= meta-updater
:toc: macro
:toc-title:

This layer enables over-the-air updates (OTA) with https://github.com/ostreedev/ostree[OSTree] and https://github.com/advancedtelematic/aktualizr[Aktualizr].

https://github.com/ostreedev/ostree[OSTree] is a tool for atomic full file system upgrades with rollback capability. OSTree has several advantages over traditional dual-bank systems, but the most important one is that it minimizes network bandwidth and data storage footprint by sharing files with the same contents across file system deployments.

https://github.com/advancedtelematic/aktualizr[Aktualizr] (and https://github.com/advancedtelematic/rvi_sota_client[RVI SOTA client]) add authentication and provisioning capabilities to OTA and are integrated with OSTree. You can connect with the open-source https://github.com/advancedtelematic/rvi_sota_server[RVI SOTA server] or sign up for a free account at https://app.atsgarage.com[ATS Garage] to get started.

[discrete]
== Table of Contents

toc::[]

== Build

=== Quickstart

If you don't already have a Yocto project that you want to add OTA to, you can use the https://docs.atsgarage.com/quickstarts/raspberry-pi.html[ATS Garage Quickstart] project to rapidly get up and running on a Raspberry Pi. It takes a standard https://www.yoctoproject.org/tools-resources/projects/poky[poky] distribution, and adds OTA and OSTree capabilities.

=== Adding meta-updater capabilities to your build

If you already have a Yocto-based project and you want to add atomic filesystem updates to it, you just need to do three things:

1.  Clone the `meta-updater` layer and add it to your https://www.yoctoproject.org/docs/current/ref-manual/ref-manual.html#structure-build-conf-bblayers.conf[bblayers.conf].
2.  Clone BSP integration layer (`meta-updater-$\{PLATFORM}`, e.g. https://github.com/advancedtelematic/meta-updater-raspberrypi[meta-updater-raspberrypi]) and add it to your `conf/bblayers.conf`. If your board isn't supported yet, you could write a BSP integration for it yourself. See the <<Adding support for your board>> section for the details.
3.  Set up your https://www.yoctoproject.org/docs/current/ref-manual/ref-manual.html#var-DISTRO[distro]. If you are using "poky", the default distro in Yocto, you can change it in your `conf/local.conf` to "poky-sota". Alternatively, if you are using your own or third party distro configuration, you can add `INHERIT += " sota"` to it, thus combining capabilities of your distro with meta-updater features.

You can then build your image as usual, with bitbake. After building the root file system, bitbake will then create an https://ostree.readthedocs.io/en/latest/manual/adapting-existing/[OSTree-enabled version] of it, commit it to your local OSTree repo and (optionally) push it to a remote server. Additionally, a live disk image will be created (normally named `$\{IMAGE_NAME}.-sdimg-ota` e.g. `core-image-raspberrypi3.rpi-sdimg-ota`). You can control this behaviour through <<sota-related-variables-in-localconf,variables in your local.conf>>.

=== Build in AGL

With AGL you can just add agl-sota feature while configuring your build environment:

....
source meta-agl/scripts/aglsetup.sh -m porter agl-demo agl-appfw-smack agl-devel agl-sota
....

You can then run:

....
bitbake agl-demo-platform
....

and get as a result an `ostree_repo` folder in your images directory (`tmp/deploy/images/$\{MACHINE}/ostree_repo`). It will contain:

* your OSTree repository, with the rootfs committed as an OSTree deployment,
* an `otaimg` bootstrap image, which is an OSTree physical sysroot as a burnable filesystem image, and optionally
* some machine-dependent live images (e.g. `.wic` for Raspberry Pi or `.porter-sdimg-ota` Renesas Porter board).

Although `aglsetup.sh` hooks provide reasonable defaults for SOTA-related variables, you may want to tune some of them.

=== Build problems

Ubuntu users that encounter an error due to missing `Python.h` should install `libpython2.7-dev` on their host machine.

== Supported boards

Currently supported platforms are

* https://github.com/advancedtelematic/meta-updater-raspberrypi[Raspberry Pi3]
* https://github.com/advancedtelematic/meta-updater-minnowboard[Minnowboard]
* https://github.com/advancedtelematic/meta-updater-qemux86-64[Native QEMU emulation]

=== Adding support for your board

If your board isn't supported yet, you can add board integration code yourself. The main purpose of this code is to provide a bootloader that will be able to use https://ostree.readthedocs.io/en/latest/manual/atomic-upgrades/[OSTree's boot directory]. In the meta-updater integration layers we have written so far, the basic steps are:

1.  Make the board boot into http://www.denx.de/wiki/U-Boot[U-Boot]
2.  Make U-boot import variables from /boot/loader/uEnv.txt and load the kernel with initramfs and kernel command line arguments according to what is set in this file.

