The kirkstone branch of meta-mender, Mender’s Yocto Project layer, has been released. The main feature of this release is compatibility with the Yocto branch of the same name, which is their latest LTS release. Branches in meta-mender are maintained according the same schedule, which means that the meta-mender kirkstone branch is an LTS release, supported until at least April 2024.
At the same time, support for the zeus and warrior branches is dropped. We still accept pull requests for them, but they become community maintained, and are no longer supported by Mender.
In addition to compatibility, there are numerous smaller features, additions and changes contained in this release, some of which require adjustments to existing build configurations. Below is a breakdown of the most important ones.
Default Update Modules
Several Update Modules are now installed by default. Update Modules allow different types of updates besides the built-in rootfs update mechanism, such as updating single files, installing entire folders, installing packages, or updating Docker containers.
These Update Modules are installed by default
To disable the automatic installation of these Update Modules, add PACKAGECONFIG_remove = "modules" to your mender_%.bbappend file, or set PACKAGECONFIG explicitly.
MENDER_CERT_LOCATION variable deprecated/removed
The MENDER_CERT_LOCATION has been deprecated and removed. To install a custom certificate for the client, either install it through another recipe into the ca-certificates area, or make a mender-server-certificate.bbappend recipe and add SRC_URI = "file://server.crt" to it.
grub-mender-grubenv tools renamed
Mender’s tools for manipulating the boot environment when GRUB integration is enabled, have been renamed. This was done to avoid conflict with the u-boot-fw-utils package, whose tools have the same names. The tools, which used to be named fw_printenv and fw_setenv, are now called grub-mender-grubenv-print and grub-mender-grubenv-set, respectively.
This is unlikely to affect many users unless you have scripts which use the same tools.
However, it means that it is now possible to install the grub-mender-grubenv and u-boot-fw-utils packages at the same time. This can be useful in certain advanced ARM board scenarios where U-Boot is used to load GRUB as a UEFI app, and access to both boot environments is needed.
Support for systemd-boot
It is now possible to use systemd-boot with mender by turning off mender-grub and mender-uboot features and turning on mender-systemd-boot:
MENDER_FEATURES_DISABLE:append = " mender-grub mender-uboot"
MENDER_FEATURES_ENABLE:append = " mender-systemd-boot"
Note that this is a contributed feature, and it is not officially supported by Mender.
Mender-binary-delta
It is no longer necessary to unpack the .tar.xz file before including Mender’s mender-binary-delta software in the Yocto build. In fact, it is no longer supported. Lines starting with FILESEXTRAPATHS_pn-mender-binary-delta should be removed from the configuration and replaced with the line below instead.
SRC_URI:pn-mender-binary-delta = "file://${HOME}/mender-binary-delta-1.4.0.tar.xz"
Adjust the file path to where your .tar.xz file is. Note that the two slashes after file: are not part of the path. If you are providing an absolute path, there will be three slashes after file:.
Note also the recent license acceptance changes which were documented on Mender Hub. Those changes are not specific to kirkstone though.