dfall_install_instructions_for_raspberry_pi.md

Raspberry Pi Installation

CREATE THE SD CARD WITH THE PRE-INSTALLED UBUNTU SERVER IMAGE

This step is to flash the Ubuntu 18.04 image onto the SD card for the Raspberry Pi. The following instructions are taken from the Raspberry Pi website: https://www.raspberrypi.org/documentation/installation/installing-images/

Download the latest Ubuntu 18.04 (server version) from either of these two Ubuntu pages: https://www.ubuntu.com/download/iot/raspberry-pi-2-3 https://wiki.ubuntu.com/ARM/RaspberryPi

Uncompress the downloaded file using the appropriate tool available on your operating system (Windows: 7-Zip, Mac: The Unarchiver, Linux: Unzip)

Proceed as follows for Mac:

Insert the SD card into your computer, open the Disk Utility application, and format the SD card with options: Format: MS-DOS (FAT) Scheme: Master Boot Record

Open teminal and use the command diskutil list to identify which disk coresponds to the SD card, where you are looking for the label of the form disk2 and NOT the label of the form disk2s1

Unmount all partitions of the SD card using the command

diskutil unmountDisk /dev/disk<disk# from diskutil>

Copy the Ubuntu image to the SD card using the command

sudo dd bs=1m if=~/Downloads/image.img of=/dev/rdisk<disk# from diskutil> conv=sync

The copying will take a few minutes and not display any status infromation. It is possible to retireive the current progress by pressing Ctrl+T to send the SIGINFO signal to the respective terminal where the command is running.

Once the copy has completed, eject the SD card using the command:

sudo diskutil eject /dev/rdisk<disk# from diskutil>

CHANGE THE BOOT-LOADER FOR RASPBERRY PI 3 B+

Insert the SD card into your computer and open the config.txt file in your favourite editor. Adjust the lines:

kernel=...
device_tree_address=0x02000000

to instead be

kernel=vmlinuz
initramfs initrd.img followkernel
#device_tree_address=0x02000000

This step was taken from: https://www.raspberrypi.org/forums/viewtopic.php?t=233794

FIRST BOOT OF UBUNTU ON THE RASPBERRY PI

This step is to insert the SD card into the Raspberry Pi, boot it up, and setup the Ubuntu installation. For this first boot it is required to have a wired internet connection that does not require any authentification.

After booting you are prompted to enter the username and password, which are ubuntu and ubuntu respectively. You are then asked to change the password.

After entering the new password there is sometimes the error Authentication token manipulation error, the screen clears, and you are again prompted for the username and password. This error relates to some problem with the write access for setting the new password. To overcome this error, shutdown the Raspberry Pi (simply unplug the power), remove the SD card and insert the SD card into your computer. Open the cmdline.txt using your favourite editor and add the following at the end of the line:

 init=/bin/sh

NOTE: this cmdline.txt file should be use one line of text, and each command should separated by a space. So if the file orginally looks like:

previous content of file

Then the file after editing should look like:

previous content of file init=/bin/sh

Put the SD card back into the Raspberry Pi and power it up. A few boot steps are performed and then you are presented with a cursor. At the prompt type the following command (if you are presented with an error message, then simply type the command again):

mount -o remount, rw /

The results should be a message something like:

EXT4-fs (mmcblk0p2): re-mounted. 0pts: (null)

Now update the password for the ubuntu user using the command:

passwd ubuntu

You are prompted to enter the new password twice, and then the following message should be displayed:

passwd: password updated successfully

Now type the following commands:

sync
exec /sbin/init

The Raspberry Pi now continues to boot normally, and you can log into with the username ubuntu and the new password you set.

Shut down the Raspberry Pi using the command:

sudo halt

Remove the SD card from the Raspberry Pi, insert the SD card into your computer, open the cmdline.txt file again, and remove the init=/bin/sh that you added.

Eject the SD card from your computer, insert the SD card into the Raspberry Pi, and you are good to go with your new password and normal booting.

These steps to reset the password were taken from: https://www.raspberrypi-spy.co.uk/2014/08/how-to-reset-a-forgotten-raspberry-pi-password/

UPGRADE ALL SOFTWARE

This may be started automatically, and when you try the commands:

sudo apt update
sudo apt list --upgradable
sudo apt upgrade

you may get the error:

E: Could not get lock /var/lib/dpkg/lock - open (11 Resource temporarily unavailable)
E: Unable to lock the administration directory (/var/lib/dpkg/) is another process using it?