You may take a look into https://github.com/advancedtelematic/meta-updater-minnowboard[Minnowboard] or https://github.com/advancedtelematic/meta-updater-raspberrypi[Raspberry Pi] integration layers for examples.

Although we have used U-Boot so far, other boot loaders can be configured work with OSTree as well.

== SOTA-related variables in local.conf

* `OSTREE_REPO` - path to your OSTree repository. Defaults to `$\{DEPLOY_DIR_IMAGE}/ostree_repo`
* `OSTREE_OSNAME` - OS deployment name on your target device. For more information about deployments and osnames see the https://ostree.readthedocs.io/en/latest/manual/deployment/[OSTree documentation]. Defaults to "poky".
* `OSTREE_INITRAMFS_IMAGE` - initramfs/initrd image that is used as a proxy while booting into OSTree deployment. Do not change this setting unless you are sure that your initramfs can serve as such a proxy.
* `SOTA_PACKED_CREDENTIALS` - when set, your ostree commit will be pushed to a remote repo as a bitbake step. This should be the path to a zipped credentials file in https://github.com/advancedtelematic/aktualizr/blob/master/docs/credentials.adoc[the format accepted by garage-push].
* `SOTA_CLIENT_PROV` - which provisioning method to use. Valid options are https://github.com/advancedtelematic/aktualizr/blob/master/docs/automatic-provisioning.adoc[`aktualizr-auto-prov`], https://github.com/advancedtelematic/aktualizr/blob/master/docs/implicit-provisioning.adoc[`aktualizr-implicit-prov`], and https://github.com/advancedtelematic/aktualizr/blob/master/docs/hsm-provisioning.adoc[`aktualizr-hsm-prov`]. The default is `aktualizr-auto-prov`. This can also be set to an empty string to avoid using a provisioning recipe.
* `SOTA_CLIENT_FEATURES` - extensions to aktualizr. The only valid options are `hsm` (to build with HSM support) and `secondary-network` (to set up a simulated 'in-vehicle' network with support for a primary node with a DHCP server and a secondary node with a DHCP client).
* `SOTA_SECONDARY_ECUS` - a list of paths separated by spaces of JSON configuration files for virtual secondaries on the host. These will be installed into `/var/sota/ecus` on the device.
* `SOTA_VIRTUAL_SECONDARIES` - a list of paths separated by spaces of JSON configuration files for virtual secondaries installed on the device. If `SOTA_SECONDARY_ECUS` is used to install them, then you can expect them to be installed in `/var/sota/ecus`.

== Usage

=== OSTree

OSTree used to include a simple HTTP server as part of the ostree binary, but this has been removed in more recent versions. However, OSTree repositories are self-contained directories, and can be trivially served over the network using any HTTP server. For example, you could use Python's SimpleHTTPServer:

....
cd tmp/deploy/images/qemux86-64/ostree_repo
python -m SimpleHTTPServer <port> # port defaults to 8000
....

You can then run ostree from inside your device by adding your repo:

....
# This behaves like adding a Git remote; you can name it anything
ostree remote add --no-gpg-verify my-remote http://<your-ip>:<port>

# If OSTREE_BRANCHNAME is set in local.conf, that will be the name of the
# branch. If not set, it defaults to the value of MACHINE (e.g. qemux86-64).
ostree pull my-remote <branch>

# poky is the OS name as set in OSTREE_OSNAME
ostree admin deploy --os=poky my-remote:<branch>
....

After restarting, you will boot into the newly deployed OS image.

For example, on the raspberry pi you can try this sequence:

....
# add remote
ostree remote add --no-gpg-verify agl-snapshot https://download.automotivelinux.org/AGL/snapshots/master/latest/raspberrypi3/deploy/images/raspberrypi3/ostree_repo/ agl-ota

# pull
ostree pull agl-snapshot agl-ota

# deploy
ostree admin deploy --os=agl agl-snapshot:agl-ota
....

=== garage-push

The https://github.com/advancedtelematic/aktualizr[aktualizr repo] contains a tool, garage-push, which lets you push the changes in OSTree repository generated by bitbake process. It communicates with an http server capable of querying files with HEAD requests and uploading them with POST requests. In particular, this can be used with http://www.atsgarage.com/[ATS Garage]. garage-push is used as follows:

....
garage-push --repo=/path/to/ostree-repo --ref=mybranch --credentials=/path/to/credentials.zip
....

