TS-4900 Ubuntu Sections
Ubuntu is a distribution provided by Canonical which is based on Debian. Ubuntu often has more recent packages but follows a shorter release cycle. The image we provide is based on Ubuntu. We use the root filesystem, but the kernel is not provided by Ubuntu or in any way associated with Canonical.
This image includes support for the TS-4900, TS-7970, and TS-TPC-7990.
Ubuntu 23.04 - Lunar
Ubuntu 23.04 - Getting Started
This Ubuntu release is available in 3 flavors with various packages.
| Image | Estimated Size | Description |
|---|---|---|
| ubuntu-armhf-23.04-x11-latest.tar.bz2 | 1068 MiB |
|
| ubuntu-armhf-23.04-headless-latest.tar.bz2 | 845 MiB |
|
| ubuntu-armhf-23.04-minimal-latest.tar.bz2 | 207 MiB |
|
The default login is "user/user" which includes sudo permissions.
To write this to an SD card, first partition the SD card to have one large ext3, or ext4 partition. See the guide here for more information. Once it is formatted, extract this tar with:
# Assuming your SD card is /dev/sdc with one partition
mkfs.ext3 /dev/sdc1
mkdir /mnt/sd/
sudo mount /dev/sdc1 /mnt/sd/
sudo tar --numeric-owner -xjf ubuntu-armhf-23.04-latest.tar.bz2 -C /mnt/sd
sudo umount /mnt/sd
sync
To rewrite the eMMC, boot to the SD card. You cannot rewrite the emmc while it is mounted elsewhere, or used to currently boot the system. Once booted to the SD, run:
mkfs.ext3 /dev/mmcblk2p1
mkdir /mnt/emmc
mount /dev/mmcblk2p1 /mnt/emmc
wget -qO- https://files.embeddedTS.com/ts-socket-macrocontrollers/ts-4900-linux/distributions/ubuntu/ubuntu-armhf-23.04-x11-latest.tar.bz2 | tar --numeric-owner -xj -C /mnt/emmc/
umount /mnt/emmc
sync
| Note: | The ext4 filesystem can be used instead of ext3, but it may require additional options. U-Boot does not support the 64bit addressing added as the default behavior in recent revisions of mkfs.ext4. If using e2fsprogs 1.43 or newer, the options "-O ^64bit,^metadata_csum" must be used with ext4 for proper compatibility. Older versions of e2fsprogs do not need these options passed nor are they needed for ext3. |
Ubuntu 23.04 - Networking
The network in Ubuntu is configured netplan. For complete documentation, see Netplan's documentation here
Some common examples are shown below. On this release network interfaces follow the predictible network interface names. Run ip addr show to get a list of the network interfaces.
Most commonly:
- end0 - Ethernet device 0 (CPU Ethernet)
- enp1s0 - Ethernet PCIe port 1 slot 0 ethernet
- usb<mac> - USB ethernet
- wlan0 - WIFI
DHCP on end0. Edit the file /etc/netplan/ethernet.yaml and add:
network:
version: 2
renderer: networkd
ethernets:
end0:
dhcp4: true
dhcp6: true
Static IP on end0. Edit the file /etc/netplan/ethernet.yaml and add:
network:
version: 2
renderer: networkd
ethernets:
end0:
dhcp4: no
addresses: [192.168.0.50/24]
gateway4: 192.168.0.1
nameservers:
addresses: [8.8.8.8,8.8.4.4]
After creating the yaml file, set the appropriate permissions and apply the netplan:
sudo chmod 600 /etc/netplan/*.yaml
sudo netplan apply
Ubuntu 23.04 - WIFI Client
Wireless configuration under Ubuntu, similar to Ethernet, also uses netplan for configuration. For example, create /etc/netplan/wifi.yaml:
network:
version: 2
renderer: networkd
wifis:
wlan0:
dhcp4: yes
dhcp6: yes
access-points:
"yourssid":
password: yourpassphrase"
After creating the yaml file, set the appropriate permissions and apply the netplan:
sudo chmod 600 /etc/netplan/*.yaml
sudo netplan apply
Ubuntu 23.04 - WIFI Access Point
First, hostapd needs to be installed in order to manage the access point on the device:
apt-get update && apt-get install hostapd -y
| Note: | The install process will start an unconfigured hostapd process. This process must be killed and restarted before a new hostapd.conf will take effect. |
Edit /etc/hostapd/hostapd.conf to include the following lines:
interface=wlan0 driver=nl80211 ssid=YourAPName channel=1
| Note: | Refer to the kernel's hostapd documentation for more wireless configuration options. |
To start the access point launch hostapd:
hostapd /etc/hostapd/hostapd.conf &
This will start up an access point that can be detected by WIFI clients. A DHCP server will likely be desired to assign IP addresses. Refer to Debian's documentation for more details on DHCP configuration.
