wiki:venice/ubuntu

Version 6 (modified by Tim Harvey, 18 months ago) ( diff )

added note about SSH root access disabled by default

  1. Ubuntu on Venice
    1. Gateworks pre-built Ubuntu based Disk Images for Venice
    2. BSP
    3. Root filesystem
      1. Compressed Disk Image (for flashing onto a board)
      2. ext4 filesystem
    4. Building a Bootable Disk Image

Ubuntu on Venice

This page provides details on running Ubuntu on a Gateworks Venice Board.

Other references:

Gateworks pre-built Ubuntu based Disk Images for Venice

Gateworks provides a pre-built Ubuntu based firmware images for the Venice Family:

Login Information (default)

  • Username: root
  • Password: root

Features:

  • Ubuntu aarch64 core (created via debootstrap)
  • Gateworks Venice Linux kernel
  • eth0 dhcp with a 10 second timeout
  • User: root password: root
  • Packages installed on top of core including:
    • Updated modemmanager/libqmi-utils/libmbim-utils (see ubuntu/modem)
    • Misc wireless: wpasupplicant iw
    • Misc utils: vim can-utils i2c-tools usbutils pciutils screen watchdog binutils
    • Misc network: wget ethtool iperf iperf3 openssh-server iptables
    • Linux firmware
    • Gateworks ​hostapd-conf script
    • Filesystem tools: e2fstools parted
  • first-boot script to grow root filesystem partition and filesystem (useful when putting disk images on removable storage devices)
  • use ifupdown tools instead of netplan (we find them easier to understand and configure)

To install the kernel and root filesystem on a removable block storage device see below.

Notes:

  • By default root ssh access is disabled for security. See This link for info on enabling it

BSP

To build a complete Ubuntu image, including all the boot firmware, start with the Venice BSP page as the easiest option.

Root filesystem

This is to build the rootfs ONLY. To easily build an entire system image, including the boot firmware and Ubuntu, consider the Venice BSP page.

A popular way to create an Ubuntu root filesystem is to use the deboostrap utility on a Debian or Ubuntu host. This tool provides a 2-stage install where the second stage is within a chroot environment using qemu.

Gateworks uses a script to do this which you may find at ​http://github.com/Gateworks/ubuntu-rootfs

Requirements:

  • Linux Ubuntu or Debian System with network connection and sudo permissions

Important notes:

  • We set and use target and distro env variables in step 2 and use those env variables in the remaining steps to make this tutorial more version-agnostic. Please be aware of this and do not deviate from the steps unless or until you completely understand what you are doing.
  • These steps are not always exactly what we do in our script but give you an idea of how you would go about doing it yourself if you wanted to customize something

Steps:

  1. Install pre-requisites: 
    sudo apt-get install qemu-user-static debootstrap binfmt-support
  1. Perform first stage install of minimal filesystem for arm64 architecture: 
    distro=focal
arch=arm64
target=${distro}-${arch}
qemu_arch=aarch64
sudo debootstrap --arch=$arch --foreign $distro $target
# copy qemu binary for the binfmt packages to find it and copy in resolv.conf from host
sudo cp /usr/bin/qemu-${qemu_arch}-static $target/usr/bin
    • See ​http://ports.ubuntu.com/ubuntu-ports/dists/ for a list of current Ubuntu releases: oe 20.04=focal (latest LTS)
    • this minimal rootfs is still missing some core packages and configuration before it can be booted. These steps are taken care of in a 2nd stage install within a chroot shell
    • the chroot shell below will provide network support (inherited from the host)
  1. We now have a minimal Ubuntu rootfs - chroot to it and perform the 2nd stage install: 
    sudo chroot $target
# now we are in the chroot - setup env matching the distro above
distro=focal
export LANG=C
# setup second stage
/debootstrap/debootstrap --second-stage
    • this is the most minimal rootfs we would recommend
  1. (optional) add additional apt package repos: 
    cat <<EOT > /etc/apt/sources.list
deb http://ports.ubuntu.com/ubuntu-ports $distro main restricted universe multiverse
deb http://ports.ubuntu.com/ubuntu-ports $distro-updates main restricted universe multiverse
deb http://ports.ubuntu.com/ubuntu-ports $distro-security main restricted universe multiverse
EOT
    • you may want to customize the above list, depending on your needs. See below for more detail on Ubuntu package feeds
  1. (optional) update package database and setup locales (do not skip this step if you are needing to install any packages for the steps below or otherwise) 
    apt-get update
apt-get -f install # fixup missing package dependencies
apt-get install locales dialog
dpkg-reconfigure locales
  1. Set hostname: 
    echo ${distro}-$(uname -m) > /etc/hostname
  1. set a root passwd so you can login 
    passwd
    • or consider adding a user via adduser: 
      adduser myuser
usermod -a -G tty myuser # add to tty group for tty access
usermod -a -G dialout myuser # add to dialout group for UART access
usermod -a -G sudo myuser # add to sudo group for root access
  1. (optional) configure networking:
    • wired ethernet with DHCP on eth0 
      apt-get install net-tools ifupdown
cat <<EOF >> /etc/network/interfaces
allow-hotplug eth0
auto eth0
iface eth0 inet dhcp

