pass env vars via /etc/environment

[muhamadazmy]

To unify passing env vars for cloud-init and cloud container we should pass env vars from the /etc/environment file. By providing a write-file option to cloud init as per this post here

https://stackoverflow.com/questions/38044184/how-to-set-system-wide-environment-variable-in-cloud-config-file-on-digital-ocea

[AbdelrahmanElawady]

From the stackoverflow thread it seems to be OS dependent. /etc/environment seems to be working with Ubuntu but on Alpine for example it's in /etc/profile. Do we check what OS we are using or which env file exists and append based on that?

[muhamadazmy]

Yeah i know it's os dependent but was hoping that all distros uses the same file.

• We can't detect the os type of course, and we shouldn't rely on it
• If kernel+initramfs from cloud-container is used, there is no issue because we export the env to the init process
• We only need a standard cloud-init way to do it. Cloud-init then can do detection or whatever to pass env over.
• Maybe check cloud-init docs for details on env otherwise we can't do it

[AbdelrahmanElawady]

After looking into it, it turned out there is no standard way or file that guarantee global environment variables for all processes to use. Cloud-init also does not handle environment variables at all. IMO I think the approaches we are doing now with setting it in containers and passing it as kernel args in VMs are enough.

[muhamadazmy]

I agree:

• There is no standard way to pass env vars to full VMs. There is no such thing also in cloud-init
• The way we do it works only with container like VMs where the VM has no kernel and we provide our own injected kernel+initramfs that can pass env vars to init.

I will close this as won't fix