Ubuntu 23.04 - Installing New Software
Ubuntu provides the apt-get system which lets you manage pre-built applications. Before you do this you need to update Ubuntu's list of package versions and locations. This assumes you have a valid network connection to the internet.
apt-get update
For example, lets say you wanted to install openjdk for Java support. You can use the apt-cache command to search the local cache of Debian's packages.
root@ts-imx6:~# apt-cache search openjdk jvm-7-avian-jre - lightweight virtual machine using the OpenJDK class library freemind - Java Program for creating and viewing Mindmaps icedtea-7-plugin - web browser plugin based on OpenJDK and IcedTea to execute Java applets default-jdk - Standard Java or Java compatible Development Kit default-jdk-doc - Standard Java or Java compatible Development Kit (documentation) default-jre - Standard Java or Java compatible Runtime default-jre-headless - Standard Java or Java compatible Runtime (headless) jtreg - Regression Test Harness for the OpenJDK platform libreoffice - office productivity suite (metapackage) icedtea-7-jre-jamvm - Alternative JVM for OpenJDK, using JamVM openjdk-7-dbg - Java runtime based on OpenJDK (debugging symbols) openjdk-7-demo - Java runtime based on OpenJDK (demos and examples) openjdk-7-doc - OpenJDK Development Kit (JDK) documentation openjdk-7-jdk - OpenJDK Development Kit (JDK) openjdk-7-jre - OpenJDK Java runtime, using Hotspot Zero openjdk-7-jre-headless - OpenJDK Java runtime, using Hotspot Zero (headless) openjdk-7-jre-lib - OpenJDK Java runtime (architecture independent libraries) openjdk-7-source - OpenJDK Development Kit (JDK) source files uwsgi-app-integration-plugins - plugins for integration of uWSGI and application uwsgi-plugin-jvm-openjdk-7 - Java plugin for uWSGI (OpenJDK 7) uwsgi-plugin-jwsgi-openjdk-7 - JWSGI plugin for uWSGI (OpenJDK 7)
In this case you will likely want openjdk-7-jre to provide a runtime environment, and possibly openjdk-7-jdk to provide a development environment.
Once you have the package name you can use apt-get to install the package and any dependencies. This assumes you have a network connection to the internet.
apt-get install openjdk-7-jre
# You can also chain packages to be installed
apt-get install openjdk-7-jre nano vim mplayer
For more information on using apt-get refer to Ubuntu's documentation here.
Ubuntu 23.04 - Setting up SSH
To install ssh, install the package as normal with apt-get:
apt-get install openssh-server
Make sure the device is configured on the network and set a password for the remote user. SSH will not allow remote connections without a password or a valid SSH key pair.
passwd root
| Note: | The default OpenSSH server will not permit root to login via SSH as a security precaution. To allow root to log in via ssh anyway, edit the /etc/ssh/sshd_config file and add the line PermitRootLogin yes in the authentication section. This change will take effect after reboot or after sshd service restart.
|
After this setup it is now possible to connect from a remote PC supporting SSH. On Linux/OS X this is the "ssh" command, or from Windows using a client such as PuTTY.
