chore: add mender-client-data-dir.service file

[aduskett]

Both the mender-authd.service and mender-udpated.service files have
mender-client-data-dir.service in the "After=" line. However, this
service file isn't provided by the mender package. Instead, the
mender-client-data-dir.service file currently resides in the
meta-mender repository.

Even though "After" does not mean "required" it can still be confusing
to users as to where this file comes from. Furthermore, a user may not
want the service file to exist at all, as their build setup may create
the /data directory (or /var/lib/mender) during the image creation.

- Move the mender-data-dir.service file into the mender project.
- Rename mender-data-dir.service to mender-client-data-dir.service.
- Add a new option "MENDER_DATA_DIR_SYSTEMD_UNIT" set to OFF by
default. When enabled, the mender-client-data-dir.service file is
added to the MENDER_DATA_DIR_SYSTEMD_UNIT list.

Changelog: None
Ticket: None

[mender-test-bot]

@aduskett, Let me know if you want to start the integration pipeline by mentioning me and the command "start pipeline".

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[aduskett]

@mender-test-bot start pipeline --pr mender/1695

[mender-test-bot]

Hello 😺 I created a pipeline for you here: Pipeline-1545075314

Build Configuration Matrix

Key	Value
BUILD_BEAGLEBONEBLACK	true
BUILD_CLIENT	true
BUILD_QEMUX86_64_BIOS_GRUB	true
BUILD_QEMUX86_64_BIOS_GRUB_GPT	true
BUILD_QEMUX86_64_UEFI_GRUB	true
BUILD_VEXPRESS_QEMU	true
BUILD_VEXPRESS_QEMU_FLASH	true
BUILD_VEXPRESS_QEMU_UBOOT_UEFI_GRUB	true
INTEGRATION_REV	master
MENDER_ARTIFACT_REV	master
MENDER_BINARY_DELTA_REV	master
MENDER_CLI_REV	master
MENDER_CONFIGURE_MODULE_REV	master
MENDER_CONNECT_REV	master
MENDER_CONVERT_REV	master
MENDER_GATEWAY_REV	master
MENDER_REV	pull/1695/head
MENDER_SETUP_REV	master
MENDER_SNAPSHOT_REV	master
MONITOR_CLIENT_REV	master
RUN_INTEGRATION_TESTS	true
TEST_QEMUX86_64_BIOS_GRUB	true
TEST_QEMUX86_64_BIOS_GRUB_GPT	true
TEST_QEMUX86_64_UEFI_GRUB	true
TEST_VEXPRESS_QEMU	true
TEST_VEXPRESS_QEMU_FLASH	true
TEST_VEXPRESS_QEMU_UBOOT_UEFI_GRUB	true

[aduskett]

I'm not sure why this failed as all of the links for the failed tests are not accessible to me.

[lluiscampos]

@aduskett The mender-qa pipeline has access to internal secrets so we cannot make the CI logs public. Here the error:

NOTE: recipe mender-master-git-r0: task do_package: Started
ERROR: mender-master-git-r0 do_package: QA Issue: mender: Files/directories were installed but not shipped in any package:
  /usr/lib/systemd/system/mender-client-data-dir.service
Please set FILES such that these items are packaged. Alternatively if they are unneeded, avoid installing them or delete them within do_install.
mender: 1 installed and not shipped files. [installed-vs-shipped]
ERROR: mender-master-git-r0 do_package: Fatal QA errors were found, failing task.
ERROR: Logfile of failure stored in: /builds/Northern.tech/Mender/build-qemux86-64-uefi-grub/tmp/work/core2-64-poky-linux/mender/master-git/temp/log.do_package.114947
NOTE: recipe mender-master-git-r0: task do_package: Failed
ERROR: Task (/builds/Northern.tech/Mender/meta-mender/meta-mender-core/recipes-mender/mender-client/mender_git.bb:do_package) failed with exit code '1'

Let me know if you need help debugging it

[aduskett]

@aduskett The mender-qa pipeline has access to internal secrets so we cannot make the CI logs public. Here the error:

