Re: [docs] [PATCH 1/2] ref-manual: add overlayfs-etc class

[Quentin Schulz <foss@0leil.net>]

Hi Vyacheslav,

On December 15, 2021 6:11:37 PM GMT+01:00, Vyacheslav Yurkov <uvv.mail@gmail.com> wrote:
>Signed-off-by: Vyacheslav Yurkov <uvv.mail@gmail.com>
>---
> documentation/ref-manual/classes.rst | 41 ++++++++++++++++++++++++++++
> 1 file changed, 41 insertions(+)
>
>diff --git a/documentation/ref-manual/classes.rst b/documentation/ref-manual/classes.rst
>index 2c191f407..a5b01c2cf 100644
>--- a/documentation/ref-manual/classes.rst
>+++ b/documentation/ref-manual/classes.rst
>@@ -1769,6 +1769,47 @@ to the unit the following::
> .. note::
> 
>    The class does not support the ``/etc`` directory itself, because ``systemd`` depends on it.
>+   In order to get ``/etc`` in overlayfs see :ref:`overlayfs-etc <ref-classes-overlayfs-etc>` 
>+

Missing dot at the end of the sentence.

>+.. _ref-classes-overlayfs-etc:
>+
>+``overlayfs-etc.bbclass``
>+=========================
>+
>+In order to have ``/etc`` directory in overlayfs a special handling at early 
>+boot stage is required.  The idea is to supply a custom init script that mounts
>+``/etc`` before launching actual init program, because the latter already
>+requires ``/etc`` to be mounted
>+

Missing dot at the end of the sentence.

>+.. note::
>+
>+   This class must not be inherited directly. Use corresponding IMAGE_FEATURE
>+

Missing dot at the end of the sentence.

>+Your machine configuration should define at least device, mount point, and file system type
>+you are going to use for ``overlayfs``::
>+
>+  OVERLAYFS_ETC_MOUNT_POINT = "/data"
>+  OVERLAYFS_ETC_DEVICE = "/dev/mmcblk0p2"
>+  OVERLAYFS_ETC_FSTYPE ?= "ext4"
>+
>+To control more mount options you should consider setting mount options
>+(``defaults`` is used by default)::
>+
>+  OVERLAYFS_ETC_MOUNT_OPTIONS = "wsync"
>+
>+The class provides two options for ``/sbin/init`` generation:
>+
>+* Default option is to rename original ``/sbin/init`` to ``/sbin/init.orig`` and
>+  place generated init under original name, i.e. ``/sbin/init``. It has an advantage
>+  that you won't need to change any kernel parameters in order to make it work,
>+  but it poses a restriction that package-management can't be used, becaause updating
>+  init manager would remove generated script

What is the default value? This needs to be explicit otherwise it cannot be "undone" in a bbappends for example.

Thanks for the patch,
Cheers,
Quentin

>+* If you are would like to keep original init as is, you can set::
>+
>+   OVERLAYFS_ETC_USE_ORIG_INIT_NAME = "0"
>+
>+  Then generated init will be named ``/sbin/preinit`` and you would need to extend your
>+  kernel parameters manually in your bootloader configuration.
> 
> .. _ref-classes-own-mirrors:
>