| Note: | If a DNS server is not present on the target network, it is possible to save time at login by adding "UseDNS no" in /etc/ssh/sshd_config. |
Ubuntu 23.04 - Starting Automatically
A systemd service can be created to start up headless applications. Create a file in /etc/systemd/system/yourapp.service
[Unit]
Description=Run an application on startup
[Service]
Type=simple
ExecStart=/usr/local/bin/your_app_or_script
[Install]
WantedBy=multi-user.target
If networking is a dependency add "After=network.target" in the Unit section. Once you have this file in place add it to startup with:
# Start the app on startup, but will not start it now
systemctl enable yourapp.service
# Start the app now, but doesn't change auto startup
systemctl start yourapp.service
| Note: | See the systemd documentation for in depth documentation on services. |
Ubuntu 20.04 - Focal
Ubuntu 20.04 - Getting Started
The latest release is available here:
The login is either "root" with no password, or username "ubuntu" with the password "ubuntu". The ubuntu user is allowed to run sudo.
To write this to an SD card, first partition the SD card to have one large ext3, or ext4 partition. See the guide here for more information. Once it is formatted, extract this tar with:
# Assuming your SD card is /dev/sdc with one partition
mkfs.ext3 /dev/sdc1
mkdir /mnt/sd/
sudo mount /dev/sdc1 /mnt/sd/
sudo tar --numeric-owner -xjf ubuntu-armhf-20.04-latest.tar.bz2 -C /mnt/sd
sudo umount /mnt/sd
sync
To rewrite the eMMC, boot to the SD card. You cannot rewrite the emmc while it is mounted elsewhere, or used to currently boot the system. Once booted to the SD, run:
mkfs.ext3 /dev/mmcblk2p1
mkdir /mnt/emmc
mount /dev/mmcblk2p1 /mnt/emmc
wget -qO- https://files.embeddedTS.com/ts-socket-macrocontrollers/ts-4900-linux/distributions/ubuntu/ubuntu-armhf-20.04-latest.tar.bz2 | tar --numeric-owner -xj -C /mnt/emmc/
umount /mnt/emmc
sync
| Note: | The ext4 filesystem can be used instead of ext3, but it may require additional options. U-Boot does not support the 64bit addressing added as the default behavior in recent revisions of mkfs.ext4. If using e2fsprogs 1.43 or newer, the options "-O ^64bit,^metadata_csum" must be used with ext4 for proper compatibility. Older versions of e2fsprogs do not need these options passed nor are they needed for ext3. |
Ubuntu 20.04 - Networking
The network in Ubuntu is configured netplan. For complete documentation, see Netplan's documentation here
Some common examples are shown below. On this release network interfaces follow the predictible network interface names. Run ip addr show to get a list of the network interfaces.
Most commonly:
- end0 - Ethernet device 0 (CPU Ethernet)
- enp1s0 - Ethernet PCIe port 1 slot 0 ethernet
- usb<mac> - USB ethernet
- wlan0 - WIFI
DHCP on end0. Edit the file /etc/netplan/ethernet.yaml and add:
network:
version: 2
renderer: networkd
ethernets:
end0:
dhcp4: true
dhcp6: true
Static IP on end0. Edit the file /etc/netplan/ethernet.yaml and add:
network:
version: 2
renderer: networkd
ethernets:
end0:
dhcp4: no
addresses: [192.168.0.50/24]
gateway4: 192.168.0.1
nameservers:
addresses: [8.8.8.8,8.8.4.4]
After creating the yaml file, set the appropriate permissions and apply the netplan:
sudo chmod 600 /etc/netplan/*.yaml
sudo netplan apply
Ubuntu 20.04 - WIFI Client
If connecting to a WPA/WPA2 network, a wpa_supplicant config file must first be created:
wpa_passphrase yournetwork yournetworkpassphrase > /etc/wpa_supplicant/wpa_supplicant-wlan0.conf
Create the file /lib/systemd/system/wpa_supplicant@.service with these contents
[Unit]
Description=WPA supplicant daemon (interface-specific version)
Requires=sys-subsystem-net-devices-%i.device
After=sys-subsystem-net-devices-%i.device
[Service]
Type=simple
ExecStart=/sbin/wpa_supplicant -c/etc/wpa_supplicant/wpa_supplicant-%I.conf -i%I
[Install]
