host.id is set to empty value in containerized setups

[mx-psi]

Description

The resource.WithHostID option sets the host.id resource attribute to the empty string on (certain) containerized setups. The attribute should be set in accordance to the specification which states that host.id should be a:

Unique host ID. For Cloud, this must be the instance_id assigned by the cloud provider. For non-containerized systems, this should be the machine-id. See the table below for the sources to use to determine the machine-id based on operating system.

An empty string is not a unique host ID.

Environment

• OS: Ubuntu 22.04.2, likely irrelevant
• Architecture: x86_64, likely irrelevant
• Go Version: go1.19, likely irrelevant
• opentelemetry-go version: Tested with v1.16.0

Steps To Reproduce

Run the binary resulting from the following program:

package main

import (
	"context"
	"fmt"

	"go.opentelemetry.io/otel/sdk/resource"
)

func main() {
	res, err := resource.New(context.Background(),
		resource.WithHostID(),
	)

	if err != nil {
		panic(err)
	}

	fmt.Println(res)
}

On any of the following images:

• alpine
• ubuntu
• centos
• a FROM scratch image (see [processor/resourcedetection] system detector sets host.id to an empty value on containerized setups opentelemetry-collector-contrib#24230)

The resulting output is:

host.id=

Expected behavior

The host.id resource attribute is either not set or set to a value that is specification compliant.

---

cc @mwear. I have not tried to reproduce this on opentelemetry-js but it's likely the issue occurs there as well.

[mwear]

I'll fix this.

[mwear]

I opened #4317. It is a fix for this problem, but may or may not be the fix we're looking for. Take a look at the PR description and we can decide what the right thing to do is.

[pellared]

According to the description it indeed fixes the bug

The host.id resource attribute is either not set or set to a value that is specification compliant.

However, I think it would be good to open another issue (enhancement) to provide a more meaningful value.