metadata-service" from "/etc/pf.anchors/fake-ec2-metadata-service"
```
Load and enable the `pf` rules by executing
```
sudo pfctl -F all -f /etc/pf.conf
sudo pfctl -E
```
Run the container by executing
```
docker-compose up
```
## Example Requests
```
curl http://169.254.169.254/latest/meta-data/local-ipv4
curl http://169.254.169.254/latest/meta-data/local-hostname
curl http://169.254.169.254/latest/meta-data/iam/security-credentials/
curl http://169.254.169.254/latest/meta-data/iam/security-credentials/default
```