Alias=multi-user.target.wants/wpa_supplicant@%i.service
Next, enable the service to start up on boot:
systemctl enable wpa_supplicant@wlan0
Create the file /etc/systemd/network/wlan0.network with:
[Match]
Name=wlan0
[Network]
DHCP=yes
Enable networkd to run dhcp on startup:
systemctl enable systemd-networkd
See the systemctl-networkd example for setting a static IP for a network interface. The wlan0.network can be configured the same way as an eth.network. To enable all of the changes that have been made, run the following commands:
systemctl enable wpa_supplicant@wlan0
systemctl start wpa_supplicant@wlan0
systemctl restart systemd-networkd
Ubuntu 20.04 - WIFI Access Point
First, hostapd needs to be installed in order to manage the access point on the device:
apt-get update && apt-get install hostapd -y
| Note: | The install process will start an unconfigured hostapd process. This process must be killed and restarted before a new hostapd.conf will take effect. |
Edit /etc/hostapd/hostapd.conf to include the following lines:
interface=wlan0 driver=nl80211 ssid=YourAPName channel=1
| Note: | Refer to the kernel's hostapd documentation for more wireless configuration options. |
To start the access point launch hostapd:
hostapd /etc/hostapd/hostapd.conf &
This will start up an access point that can be detected by WIFI clients. A DHCP server will likely be desired to assign IP addresses. Refer to Debian's documentation for more details on DHCP configuration.
Ubuntu 20.04 - Installing New Software
Ubuntu provides the apt-get system which lets you manage pre-built applications. Before you do this you need to update Ubuntu's list of package versions and locations. This assumes you have a valid network connection to the internet.
apt-get update
For example, lets say you wanted to install openjdk for Java support. You can use the apt-cache command to search the local cache of Debian's packages.
root@ts-imx6:~# apt-cache search openjdk jvm-7-avian-jre - lightweight virtual machine using the OpenJDK class library freemind - Java Program for creating and viewing Mindmaps icedtea-7-plugin - web browser plugin based on OpenJDK and IcedTea to execute Java applets default-jdk - Standard Java or Java compatible Development Kit default-jdk-doc - Standard Java or Java compatible Development Kit (documentation) default-jre - Standard Java or Java compatible Runtime default-jre-headless - Standard Java or Java compatible Runtime (headless) jtreg - Regression Test Harness for the OpenJDK platform libreoffice - office productivity suite (metapackage) icedtea-7-jre-jamvm - Alternative JVM for OpenJDK, using JamVM openjdk-7-dbg - Java runtime based on OpenJDK (debugging symbols) openjdk-7-demo - Java runtime based on OpenJDK (demos and examples) openjdk-7-doc - OpenJDK Development Kit (JDK) documentation openjdk-7-jdk - OpenJDK Development Kit (JDK) openjdk-7-jre - OpenJDK Java runtime, using Hotspot Zero openjdk-7-jre-headless - OpenJDK Java runtime, using Hotspot Zero (headless) openjdk-7-jre-lib - OpenJDK Java runtime (architecture independent libraries) openjdk-7-source - OpenJDK Development Kit (JDK) source files uwsgi-app-integration-plugins - plugins for integration of uWSGI and application uwsgi-plugin-jvm-openjdk-7 - Java plugin for uWSGI (OpenJDK 7) uwsgi-plugin-jwsgi-openjdk-7 - JWSGI plugin for uWSGI (OpenJDK 7)
In this case you will likely want openjdk-7-jre to provide a runtime environment, and possibly openjdk-7-jdk to provide a development environment.
Once you have the package name you can use apt-get to install the package and any dependencies. This assumes you have a network connection to the internet.
apt-get install openjdk-7-jre
# You can also chain packages to be installed
apt-get install openjdk-7-jre nano vim mplayer
For more information on using apt-get refer to Ubuntu's documentation here.