The answer is yes, another process is using dpkg and hence it is locked, and it is likely that the process is the automatic daily apt upgrade service. To list all the automatic timers managed by the system, enter the command:

systemctl list-timers

On the list you are like to see apt-daily.timer and apt-daily-upgrade.timer. Alternatively, to check if the timers, and the services they trigger, are active, enter the following commands:

systemctl is-active apt-daily.timer
systemctl is-active apt-daily.service
systemctl is-active apt-daily-upgrade.timer
systemctl is-active apt-daily-upgrade.service

If the services are active, then it is recommended to allow time for them to complete, and then disable the services and timers with the following commands:

sudo systemctl disable apt-daily.service
sudo systemctl disable apt-daily.timer
sudo systemctl disable apt-daily-upgrade.timer
sudo systemctl disable apt-daily-upgrade.service

FAILED TO START LOAD KERNEL MODULES ERROR

While booting, one item is listed in red as FAILED with the message:

Failed to start Load Kernel Modules

Once logged in, run the following command to list the various system units and their status:

systemctl list-units

In the list you should see the unit system-modules-load.service that is described as Load Kernel Modules and is indicated as loaded but the active and sub flags are both failed. You can get more information about this error by using the command:

systemctl status systemd-modules-load.service

The status that is printed out will likely indicate the error as:

Failed to find module ib_iser

Looking through various forums posts about this error message, it seems the best course of action is to edit the file:

nano /lib/modules-load.d/open-iscsi.conf

and comment out the ib_iser line, i.e., change the line to #ib_iser. You can then test if this resolves the error by either a reboot, or by restarting the service and then checking its status with the following commands:

systemctl restart systemd-modules-load.service
systemctl status systemd-modules-load.service

Note that even if left un-resolved, this error does not prevent the installation and running of ROS-Melodic and the D-FaLL-System software.

CREATING AND ENABLING A SWAP FILE

Whether or not you plan to run resource hungry software (for example web-browsing), it can be useful to create a swap file partition to avoid out-of-memory errors. Although using a swap file for memory is much slower than the on-board RAM, and may cause the SD card to wear out quicker, it does avoid a system crash during those operations that require high memory.

Create the swap file with the following commands

sudo fallocate -l 1G /swapfile
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile

Specify that the swap file is to be use by adding the following entry to /etc/fstab:

/swapfile swap swap defaults 0 0

Using sudo nano /etc/fstab is a easy wasy to edit the file, and using less /etc/fstab is an easy way to check that the edits were correctly saved.

Reboot the Raspberry Pi (simply use the command reboot). And upon rebooting, check that the swap file is available using the command:

sudo swapon --show

The outpuut should look something like:

NAME      TYPE  SIZE USED PRIO
/swapfile file 1024M   0B   -2

This step was also taken from: https://www.raspberrypi.org/forums/viewtopic.php?t=233794

REMOVING THE CLOUD INIT SERVER CAPABILITY

As the Ubuntu image is a server image, it comes pre-installed with cloud-init. The boot time of the Raspberry Pi can be slower due to cloud-init, so if you do not plan to actually use the Raspberry Pi as a server, then cloud-init can be safely removed with the following commands:

sudo rm -rf /etc/cloud/
sudo apt purge cloud-init

This step was also taken from: https://www.raspberrypi.org/forums/viewtopic.php?t=233794

INSTALL A GRAPHICAL DESKTOP INTERFACE

For example:

sudo apt-get install lubuntu-desktop

Other desktops are available, for example xubuntu-desktop and kubuntu-desktop, but the D-FaLL-System has only been tested to work with lubuntu-desktop. Note that this can take upto an hour to install.

ADD REPOSITORIES FOR MAIN, UNIVERSE, MULTIVERSE, RESTRICTED

These should already be added by default, but you can check they are added by simply trying to add them (again) using the following commands:

sudo add-apt-repository main
sudo add-apt-repository universe
sudo add-apt-repository multiverse
sudo add-apt-repository restricted

If any of these were not already added, then run sudo apt update and upgrade.

INSTALL THE D-FaLL-System

Download the appropriate installation script

dfall_install_ros_melodic_ubuntu18_raspberry_pi.sh

Change the permissions of the file to make it executable using the command

chmod +x dfall_install_ros_melodic_ubuntu18_raspberry_pi.sh

Run the installation script using the command

./dfall_install_ros_melodic_ubuntu18_raspberry_pi.sh

SETUP THE FIXED IP ADDRESS

The networking is handled by netplan and hence network specifications are contained in the /etc/netplan folder. As installed, this folder should contain only one file named 50-clound-init.yaml, and the contents of the file should look something like:

network:
    version: 2
    ethernets:
        eth0:
            dhcp4: true
            match:
                macaddress: xx:xx:xx:xx:xx:xx
            set-name: eth0

If using a desktop environment, then you specify that the network-manager provided by the desktop is in charge of managing connections by editing the file to be:

network:
    version: 2
    renderer: NetworkManager

To make this change active, first validate the changes by using the command:

sudo netplan try

This should return a message informing you whether the new configuration is valid or not. If the configuration is not valid, then the system revert to the previous settings, and the likely cause of the error is a typing mistake.

Once validated, apply the changes using the following command:

sudo netplan apply

If you did not install a desktop environment, i.e., you are running "headless" Ubuntu, then you can set the fixed IP address by editing the 50-clound-init.yaml file to be the following:

network:
    version: 2
    ethernets:
        eth0:
            dhcp4: false
            addresses: [10.42.0.11/24]
            gateway4: 10.42.0.0
            nameservers:
                addresses: [8.8.8.8,8.8.4.4]

The address 10.42.0.11/24 should be replaced by the IP address and netmask you desire. The /24 specified the most comment netmask of 255.255.255.0. It is also possible to leave out the gateway4 and nameservers specifications if the defaults are appropriate.

Then try and aply the changes as described above.

The following are some useful commands for checking the current connection status:

ifconfig

nmcli c show