microsoft/azureimds

Azure Instance Metadata Samples

Azure Instance Metadata Samples

This repo contains samples in various languages to call into Azure Instance Metadata Service from within the VM in Azure. Please refer to LICENSE terms for use.

More details on Azure Instance Metadata service can be found here https://aka.ms/azureimds

azureimds's Issues

IMDSSample.sh is broken

sudo apt-get jq ---> "sudo apt-get install -y jq" worked for me.

IMDS Service returns unexpected results on PublicIpAddress when used with a VMSS

IMDS Service returns blank PublicIpAddress when used with a Virtual Machine Scale Set (VMSS) with a backend pool and public IP addresses associated with the VMSS VMs.

Expected Behavior

The IMDS service would provide the Public IP Address that has been associated with the VM when the VM is part of a loadbalancer backend pool and has an associated public IP address.

Using the following curl command to the IMDS endpoint:
curl -s -H Metadata:true --noproxy "*" http://169.254.169.254/metadata/instance/network/interface/0/ipv4/ipAddress?api-version=2021-12-13

Resulting output:
[{"privateIpAddress":"XX.X.X.X","publicIpAddress":"XXX.XXX.XXX.XXX"}]

Current Behavior

When a VMSS has a public facing load balancer that has the instance part of its backend pool and each instance also has a public IP address associated to it, the IMDS does not return a public IP address to the instance via IMDS.

Using the following curl command to the IMDS endpoint:
curl -s -H Metadata:true --noproxy "*" http://169.254.169.254/metadata/instance/network/interface/0/ipv4/ipAddress?api-version=2021-12-13

Resulting output:
[{"privateIpAddress":"XX.X.X.X","publicIpAddress":""}]

Steps to Reproduce

1. Provision a VMSS of linux VMs using a Public Load Balancer and each VM associated with that load balancer.
2. Provision an additional VMSS of linux VMs using only Public IP addresses and NO load balancer.
3. Provision a final VMSS of linux VMs using both a Public IPs for each VM and a public load balancer associated to each VM in the VMSS.
4. Curl metadata service with above curl on a VM within each VMSS to observe the results.

This repo is missing important files

There are important files that Microsoft projects should all have that are not present in this repository. A pull request has been opened to add the missing file(s). When the pr is merged this issue will be closed automatically.

Microsoft teams can learn more about this effort and share feedback within the open source guidance available internally.

Merge this pull request

Update IMDSSample.py to use requests

Use requests (default with recent Python 3 versions) to simplify the existing example,
Also, increment api-version to 2017-08-01 so it supports tags.
e.g.

#!/usr/bin/env python3
import json
import requests

endpoint = "http://169.254.169.254/metadata/instance/compute?api-version=2017-08-01"
headers={'Metadata': 'True'}
json_obj = requests.get(endpoint, headers=headers).json()

print(json.dumps(json_obj, sort_keys=True, indent=4, separators=(',', ': ')))