This section provides an overview of the variables that mender-convert uses during the conversion process.

You can override any option specified here by providing your own configuration file using the '--config' argument.

IMAGE_OVERHEAD_FACTOR

Value: 1.5 (default)

This factor is multiplied by the used space value for the generated rootfs, and if the result is larger than IMAGE_ROOTFS_SIZE + IMAGE_ROOTFS_EXTRA_SPACE, it will be used as the size of the rootfs instead of the other two variables.

The actual free space will usually be lower than requested. See comment for IMAGE_ROOTFS_EXTRA_SPACE.

This variable directly mirrors the variable from the Yocto Project, which is why it is missing a "MENDER_" prefix.

IMAGE_ROOTFS_EXTRA_SPACE

Value: 0 (default)

The amount of extra free space requested on the rootfs, in KiB. This is added to the value of IMAGE_ROOTFS_SIZE. The size is further modified by IMAGE_OVERHEAD_FACTOR.

Note that due to reserved space for the root user on the filesystem, "df" may report a significantly lower number than requested. A more accurate number can be fetched using for example dumpe2fs and looking for the Free blocks field, but even this value is usually going to be lower than requested due to meta data on the filesystem.

This variable directly mirrors the variable from the Yocto Project, which is why it is missing a "MENDER_" prefix.

IMAGE_ROOTFS_SIZE

Value: 0 (default)

The size of each of the two rootfs filesystems, in KiB. If this is 0, mender-convert will use the size of the filesystem content as a basis. If the value is -1, mender-convert will use the maximum size that will fit inside the created partition. The size is further modified by IMAGE_ROOTFS_EXTRA_SPACE and IMAGE_OVERHEAD_FACTOR.

This variable directly mirrors the variable from the Yocto Project, which is why it is missing a "MENDER_" prefix.

MENDER_ARTIFACT_COMPRESSION

Values: gzip(default)/lzma/zstd_fast/zstd_fastest/zstd_better/zstd_best/none

The compression algorithm to use when generating the Artifact. In general LZMA will produce a smaller Mender Artifact (2-3x) but will significantly increase time spent generating the Mender Artifact (10x), compared to gzip.

Zstd provides different compression levels, and can achieve comparable compression ratios to both gzip and LZMA, at faster compression and decompression throughput. zstd_fast is the default. See https://engineering.fb.com/2018/12/19/core-data/zstandard for details.

MENDER_ARTIFACT_NAME

Value: <release-name>

Explicitly set the name of the generated update Artifact. Required for the conversion to succeed. However, should be specified on the command line, and not in the configuration.

MENDER_BOOT_PART

Value:

This option allows fine grained control of the boot partition device path and overrides MENDER_STORAGE_DEVICE and MENDER_BOOT_PART_NUMBER settings. If part-uuid is used then you will need to also enable MENDER_ENABLE_PARTUUID

Examples:

/dev/sda1
/dev/disk/by-partuuid/26445670-f37c-408b-be2c-3ef419866620
/dev/disk/by-partuuid/26445670-01

MENDER_BOOT_PART_NUMBER

Value: 1 (default)

Set the default index for the boot partition.

MENDER_BOOT_PART_SIZE_MB

Value: 40 (default)

The size of the boot partition.

MENDER_CLIENT_INSTALL

Value: y(default)/n

Install the Mender client.

MENDER_CLIENT_VERSION

Value: latest(default)/master/<version>

The version of the Mender client to include in the update.

MENDER_ADDON_CONNECT_INSTALL

Value: y/n(default)

Install the Mender Connect add-on.

MENDER_ADDON_CONNECT_VERSION

Value: latest(default)/master/<version>

The version of the Mender Connect add-on to include in the update.

MENDER_ADDON_CONFIGURE_INSTALL

Value: y/n(default)

Install the Mender Configure add-on.

MENDER_ADDON_CONFIGURE_VERSION

Value: latest(default)/master/<version>

The version of the Mender Configure add-on to include in the update.

MENDER_COMPRESS_DISK_IMAGE

Values: gzip/lzma/none

This is useful when you have large disk images, compressing them makes it easier to transfer them between a build server and a local machine, and saves space.