Ubuntu 20.04 - Setting up SSH
To install ssh, install the package as normal with apt-get:
apt-get install openssh-server
Make sure the device is configured on the network and set a password for the remote user. SSH will not allow remote connections without a password or a valid SSH key pair.
passwd root
| Note: | The default OpenSSH server will not permit root to login via SSH as a security precaution. To allow root to log in via ssh anyway, edit the /etc/ssh/sshd_config file and add the line PermitRootLogin yes in the authentication section. This change will take effect after reboot or after sshd service restart.
|
After this setup it is now possible to connect from a remote PC supporting SSH. On Linux/OS X this is the "ssh" command, or from Windows using a client such as PuTTY.
| Note: | If a DNS server is not present on the target network, it is possible to save time at login by adding "UseDNS no" in /etc/ssh/sshd_config. |
Ubuntu 20.04 - Starting Automatically
A systemd service can be created to start up headless applications. Create a file in /etc/systemd/system/yourapp.service
[Unit]
Description=Run an application on startup
[Service]
Type=simple
ExecStart=/usr/local/bin/your_app_or_script
[Install]
WantedBy=multi-user.target
If networking is a dependency add "After=network.target" in the Unit section. Once you have this file in place add it to startup with:
# Start the app on startup, but will not start it now
systemctl enable yourapp.service
# Start the app now, but doesn't change auto startup
systemctl start yourapp.service
| Note: | See the systemd documentation for in depth documentation on services. |
Ubuntu 18.04 - Xenial
Ubuntu 18.04 - Getting Started
The latest release is available here:
The login is either "root" with no password, or username "ubuntu" with the password "ubuntu". The ubuntu user is allowed to run sudo.
To write this to an SD card, first partition the SD card to have one large ext3, or ext4 partition. See the guide here for more information. Once it is formatted, extract this tar with:
# Assuming your SD card is /dev/sdc with one partition
mkfs.ext3 /dev/sdc1
mkdir /mnt/sd/
sudo mount /dev/sdc1 /mnt/sd/
sudo tar --numeric-owner -xjf ubuntu-armhf-18.04-latest.tar.bz2 -C /mnt/sd
sudo umount /mnt/sd
sync
To rewrite the eMMC, boot to the SD card. You cannot rewrite the emmc while it is mounted elsewhere, or used to currently boot the system. Once booted to the SD, run:
mkfs.ext3 /dev/mmcblk2p1
mkdir /mnt/emmc
mount /dev/mmcblk2p1 /mnt/emmc
wget -qO- https://files.embeddedTS.com/ts-socket-macrocontrollers/ts-4900-linux/distributions/ubuntu/ubuntu-armhf-18.04-latest.tar.bz2 | tar --numeric-owner -xj -C /mnt/emmc/
umount /mnt/emmc
sync
| Note: | The ext4 filesystem can be used instead of ext3, but it may require additional options. U-Boot does not support the 64bit addressing added as the default behavior in recent revisions of mkfs.ext4. If using e2fsprogs 1.43 or newer, the options "-O ^64bit,^metadata_csum" must be used with ext4 for proper compatibility. Older versions of e2fsprogs do not need these options passed nor are they needed for ext3. |
Ubuntu 18.04 - Networking
From almost any Linux system you can use "ip" or the ifconfig/route commands to set up the network.
# Bring up the CPU network interface
ifconfig eth0 up
# Or if you're on a baseboard with a second ethernet port, you can use that as:
ifconfig eth1 up
# Set an ip address (assumes 255.255.255.0 subnet mask)
ifconfig eth0 192.168.0.50
# Set a specific subnet
ifconfig eth0 192.168.0.50 netmask 255.255.0.0
# Configure your route. This is the server that provides your internet connection.
route add default gw 192.168.0.1
# Edit /etc/resolv.conf for your DNS server
echo "nameserver 192.168.0.1" > /etc/resolv.conf
Most networks will offer DHCP which can be set up with one command:
# To setup the default CPU ethernet port
dhclient eth0
# Or if you're on a baseboard with a second ethernet port, you can use that as:
dhclient eth1
# You can configure all ethernet ports for a dhcp response with
dhclient
To make DHCP run on startup systemd's networking will need to be configured.