NOTE: recipe mender-master-git-r0: task do_package: Started
ERROR: mender-master-git-r0 do_package: QA Issue: mender: Files/directories were installed but not shipped in any package:
  /usr/lib/systemd/system/mender-client-data-dir.service
Please set FILES such that these items are packaged. Alternatively if they are unneeded, avoid installing them or delete them within do_install.
mender: 1 installed and not shipped files. [installed-vs-shipped]
ERROR: mender-master-git-r0 do_package: Fatal QA errors were found, failing task.
ERROR: Logfile of failure stored in: /builds/Northern.tech/Mender/build-qemux86-64-uefi-grub/tmp/work/core2-64-poky-linux/mender/master-git/temp/log.do_package.114947
NOTE: recipe mender-master-git-r0: task do_package: Failed
ERROR: Task (/builds/Northern.tech/Mender/meta-mender/meta-mender-core/recipes-mender/mender-client/mender_git.bb:do_package) failed with exit code '1'

Let me know if you need help debugging it

Hey! Thanks for the help! I have no idea what is going on, as a grep for say, mender-authd.service doesn't pull up anything in a FILES list or directory. Where am I supposed to add the new service file?

Thanks so much!

[lluiscampos]

I need to have a look into it at a later time (this week I am busy with something out of regular work). I assigned it to myself 👍

[lluiscampos]

@aduskett This error is from meta-mender, because there we already have a mender-data-dir.service shipped with the recipe and the new one being added in this PR is not handled.

Can you elaborate on the motivation on having this file here? So far we consider it system specific, and that is why we have it in meta-mender for yocto and also install it in mender-convert for Debian images.

If you need it to be in the mender repo for other reason (buildroot?) we could have it conditionally included with CMake and off by default. But still will make more sense for us to keep it in the repo that does the system integration (iow the responsible for creating a /data partition).

[aduskett]

@aduskett This error is from meta-mender, because there we already have a mender-data-dir.service shipped with the recipe and the new one being added in this PR is not handled.

Can you elaborate on the motivation on having this file here? So far we consider it system specific, and that is why we have it in meta-mender for yocto and also install it in mender-convert for Debian images.

If you need it to be in the mender repo for other reason (buildroot?) we could have it conditionally included with CMake and off by default. But still will make more sense for us to keep it in the repo that does the system integration (iow the responsible for creating a /data partition).

Understandable, but then why does mender-authd.service and mender-client.service require mender-client-data-dir.service? Especially if the data directory (or /var/lib/mender) may already be there. It doesn't seem necessary and more tailored to meta-mender specifically, which, in that case, there isn't any documentation about this requirement, or where mender-client-data-dir.service comes from.

[lluiscampos]

Understandable, but then why does mender-authd.service and mender-client.service require mender-client-data-dir.service? (...)

Sorry for the delay in the response - I've been checking this also internally with some colleagues.

The documentation is not crystal clear, but from what I can understand from the man page (and from my local experiments), I believe that After= does not declare a hard dependency, but a soft one - "if the service is there, run it before you run this one". If that is correct, then mender-authd.service and mender-updated.service (I assume you meant "updated" above) do not require mender-client-data-dir.service.

From the sytemd man page:

systemd knows various kinds of dependencies, including positive and
negative requirement dependencies (i.e.  Requires= and Conflicts=) as well
as ordering dependencies (After= and Before=). NB: ordering and
requirement dependencies are orthogonal. If only (...)

With the above I am trying to justify that as it is now is "okey". But all in all @aduskett you have a very valid point and we could have designed this differently - having mender-client-data-dir.service in this repo, installed conditionally by CMAke on some variable, and then use opt-it in in meta-mender and mender-convert.

Can you prepare the work in the three repos (here + meta-mender + mender-convert)? I don't know how much experience you have on yocto, but there we will need to differentiate between old and newer recipes from where they can get the service. I can guide you and review your work but I am pretty busy otherwise as to do the job myself 😃

[lluiscampos]

FYI @TheYoctoJester and @danielskinstad ☝️

[aduskett]

@lluiscampos Absolutely I can. That sounds like an excellent solution. As for my Yocto experience, I have enough to be dangerous :)
What would you like the CMake option name to be?

[lluiscampos]

(...)What would you like the CMake option name to be?

A boolean MENDER_DATA_DIR_SYSTEMD_UNIT, for example?

[aduskett]

(...)What would you like the CMake option name to be?

A boolean MENDER_DATA_DIR_SYSTEMD_UNIT, for example?

ok, this pull request has been updated to use an option. As the option is set to OFF by default, I will make a pull request with the other two repositories once this is merged. Sound good?