The default behavior is to deduce it from the input image. For an uncompressed input image, the default value will be none. For a compressed image, the default value will be lzma or gzip, depending on the input image compression.

MENDER_DATA_PART

Value:

This option allows fine grained control of the data partition device path and overrides MENDER_STORAGE_DEVICE and MENDER_DATA_PART_NUMBER settings. If part-uuid is used then you will need to also enable MENDER_ENABLE_PARTUUID

Examples:

/dev/sda4
/dev/disk/by-partuuid/26445670-f37c-408b-be2c-3ef419866623
/dev/disk/by-partuuid/26445670-04

MENDER_DATA_PART_FSTAB_OPTS

Values: defaults/<fstab specific options>

Options passed on to fstab.

MENDER_DATA_PART_GROWFS

Values: y(default)/n

Enable/Disable automatically growing the filesystem to fill the physical storage device.

MENDER_DATA_PART_NUMBER

Value: 4 (default)

Set the index of the data partition.

MENDER_DATA_PART_SIZE_MB

Value: 128 (default)

The size of the Mender data partition.

MENDER_DEVICE_TYPE

Value: <device-type>

Set the device type specified by the Artifact. If left empty it will default to the value of '/etc/hostname'.

MENDER_ENABLE_PARTUUID

Values: y/n(default)

This option enables the use of partuuid's as partition block device references. The variables MENDER_BOOT_PART, MENDER_ROOTFS_PART_A, MENDER_ROOTFS_PART_B and MENDER_DATA_PART should also be set in conjunction with this variable to ensure reproducible builds with the same part-uuids.

MENDER_ENABLE_SYSTEMD

Values: y(default)/n

If you want the Mender client to operate in managed mode and connect to a server, then this should be enabled. If you are not interested connecting to a server and will only be running standalone mode updates, then you can safely disable this.

MENDER_GITHUB_ORG

Value: https://github.com/mendersoftware (default)

The URL prefix for looking up the mendersoftware dependencies.

MENDER_KERNEL_DEVICETREE

Value: kernel.dtb (default)

Set the name of the kernel devicetree file.

MENDER_PARTITION_ALIGNMENT

Value: 8388608 ( 8MB, default)

The partition alignment expressed in bytes.

MENDER_ROOTFS_PART_A

Value:

This option allows fine grained control of the first (A) rootfs partition device path and overrides MENDER_STORAGE_DEVICE and MENDER_ROOTFS_PART_A_NUMBER settings. If part-uuid is used then you will need to also enable MENDER_ENABLE_PARTUUID

Examples:

/dev/sda2
/dev/disk/by-partuuid/26445670-f37c-408b-be2c-3ef419866621
/dev/disk/by-partuuid/26445670-02

MENDER_ROOTFS_PART_A_NUMBER

Value: 2 (default)

Set the default index of the rootfs part-A partition.

MENDER_ROOTFS_PART_B

Value:

This option allows fine grained control of the first (B) rootfs partition device path and overrides MENDER_STORAGE_DEVICE and MENDER_ROOTFS_PART_B_NUMBER settings. If part-uuid is used then you will need to also enable MENDER_ENABLE_PARTUUID

Examples:

/dev/sda3
/dev/disk/by-partuuid/26445670-f37c-408b-be2c-3ef419866622
/dev/disk/by-partuuid/26445670-03

MENDER_ROOTFS_PART_B_NUMBER

Value: 3 (default)

Set the default index of the rootfs part-B partition.

MENDER_STORAGE_DEVICE

Value: /dev/mmcblk0p (default)

Set the device file corresponding to the root filesystem partitions.

MENDER_STORAGE_TOTAL_SIZE_MB

Value: 8192 (default)

The size of the storage medium of the device.

MENDER_STORAGE_URL

Value: https://downloads.mender.io (default)

The source of the binaries employed by the Mender-convert tool.

MENDER_USE_BMAP

Values: y/n (default)

Enable/Disable the usage of bmap index in the generated image.