In /etc/systemd/network/eth.network
[Match]
Name=eth*
[Network]
DHCP=yes
Then, if you intend to use DHCP to configure your DNS, start and enable the network name resolver service:
systemctl start systemd-resolved.service
systemctl enable systemd-resolved.service
ln -s /run/systemd/resolve/resolv.conf /etc/resolv.conf
For a static configuration create a config file for that specific interface. /etc/systemd/network/eth0.network
[Match]
Name=eth0
[Network]
Address=192.168.0.50/24
Gateway=192.168.0.1
DNS=192.168.0.1
For more information on networking, see Ubuntu and systemd's documentation:
Ubuntu 18.04 - WIFI Client
If connecting to a WPA/WPA2 network, a wpa_supplicant config file must first be created:
wpa_passphrase yournetwork yournetworkpassphrase > /etc/wpa_supplicant/wpa_supplicant-wlan0.conf
Create the file /lib/systemd/system/wpa_supplicant@.service with these contents
[Unit]
Description=WPA supplicant daemon (interface-specific version)
Requires=sys-subsystem-net-devices-%i.device
After=sys-subsystem-net-devices-%i.device
[Service]
Type=simple
ExecStart=/sbin/wpa_supplicant -c/etc/wpa_supplicant/wpa_supplicant-%I.conf -i%I
[Install]
Alias=multi-user.target.wants/wpa_supplicant@%i.service
Next, enable the service to start up on boot:
systemctl enable wpa_supplicant@wlan0
Create the file /etc/systemd/network/wlan0.network with:
[Match]
Name=wlan0
[Network]
DHCP=yes
Enable networkd to run dhcp on startup:
systemctl enable systemd-networkd
See the systemctl-networkd example for setting a static IP for a network interface. The wlan0.network can be configured the same way as an eth.network. To enable all of the changes that have been made, run the following commands:
systemctl enable wpa_supplicant@wlan0
systemctl start wpa_supplicant@wlan0
systemctl restart systemd-networkd
Ubuntu 18.04 - WIFI Access Point
First, hostapd needs to be installed in order to manage the access point on the device:
apt-get update && apt-get install hostapd -y
| Note: | The install process will start an unconfigured hostapd process. This process must be killed and restarted before a new hostapd.conf will take effect. |
Edit /etc/hostapd/hostapd.conf to include the following lines:
interface=wlan0 driver=nl80211 ssid=YourAPName channel=1
| Note: | Refer to the kernel's hostapd documentation for more wireless configuration options. |
To start the access point launch hostapd:
hostapd /etc/hostapd/hostapd.conf &
This will start up an access point that can be detected by WIFI clients. A DHCP server will likely be desired to assign IP addresses. Refer to Debian's documentation for more details on DHCP configuration.
Ubuntu 18.04 - Installing New Software
Ubuntu provides the apt-get system which lets you manage pre-built applications. Before you do this you need to update Ubuntu's list of package versions and locations. This assumes you have a valid network connection to the internet.
apt-get update
For example, lets say you wanted to install openjdk for Java support. You can use the apt-cache command to search the local cache of Debian's packages.