You can set `SOTA_PACKED_CREDENTIALS` in your `local.conf` to automatically synchronize your build results with a remote server. Credentials are stored in an archive as described in the https://github.com/advancedtelematic/aktualizr/blob/master/docs/credentials.adoc[aktualizr documentation].

=== aktualizr configuration

https://github.com/advancedtelematic/aktualizr[Aktualizr] supports a variety of https://github.com/advancedtelematic/aktualizr/blob/master/docs/configuration.adoc[configuration options via a configuration file and the command line]. There are two primary ways to control aktualizr's configuration from meta-updater.

First, you can set `SOTA_CLIENT_PROV` to control which provisioning recipe is used. Each recipe installs an appropriate `sota.toml` file from aktualizr according to the provisioning needs. See the <<sota-related-variables-in-localconf,SOTA-related variables in local.conf>> section for more information.

Second, you can write recipes to install additional config files with customized options. A few recipes already exist to address common needs and provide an example:

* link:recipes-sota/config/aktualizr-example-interface.bb[aktualizr-example-interface.bb] will configure aktualizr to connect to an example interface for a legacy flasher. This is intended to be used in conjunction with the `aktualizr-examples` package. See https://github.com/advancedtelematic/aktualizr/blob/master/docs/legacysecondary.adoc[legacysecondary.adoc] in the aktualizr repo for more information.
* link:recipes-sota/config/aktualizr-disable-send-ip.bb[aktualizr-disable-send-ip.bb] disables the reporting of networking information to the server. This is enabled by default and supported by https://app.atsgarage.com[ATS Garage]. However, if you are using a different server that does not support this feature, you may want to disable it in aktualizr.
* link:recipes-sota/config/aktualizr-log-debug.bb[aktualizr-log-debug.bb] sets the log level of aktualizr to 0 (trace). The default is 2 (info). This recipe is intended for development and debugging purposes.

To use these recipes, you will need to add them to your image with a line such as `IMAGE_INSTALL_append = " aktualizr-log-debug "` in your `local.conf`.

== Development configuration

There are a few settings that can be controlled in `local.conf` to simplify the development process:

[options="header"]
|======================
| Option                              | Effect
| `require classes/sota_bleeding.inc` | Build the latest head (by default, using the master branch) of Aktualizr
| `BRANCH_pn-aktualizr = "mybranch"`

`BRANCH_pn-aktualizr-native = "mybranch"` | Build `mybranch` of Aktualizr. Note that both of these need to be set. This is normally used in conjunction with `require classes/sota_bleeding.inc`
| `SRCREV_pn-aktualizr = "1004efa3f86cef90c012b34620992b5762b741e3"`

`SRCREV_pn-aktualizr-native = "1004efa3f86cef90c012b34620992b5762b741e3"` | Build the specified revision of Aktualizr. Note that both of these need to be set. This can be used in conjunction with `BRANCH_pn-aktualizr` and `BRANCH_pn-aktualizr-native` but will conflict with `require classes/sota_bleeding.inc`
| `TOOLCHAIN_HOST_TASK_append = " nativesdk-cmake "` | Use with `bitbake -c populate_sdk core-image-minimal` to build an SDK. See the https://github.com/advancedtelematic/aktualizr#developing-against-an-openembedded-system[aktualizr repo] for more information.
|======================

== QA with oe-selftest

This layer relies on the test framework oe-selftest for quality assurance. Follow the steps below to run the tests:

1. Append the line below to `conf/local.conf` to disable the warning about supported operating systems:
+
```
SANITY_TESTED_DISTROS = ""
```

2. If your image does not already include an ssh daemon such as dropbear or openssh, add this line to `conf/local.conf` as well:
+
```
IMAGE_INSTALL_append = " dropbear "
```

3. Some tests require that `SOTA_PACKED_CREDENTIALS` is set in your `conf/local.conf`. See the <<sota-related-variables-in-localconf,SOTA-related variables in local.conf>> section.

4. To be able to build an image for the grub tests, you will need to install https://github.com/tianocore/tianocore.github.io/wiki/OVMF[TianoCore's ovmf] package on your host system. On Debian-like systems, you can do so with this command:
+
```
sudo apt install ovmf
```

5. Run oe-selftest:
+
```
oe-selftest --run-tests updater
```

For more information about oe-selftest, including details about how to run individual test modules or classes, please refer to the https://wiki.yoctoproject.org/wiki/Oe-selftest[Yocto Project wiki].
