Need to have support for udev in k3os

[chtardif]

Primary use case: OpenEBS/cStor not working without proper udev support in underlying OS

[jstebbins]

FYI, Rook/EdgeFS also needs this to identify devices in a way that is persistent across reboots.

[Alxandr]

Is this hard to add? Or is it just copying another package from upstream alpine (which as far as I've understood k3os is based on)?

[liyimeng]

This is very easy to add, just install it in the base images.
I don’t suggest to have it by default since it increases the initrd size. If you need it, just add it and build from source. Easy job .

[dweomer]

@jstebbins and/or @chtardif If you have a test setup or some guidance (that hopefully doesn't require hours of reading) on how I can assert that your udev use-case is satisfied, I would very much welcome the input. Have any links to share? Also, please try the latest v.0.9.x release candidate!

[jstebbins]

Unfortunately, my use case is rather difficult to set up.

I had previously added udev myself, but I enabled the service by adding this to Dockerfile at the end

+RUN rc-update add udev sysinit
+RUN rc-update add udev-trigger sysinit
+RUN rc-update add udev-settle sysinit

It looks like you enabled the udev service in a different way, but looks like you're missing udev-trigger and udev-settle? TBH, it's been so long I can't remember exactly why I added those last 2. Might just have copied an example I saw elsewhere.

[dweomer]

@jstebbins for some reason i had it in my head that they were triggered so long as udev was present but that doesn't seem to be the case. i will cut another RC with this change.