Thursday, September 25, 2014

Building Yocto/Poky on openSUSE Factory

Since a few weeks, openSUSE Factory no longer is labeled as "openSUSE Project 13.2", but as:
seife@susi:~> lsb_release -ir
Distributor ID: openSUSE project
Release: 20140918
When trying to build the current Yocto poky release, you get the following Warning:
WARNING: Host distribution "openSUSE-project-20140918" has not been validated with this version of the build system; you may possibly experience unexpected failures. It is recommended that you use a tested distribution.
Now I know these warnings and have ignored those before. The list of tested distributions is hard coded in the build system configuration and in general it would be a bad idea to add not yet released versions (as 13.2) or rolling releases. And since the Factory release number changes every few days, it is clearly impossible to keep this up to date: once you have tested everything, the version has increased already. But apart from this, purely cosmetic warning, there is a really annoying consequence of the version change: the configuration cache of bitbake (the build tool used by Yocto poky/OpenEmbedded) is rebuilt on every change of the host distribution release. Updating the cache takes about 2 minutes on my machine, so doing a simple configuration check on your already built Yocto distribution once a week can get quite annoying. I looked for a solution and went for the "quick hack" route:
  • bitbake parses "lsb_release -ir"
  • I  replace "lsb_release" with a script that emits filtered output and is before the original lsb_release in $PATH
This is what I have put into ~/bin/lsb_release (the variable check is a bit of paranoia to let this only have an effect in a bitbake environment):

if [ -z "$BB_ENV_EXTRAWHITE" -o "x$1" != "x-ir" ]; then
        exec lsb-release $@
printf "Distributor ID:\topenSUSE project\nRelease:\t2014\n"

Then "chmod 755 ~/bin/lsb_release" and now the warning is
WARNING: Host distribution "openSUSE-project-2014" has not been validated...
And more important: it stays the same after updating Factory to the next release. Mission accomplished.

UPDATE: Koen Kooi noted that "Yocto" is only the umbrella project and what I'm fixing here is actually the "poky" build system that's part of the project, so I edited this post for clarity. Thanks for the hint!

Friday, September 19, 2014

Fix openSUSE's grub2 for Virtualization and Servers

After installing current openSUSE Factory in a VM, I found that the old GRUB option was removed from YaST2. I knew this from the mailing list, but now I actually realized that this happened. I still prefer GRUB over GRUB2, because for me it is easier to manage. But being lazy, I just went with the default.
Everything went well, until I added a customized kernel (I had installed the VM to do some kernel experiments after all). The boot menu suddenly was not very useful anymore. After selecting "advanced options", I got the following:
Well, which one of the four is now my hand-built, brand new kernel?
There is no such thing as in old GRUB where "Esc" got you out of gfxboot mode and into text mode. The command keys, like "e" for editing the current selection and "c" for a GRUB2 shell (something even more hellish than the old GRUB shell apparently) work, but you really need to know this, as there is no indication of that.

So I wanted to get rid of the gfxboot stuff. I don't need fancy, I need it usable.
Booted the VM, logged in. "zypper rm grub2-branding-openSUSE" followed by "grub2-mkconfig > /boot/grub2/grub.cfg". Much better:
But still it is in graphics mode, which I do not care about now, but once I have to deploy this stuff on something like an HP server where you can get a text console via SSH, but only if it is in plain VGA mode, I will not be amused. So boot that VM again, and look further. Finally, the solution is in /etc/default/grub: "GRUB_TERMINAL=console". The comment above says just uncommenting the original "gfxterm" setting would be enough, but it is not. After recreating the config file and rebooting, it looks quite useful:
And it is not even missing information, compared to the gfxterm version... no idea why this stuff is default.

Now that "Distribution" string in there looks completetly redundant, so getting rid of that will help, too.
Again, it is in /etc/default/grub, variable GRUB_DISTRIBUTOR. I see that in the grub2 rpm package, there is only "openSUSE" instead of  "openSUSE Factory Distribution", so it might be put into the config by the installer or something. I'll change it to just "Factory" (to distinguish between other openSUSE installations). After grub2-mkconfig, it looks almost good:
Now the important information (Kernel version) is completely visible. Much better than the original "bling bling" screen, which had no useful information at all...
Just fixing the Factory string would probably have helped also, but it still would fail the server test, so plain console will stay my favorite for now.