[yocto] Whats the better way to maintain the Yocto project for an embedded product - git submodules or repo or using Combo-layer

[Paul Barker]

On 18 January 2017 09:32:15 GMT+00:00, "Eswaran Vinothkumar (BEG-PT/PJ-IOT1)" <Vinothkumar.Eswaran at de.bosch.com> wrote:
>Hello Yocto community members,
>
>Currently I am working on the task of using Yocto to build customized
>Embedded Linux distribution for an embedded product. I have created a
>new BSP layer for my project (meta-custommachine) and have successfully
>created barebox, Linux Kernel and root filesystem images for my board.
>
>Now I wish to create an internal repository for Yocto project to track
>and maintain the changes. I am unclear what is the better way to create
>an repository. I googled for the same and found that the Freescale
>community is maintaining their Yocto project using the repo tool. So I
>tried to have a similar structure for my project. I created a repo with
>the default.xml file which has the information about where to fetch the
>repositories for poky, meta-ptx and meta-custommachine. I am seeing the
>folder structures as expected and build is also fine.
>
>I had a discussion with one of my senior team member about this and he
>is interested in using git submodules. So I tried to add the layers
>meta-custommachine and meta-ptx within poky repository as sub-modules.
>Is this the proper way of adding new layers within the poky repository?
>Or may I know how can I maintain a Yocto repository using git
>submodules. Does git submodules work better than repo tool ?
>
>I am newbie to create and maintain a repo, so I am not able to
>visualize what is the future effect of choosing one over the other.
>Currently I am using the krogoth release of Yocto and planning to
>update this with new Yocto releases.
>
>Any information on the topic would be helpful.

Both of these approaches are widely used, I'd go with whichever feels most comfortable to you/your team. Personally I'm a fan of using repo as I can set it to check out the latest commits on a given branch (eg. krogoth) instead of always having to set an exact commit hash to use.

If using git submodules it is often advised to have a separate top level repository which just pulls in the submodules.