EOF
    • or static IP: 
      apt-get install net-tools ifupdown
cat <<EOF >> /etc/network/interfaces
allow-hotplug eth0
auto eth0
iface eth0 inet static
address 192.168.1.1
netmask 255.255.255.0
gateway 192.168.1.254

EOF
    • or wireless (requires ~3MB of additional packages): 
      apt-get install wpasupplicant iw
cat << EOF >> /etc/network/interfaces
# Wireless interface
auto wlan0
iface wlan0 inet dhcp
        wireless_mode managed
        wireless_essid any
        wpa-driver nl80211
        wpa-conf /etc/wpa_supplicant.conf

EOF
wpa_passphrase <myssid> <mypass> >> /etc/wpa_supplicant.conf
  1. (optional) install some useful packages 
    apt-get install openssh-server # ssh server for remote access
apt-get install can-utils i2c-tools usbutils pciutils # cmdline tools for various hardware support
    • Note that by default root ssh access is disabled for security. See This link for info on enabling it
  1. Exit the chroot shell and remove files we no longer need 
    exit
sudo rm $target/usr/bin/qemu-$qemu_arch-static

At this point you have a directory containing a root filesystem (without kernel) and likely want to install it onto removable storage or the on-board FLASH of a target board. Some intermediate formats that are useful to keep around would be a tarball, perhaps an ext4 filesystem image, or a compressed disk image suitable for flashing in the U-Boot bootloader.

To create a tarball which is the most flexible storage format and can be used for a variety of future installation uses: 

sudo tar --keep-directory-symlink -cvJf focal-venice.tar.xz -C rootfs/ .
  • '--numeric-owner' is required to store user/group as a number instead of a name, your specific use case may require this switch.
  • the '-C rootfs/' is required to eliminate the rootfs directory prefix
  • the sudo is needed to be able to read the root owned files
  • '--keep-directory-symlink' will preserve symbolic links

Compressed Disk Image (for flashing onto a board)

To create a 'Compressed Disk Image' using this tarball see venice/boot#disk-images and to install this onto a board's embedded FLASH see here.

ext4 filesystem

If desired you can create an ext4 filesystem from the directory or tarball. This requires you choose a size for the filesystem. This size can be increased at runtime using resize2fs as long as the partition table has room for it to grow. The advantage of using an as small as possible size is that the time necessary to flash it onto storage is reduced to a minimum (when flashing you have to write the entire ext4 fs but when formatting or resizing it only has to write periodic markers to FLASH).

For a given size (see SIZEMB variable below) you can create a rootfs with: 

SIZEMB=1536 # 1.5GB - expandable later with resize2fs
OUT=rootfs.ext4
# create a file of specific size
truncate -s ${SIZEMB}M ${OUT}
# format it as an ext4 filesystem
mkfs.ext4 -q -F -L rootfs ${OUT}
# mount it to a temporary mount point
tmp_mnt=$(mktemp -d -p/tmp)
mount ${OUT} ${tmp_mnt}
# copy files to it
cp -rup rootfs/* ${tmp_mnt}
# and/or extract files from a tarball
tar -C ${tmp_mnt} -xf linux-venice.tar.xz --keep-directory-symlink
# unmount temporary mount point
umount ${tmp_mnt}
sync
# compress it
gzip -k -f ${OUT}

Note that the pre-built Gateworks images create a minimal root filesystem as well as a partition table that assumes a specific size (matching the smallest eMMC device used on our boards). There is a script similar to the one above that runs on first-boot which expands the last partition to the extents of the device and grows the partition to fill it. See ​https://github.com/Gateworks/ubuntu-rootfs/blob/master/ubuntu-rootfs.sh and look for 'growpart' for details.

Building a Bootable Disk Image

You will want to build your own Ubuntu disk image if you want control over any of the following:

  • Contents of root filesystem (packages and configuration) (see [#debootstrap debootsrap below)
  • Configuration of the Linux kernel (see venice/bsp/kernel)

See venice/boot/disk-images for detailed instructions.

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