darwin/arm64 (Apple Silicon M1) support

[jamesrwhite]

Hi,

I wanted to ask if there any plans to build binaries for darwin/arm64 to support running node_exporter natively on MacOS machines running M1 processors?

This would require updating to Go 1.16 also I believe as that's when support for that arch was added.

We currently have the following version of node_exporter running:

node_exporter, version 1.1.1 (branch: , revision: )
  build user:       Homebrew
  build date:
  go version:       go1.15.7
  platform:         darwin/amd64

We are running it under Rosetta on MacOS 11.0.1 but there are known issues with earlier versions of Rosetta and Go (golang/go#42700) that I believe we are also seeing. Supposedly they are fixed in later versions of Rosetta but I'd prefer if we could run it natively regardless.

I'm not that familiar with the code base but I'm happy to help with implementing/testing if I can. I had a quick look and can see there's various files where 1.15 is mentioned and the darwin builds seem to be in .promu-cgo.yml.

Thanks

[SuperQ]

Yes, we do this work by adding it to promu.

[jamesrwhite]

@SuperQ Thanks for looking at this. What's left to add support to node_exporter itself?

I had a go at this myself here but I wanted to check if there was anything else required? I'm happy to make the required changes and open a PR.

We're currently running a darwin/arm64 binary from homebrew that runs fine with the exception of the filesystem collector not being available.

[SuperQ]

I think I finally got the golang-builder working correctly for CGO crossbuilds of the node_exporter.

prometheus/node_exporter#2020

[jamesrwhite]

@SuperQ Just seen the updates to your PR, thanks again for looking at this 👍

I still think some changes like these will be needed to get the filesystem collector working, could you add those in or would you prefer I open a separate PR?

[SuperQ]

Yes, you're right, we need to modify the build flag. Rather than enumerate it, we can change darwin,amd64 to just darwin.

Feel free to open a PR.

[SuperQ]

Actually, I can just add that to the existing PR.