root@ts-imx6:~# apt-cache search openjdk jvm-7-avian-jre - lightweight virtual machine using the OpenJDK class library freemind - Java Program for creating and viewing Mindmaps icedtea-7-plugin - web browser plugin based on OpenJDK and IcedTea to execute Java applets default-jdk - Standard Java or Java compatible Development Kit default-jdk-doc - Standard Java or Java compatible Development Kit (documentation) default-jre - Standard Java or Java compatible Runtime default-jre-headless - Standard Java or Java compatible Runtime (headless) jtreg - Regression Test Harness for the OpenJDK platform libreoffice - office productivity suite (metapackage) icedtea-7-jre-jamvm - Alternative JVM for OpenJDK, using JamVM openjdk-7-dbg - Java runtime based on OpenJDK (debugging symbols) openjdk-7-demo - Java runtime based on OpenJDK (demos and examples) openjdk-7-doc - OpenJDK Development Kit (JDK) documentation openjdk-7-jdk - OpenJDK Development Kit (JDK) openjdk-7-jre - OpenJDK Java runtime, using Hotspot Zero openjdk-7-jre-headless - OpenJDK Java runtime, using Hotspot Zero (headless) openjdk-7-jre-lib - OpenJDK Java runtime (architecture independent libraries) openjdk-7-source - OpenJDK Development Kit (JDK) source files uwsgi-app-integration-plugins - plugins for integration of uWSGI and application uwsgi-plugin-jvm-openjdk-7 - Java plugin for uWSGI (OpenJDK 7) uwsgi-plugin-jwsgi-openjdk-7 - JWSGI plugin for uWSGI (OpenJDK 7)
In this case you will likely want openjdk-7-jre to provide a runtime environment, and possibly openjdk-7-jdk to provide a development environment.
Once you have the package name you can use apt-get to install the package and any dependencies. This assumes you have a network connection to the internet.
apt-get install openjdk-7-jre
# You can also chain packages to be installed
apt-get install openjdk-7-jre nano vim mplayer
For more information on using apt-get refer to Ubuntu's documentation here.
Ubuntu 18.04 - Setting up SSH
To install ssh, install the package as normal with apt-get:
apt-get install openssh-server
Make sure the device is configured on the network and set a password for the remote user. SSH will not allow remote connections without a password or a valid SSH key pair.
passwd root
| Note: | The default OpenSSH server will not permit root to login via SSH as a security precaution. To allow root to log in via ssh anyway, edit the /etc/ssh/sshd_config file and add the line PermitRootLogin yes in the authentication section. This change will take effect after reboot or after sshd service restart.
|
After this setup it is now possible to connect from a remote PC supporting SSH. On Linux/OS X this is the "ssh" command, or from Windows using a client such as PuTTY.
| Note: | If a DNS server is not present on the target network, it is possible to save time at login by adding "UseDNS no" in /etc/ssh/sshd_config. |
Ubuntu 18.04 - Starting Automatically
A systemd service can be created to start up headless applications. Create a file in /etc/systemd/system/yourapp.service
[Unit]
Description=Run an application on startup
[Service]
Type=simple
ExecStart=/usr/local/bin/your_app_or_script
[Install]
WantedBy=multi-user.target
If networking is a dependency add "After=network.target" in the Unit section. Once you have this file in place add it to startup with:
# Start the app on startup, but will not start it now
systemctl enable yourapp.service
# Start the app now, but doesn't change auto startup
systemctl start yourapp.service
| Note: | See the systemd documentation for in depth documentation on services. |
To start an application on bootup with X11 instead change the x-session-manager. By default the system starts xfce:
root@ts:~# ls -lah /usr/bin/x-session-manager
lrwxrwxrwx 1 root root 35 May 26 2015 /usr/bin/x-session-manager -> /etc/alternatives/x-session-manager
root@ts:~# ls -lah /etc/alternatives/x-session-manager
lrwxrwxrwx 1 root root 19 May 26 2015 /etc/alternatives/x-session-manager -> /usr/bin/startxfce4
The x-session can be modified to only start specified processes. Create the file /usr/bin/mini-x-session with these contents:
#!/bin/bash
matchbox-window-manager -use_titlebar no &
exec xfce4-terminal
You may need to "apt-get install matchbox-window-manager." first. This is a tiny window manager which also has a few flags that simplify embedded use. Now enable this session manager and restart slim to restart x11 and show it now.
chmod a+x /usr/bin/mini-x-session
rm /etc/alternatives/x-session-manager
ln -s /usr/bin/mini-x-session /etc/alternatives/x-session-manager
service slim restart
If the x-session-manager process ever closes x11 will restart. The exec command allows a new process to take over the existing PID. In the above example xfce4-terminal takes over the PID of x-session-manager. If the terminal is closed with commands like exit the slim/x11 processes will restart.