Thanks + questions

[kennethlimcp]

Hey @umiddelb,

great work for the documentation! Really interesting and helps me figure out what went wrong for my image.

I have a question if you can help me along:

1.) I did not compile my own kernel (so no aufs)
2.) Using a Odroid-C1 minimal from http://odroid.com/dokuwiki/doku.php?id=en:c1_ubuntu_minimal

I have a few errors like CONFIG_CGROUP_CPUACCT: missing in my attempt to fire up a container with your armhf image. (checked using the https://github.com/docker/docker/blob/master/contrib/check-config.sh)

Did you experience something similar on the C1 or is there something that i have overlooked?

3.) I used the binary for the 1.5.0 docker version you compiled

Thanks!!

[umiddelb]

The kernel image provided by hardkernel isn't prepared for docker use. As long as the requirements marked as 'Generally Necessary' are not met, docker won't start. In other words, you need to compile your own kernel. The easiest way to do this is to take the kernel sources from my github repository which includes the necessary kernel options as well as aufs support:

git clone https://github.com/umiddelb/linux --single-branch -b odroidc-3.10.y
cd linux
make odroidc_defconfig
make -j 4 uImage modules
make dtbs
sudo make modules_install
sudo cp arch/arm/boot/uImage /media/boot
sudo cp arch/arm/boot/dts/meson8b_odroidc.dtb /media/boot
sudo init 6

and you're done.

[umiddelb]

If you really don't want to compile a custom kernel, you may try my minimal image for the c1 here. It has builtin docker support.

[kennethlimcp]

Thanks for the information! In the wiki you mentioned that we can do it using the kernel provided by hardkernel.

Is that still possible now that the source you recommended is the kernel from your repo?

Also, can you share how those requirements are patched so that I can learn something new?

Thanks! :)

[umiddelb]

I have to be more precise, 'kernel provided by hardkernel' means the kernel source files. You have to modify the kernel configuration at least. But you really want to include aufs support, it will speed up container related operations dramatically.

My sources are in sync with upstream (with the exception of aufs support of course), you can see this on github. There are two modifications:

1. I've enabled kernel options needed for docker to start properly. This step doesn't require patching source files, you enable certain kernel configurations (which are disabled by the vendor) only. check-config.sh will tell you the missing options (e.g. CONFIG_CGROUP_CPUACCT).
2. I've integrated aus support. This requires patching the kernel sources.

All of this is already done in my fork of the kernel sources.

[kennethlimcp]

Got it! I probably should take a look at how you enabled those configuration.

It will be easy now that you have done most of the heavylifting!

It's on my to learn list on for compiling a distro from source so i guess the has come for me to do it!

Thanks for your patience though with a beginner :)

[umiddelb]

This is only about how to compile a custom kernel which is expected to happen on the ARM platform.
On the i386 or amd64 platform the mainstream distributions have included almost everything in their kernel images which makes compiling your own kernel very unlikely. On ARM storage requirements matter (especially when you want to put your kernel image in NAND flash memory), so the vendors publish kernel configurations which lead to smaller images.

If you want to compile the whole distribution (not only the kernel) then you should become familiar with gentoo or 'linux from scratch' (or even freebsd). ubuntu, archlinux, debian or fedora use precompiled packages.

[kennethlimcp]

@umiddelb, just took a look at your forked kernel repo and it is even with the upstream.

I don't see where are the changes you did to enable the cgroups requirement.

Or they are enabled by default already on the upstream kernel?

[umiddelb]

The kernel configuration is stored in a file named .config
The command make odroidc_defconfig will generate a new version of the file derived from a template file. You can find this template in ./arch/arm/configs/odroidc_defconfig. You can find the modifications I made to the kernel config there.

https://github.com/umiddelb/linux/commit/49df9ea7f36303c4221d04e9d581938b8d876b0c#diff-9a711c0d0e135f2c8bd55323133b09c1

[kennethlimcp]

@umiddelb, i saw the changes to odroid_defconfig in the commit but looking at the latest branch odroidc3.10.y which you recommended for kernel compilation, the settings are not there and defaults to hardkernel version.

Am i missing something? 👯

Was unable to locate the .config file mentioned. I presume if i grab the branch using instructions here: #2 (comment), it should work? I'm just curious where's the actual changes made though i can see what you have done in that particular commit.

https://github.com/umiddelb/linux/blob/odroidc-3.10.y/arch/arm/configs/odroidc_defconfig

[umiddelb]

@kennethlimcp

please try it again, it should work now:

git clone https://github.com/umiddelb/linux --single-branch -b odroidc-3.10.y
cd linux
make odroidc_defconfig
make -j 4 uImage modules
make dtbs
sudo make modules_install
sudo cp arch/arm/boot/uImage /media/boot
sudo cp arch/arm/boot/dts/meson8b_odroidc.dtb /media/boot
sudo init 6

You can see the differences here, just scroll down until odroidc_defconfig begins (search for arch/arm/configs/odroidc_defconfig in your browser) ...

[kennethlimcp]

@umiddelb, cool! guess when you merged upstream it got reverted back to the default file that's why i didn't see it. Hope it ends up in the hardkernel repo :)

Thanks for the help! I'll try to compile them tonight and update you again

[umiddelb]

@kennethlimcp

It's merged into the hardkernel repo now.

[kennethlimcp]

@umiddelb, just wanted to build and realized your linux repo is gone! Are you recommended the Hardkernel repo instrad? :)

[umiddelb]

@kennethlimcp

yes of course, It's the official source for the c1 linux kernel. There is no reason to have a fork since the pull request is processed successfully.

[kennethlimcp]

Some errors with make odroidc_defconfig though on Mac osx:

10 warnings generated.
  HOSTCC  scripts/kconfig/zconf.tab.o
  HOSTLD  scripts/kconfig/conf
***
*** Can't find default configuration "arch/x86/configs/odroidc_defconfig"!
***
make[1]: *** [odroidc_defconfig] Error 1
make: *** [odroidc_defconfig] Error 2

not sure why its referencing to x86

AH! Had to use this make odroidc_defconfig ARCH=arm